Adaptogens · Herbs & Botanicals · Sacred Indian basil with low-certainty evidence

Holy Basil (Tulsi)

Q: Does holy basil help with stress?

It may help a little, but the confidence is low. Two placebo-controlled trials of branded extracts (OciBest in 150 adults for 6 weeks, Holixer in 100 adults for 8 weeks) found lower stress scores than placebo, and the newer one also found lower hair cortisol. Both were funded by or linked to the extract makers, and no independent group has repeated them. Sleep looked a little better in the same trials (low certainty).

Q: Does holy basil help with anxiety?

There is no good evidence yet. The only anxiety study in patients was small (35 people with generalized anxiety disorder), ran for 60 days and had no placebo group, so it cannot show the herb caused the improvement. The stress trials give only indirect hints. Certainty is very low. Anxiety that is affecting daily life deserves a proper check-up.

Q: Does holy basil lower blood sugar?

It is the one effect with a real human signal, but the certainty is low. In a 1996 single-blind crossover trial in people with type 2 diabetes, holy basil leaves lowered fasting blood glucose by about 21 mg/dl compared with placebo. A review of 24 human studies (most from India, many old) found good results, but only 8 of the 24 had a placebo group and only 7 were high quality. It is not a replacement for diabetes medicine.

Q: Does holy basil lower cholesterol?

Maybe a little, but the evidence is low certainty. A handful of small trials report better triglycerides, LDL and HDL. In the one trial we could read (30 overweight young adults, 8 weeks), all three improved compared with the start, but only HDL was clearly better than the untreated group.

Q: Does holy basil affect fertility or pregnancy?

Nobody knows for people. No human study has looked at fertility, sperm or pregnancy outcomes with holy basil. In rats and rabbits, extracts changed hormones, lowered sperm counts (which recovered after stopping in one rat study) and reduced ovulation. Animal results do not prove harm in people, but they are the reason to avoid concentrated products while trying to conceive.

Q: Does holy basil affect the thyroid?

No human thyroid data were found. In male mice, a leaf extract lowered the thyroid hormone T4 (0.5 g/kg for 15 days). If you have a thyroid condition or take thyroid medicine, ask your prescriber before using concentrated holy basil.

Q: Can I take holy basil with diabetes medicine?

Only with your prescriber's knowledge. Holy basil lowered blood sugar in trials, so with insulin or glucose-lowering tablets the effects could add up and cause low blood sugar. The sources we read did not report low-sugar episodes, but they were not designed to look for them. Check your sugars more often when you start, and know the signs: sweating, shakiness, hunger and confusion.

Q: Is holy basil safe in pregnancy or while breastfeeding?

Not enough is known, so avoid concentrated products. There is no human pregnancy or breast-milk safety information. Rat studies found hormone and fertility effects, which is a precaution and not proof of harm. Tea in food-like amounts is a different thing from capsules and extracts, but no source separates the two. Ask your doctor.

Q: What about tulsi tea?

Tea is how tulsi is traditionally taken, but the stress trials used branded extracts and no trial of tea or plain leaf powder for stress, mood or thinking was found. So the trial results cannot be assumed for tea. The one tea study found was in people having radioactive iodine treatment, and it looked at anxiety and mouth side effects. For amounts, ask a doctor or pharmacist. Check that a label names Ocimum tenuiflorum (also called Ocimum sanctum).

Q: What is the difference between holy basil and sweet basil?

They are different plants in the same genus. Holy basil or tulsi is Ocimum tenuiflorum. Sweet basil (Ocimum basilicum) is the pesto and Italian-cooking basil. The research on holy basil should not be applied to sweet basil. Mix-ups happen in the market: a 2024 survey of 30 'tulsi' powders in India found 2 were actually another basil species (Ocimum gratissimum), and a review says European tulsi products have shown substitution with other herbs, including sweet basil (that review was not checked at its original source).

Ocimum tenuiflorum L. (also Ocimum sanctum L.) · also called Holy basil, sacred basil, tulsi, tulasi, Krishna tulsi (purple type), albahaca sagrada and albahaca morada (Spanish), basilic sacré (French)

Holy basil, or tulsi, is a fragrant mint-family plant that is sacred in India and long used in Ayurveda as a tea and herbal remedy. The leaf is taken as a tea, capsule or extract, mainly for stress. Confidence is low: the two main stress trials were positive but both were linked to the extract makers and have not been repeated independently. The one real human signal is a drop in fasting blood sugar, also low certainty. Claims about fertility, thyroid, bleeding and drug interactions come only from animals or test tubes. It is not sweet basil, and products are sometimes the wrong species.

General information, not medical advice. Last substantive update October 25, 2026 · Not medically reviewed. A named clinician has not signed off on this page. How this page is made

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About Holy Basil (Tulsi)

Holy basil (tulsi, Ocimum tenuiflorum) is a sacred Indian herb whose leaf is taken as a tea, capsule or extract, mainly for stress. The evidence is weak. For stress and sleep it is low certainty, resting on two placebo-controlled trials of branded extracts that were both linked to the extract makers and never repeated independently. For anxiety, mood, thinking and fatigue it is very low. The one real human signal is a fall in fasting blood sugar (about 21 mg/dl in one crossover trial), low certainty: a 24-study review had only 8 placebo-controlled studies and 7 of high quality. Everything on fertility, thyroid, bleeding and clotting, and drug interactions is from animals or test tubes, and no human data were found. In human trials, which lasted up to 13 weeks, holy basil was well tolerated. People taking diabetes medicine should watch for low blood sugar. A 2024 survey found 2 of 30 'tulsi' powders were another basil species. Ask a doctor or pharmacist about amounts.

What it is

Holy basil, also called tulsi, is Ocimum tenuiflorum (older papers call it Ocimum sanctum), a fragrant plant in the mint family (Lamiaceae). It is native to India and nearby countries and is widely grown in pots, gardens and temple courtyards. The leaf smells of cloves, which is mostly from a compound called eugenol.

It is not sweet basil (Ocimum basilicum), the pesto basil, and research on one should not be applied to the other. 'Tulsi' on a label is not always the right plant: a 2024 DNA survey of 30 market powders found 2 were Ocimum gratissimum, and the name 'vana tulsi' often points to that other species.

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What makes it distinctive

Tulsi leaf holds a mix of oil compounds (eugenol, caryophyllene), plant acids (ursolic and oleanolic acid), flavones and rosmarinic acid. Green (Rama) and purple (Krishna) types differ in make-up, and purple types may carry more methyl eugenol, a compound one author group describes as potentially harmful.

In cell and animal work, tulsi extract calmed the body's stress-hormone system. This has not been shown to be how it works in people, and no one knows which compound does the work, since all the human trials used the whole leaf or leaf extracts.

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Historical and current uses

In Ayurveda and Hindu household practice tulsi is the 'Queen of Herbs' and is worshipped as a goddess. It is taken daily as a tea and used for cough, asthma, fever, indigestion, skin problems and stress. These are traditional uses, not proof. Classical texts are often said to describe it, but the verses and dates were not checked at a source.

Today it is sold as a stress and general wellbeing herb, as tea, capsules and extracts, and in some mouthwashes and toothpastes. Modern reviews call it an adaptogen; one author is a paid consultant to a tulsi company, so the tone of that review is promotional.

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What the research shows

For stress, two placebo-controlled trials of branded extracts found lower stress scores, and the newer one found lower hair cortisol. Both were linked to the extract makers and neither has been repeated by others. Sleep improved a little in the same trials. For anxiety, mood, thinking and fatigue there is almost nothing: one small uncontrolled anxiety study and one small attention study.

For blood sugar, several small Indian trials found lower fasting and after-meal sugar in type 2 diabetes. In the 24-study review only 8 had a placebo group and 7 were high quality, so this is promising but low certainty. Cholesterol, immune markers and gum health show small low-certainty signals. For fertility, thyroid, skin, cough and asthma there are no human trials.

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At a glance

Traditional uses history, not proof

Sacred plant in Hindu households, kept in pots and courtyards in India
Ayurvedic 'Queen of Herbs', taken daily as a tea or leaf preparation and called an adaptogen, a herb said to help the body cope with stress
Traditional remedy for cough, asthma, fever, indigestion, skin problems and insect bites
Classical Ayurvedic texts are often said to describe it, but those verses were not verified here

Studied for research

Stress and sleep, low certainty
Anxiety, mood, thinking and fatigue, very low certainty
Fasting blood sugar in type 2 diabetes, low certainty
Cholesterol, immune markers and gum health, low certainty
Fertility, thyroid, bleeding and drug interactions: animal or test-tube findings only, no human data found

Main compounds

Eugenol, the clove-smelling oil in the leaf
Ursolic and oleanolic acid (plant triterpenes)
Flavones (apigenin, luteolin) and rosmarinic acid

Common forms

Leaf tea (the traditional form)
Branded leaf extracts such as OciBest and Holixer (used in the stress trials)
Leaf powder, capsules and tinctures
Mouthwash, toothpaste and gum gels (dental trials)
Products called 'vana tulsi' or sold as tulsi may be another basil species

Research links: PubMed: systematic review of 24 human studies of tulsi (2017) · PubMed: 8-week placebo-controlled stress trial (2022) · PubMed: DNA test of 30 tulsi powders (2024) · Research Library · Genes & Biomarkers Library

The plant and its history

Accepted scientific name: Ocimum tenuiflorum L.
Naming authority: L. (Linnaeus, Sp. Pl. 597, 1753), accepted species in GBIF (usageKey 2927100) and NCBI Taxonomy (taxid 204149)
Synonyms: Ocimum sanctum L. (the name used in most older papers; GBIF treats it as a synonym of O. tenuiflorum, usageKey 2927101; NCBI lists 'Ocimum sanctum' as a synonym); GBIF lists 19 synonyms in all, e.g. Ocimum monachorum L., Ocimum frutescens Burm.f., Ocimum hirsutum Benth., Ocimum inodorum Burm.f., Ocimum villosum Roxb., Ocimum tomentosum Lam., Geniosporum tenuiflorum (L.) Merr., Moschosma tenuiflorum (L.) Heynh., Plectranthus monachorum (L.) Spreng.
Common names: Holy basil; sacred basil; tulsi; tulasi; Krishna tulsi (purple type); brush-leaf-tea (English); Albahaca morada; albahaca sagrada; tulsi (Spanish); Basilic sacre (French); Tulsi / tulasi (Hindi, Marathi, Nepali, Urdu spellings differ); Kemangi hutan and Ruku-ruku (Indonesian); Kaphrao / krapao (Thai, the stir-fry basil) (South and Southeast Asia)
Botanical family: Lamiaceae (the mint family, tribe Ocimeae), which also holds sweet basil, mint, rosemary, sage, thyme and lavender (NCBI Taxonomy lineage).
Classification: Plantae > Tracheophyta > Magnoliopsida > Lamiales > Lamiaceae > Ocimum > Ocimum tenuiflorum
Native range: GBIF lists the plant as present across India (almost throughout), Nepal, Pakistan, Bangladesh, Sri Lanka, Myanmar, Thailand, Laos, Cambodia, Vietnam, Malaysia, southern China and parts of Arabia, with other places marked as introduced (GBIF distribution records, s-gbif-ocimum-tenuiflorum). A 2014 review says it is thought to have originated in north-central India (p25624701). Kew POWO was not checked.
Habitat: Warm tropical and subtropical regions; widely grown in home gardens, pots and temple courtyards in India (p25624701). Detailed wild habitat not verified in a primary source.
What the plant looks like: Roots: Roots are used in some folk practices (p22228948 lists roots among parts used), but the leaf is the part studied in the human trials and sold as tulsi.; Stems: Not described in a source read for this file.; Leaves: Aromatic leaves with a clove-like smell, attributed to eugenol (p25624701). Green (Rama / 'Sri') and purple-green (Krishna) leaf types exist (p17225591, p38520476).; Flowers: Not described in a source read for this file.; Fruit: Not described in a source read for this file.
Cultivation: Grown as a pot and garden plant in India; has also been grown in controlled plant factories in Thailand for research (p36340360). Further cultivation detail not verified.
Harvest and processing: Leaves are used fresh, dried as tea, or made into alcohol/water extracts. Essential oil is made by steam or hydrodistillation of the leaves (p39073007). Not verified beyond these papers.
Look-alikes and adulterants: Name: Sweet basil (Ocimum basilicum L.); Note: The common culinary basil in pesto and Italian cooking. GBIF (usageKey 2927096) and NCBI (taxid 39350) list it as a separate species in the same genus. It is not holy basil and the research on tulsi should not be applied to it. A rat study found both species' seed oils had anti-inflammatory effects, so they share some traits, but they are different plants (p10356964).; Name: Vana tulsi, wild tulsi (often Ocimum gratissimum L., clove basil / African basil); Note: 'Vana' means wild. In the trade the name usually points to Ocimum gratissimum, a different species (a 2023 Hungarian study grew 'African and Vana holy basil' as O. gratissimum, p38202372). In a 2024 market survey of 30 tulsi powders, two samples were not O. tenuiflorum and turned out to be O. gratissimum (p38520476). A 2014 review describes 'white Vana (wild) tulsi' as a lower-antioxidant type than Krishna tulsi (p25624701), without naming the species there. The botanical identity of 'Vana tulsi' is therefore not settled in the sources read and may differ by seller.; Name: Rama tulsi (green leaf) versus Krishna tulsi (purple leaf); Note: Both are Ocimum tenuiflorum. The Rama / 'Sri' type is green-leaved and the Krishna type is purple-black (p17225591: 'black (Krishna Tulasi) and green (Sri Tulasi) varieties'; p38520476: 'Green Tulsi and purple Tulsi are two subtypes in O. tenuiflorum and both have the same medicinal properties'). The Rama/Krishna wording is the common trade naming; the two papers use 'green/black/purple'. Lab content differs a little between them (see compounds).; Name: Other basils: lemon basil (O. x citriodorum), Thai sweet basil (O. basilicum var.), African blue basil; Note: Grown and sold as kitchen basils. A 2023 study profiled several of them next to green holy basil and found different main oil compounds (estragole, thymol, methyl cinnamate, linalool, eugenol) and holy basil oil content below 0.5% (p38202372).; Name: Thai holy basil (kaphrao); Note: The Thai stir-fry herb is Ocimum tenuiflorum (research on Thai holy basil cultivars is on that species, p36340360). The leaves taste peppery and are used as food; the same species is called tulsi in India.
Sustainability and conservation: No conservation concern found in the sources read; widely cultivated. IUCN status not checked.

Traditional use and history history, not clinical proof

Tradition or era	Documented use	Source
Ayurveda and Hindu household practice (India)	Tulsi is called 'The Incomparable One', 'Mother Medicine of Nature' and 'Queen of Herbs' in Ayurveda and is treated as sacred; in Hinduism the plant is worshipped as a goddess and many homes keep a tulsi plant in a pot or courtyard. Ayurveda describes the taste as hot and bitter and credits daily use with health, longevity and coping with stress. Traditional uses listed include cough, asthma, fever, diarrhoea, arthritis, eye and skin problems, indigestion and insect or snake bites.	p25624701
Ancient Ayurvedic texts (Charaka Samhita, Sushruta Samhita and others)	Often said to be described in the classical Ayurvedic texts and to be thousands of years old. I could not confirm the exact verses, dates or text names from a source read, so this is NOT verified here. The 2014 review states the tradition without citing a specific classical verse in the parts read.	NOT verified (p25624701 gives the tradition in general terms only)
Dose in classical practice	A 2014 review of Ayurvedic and pharmaceutical dosing looked at documented traditional dose ranges for tulsi leaves and at marketed products; its stated purpose was to question a European regulatory restriction that rested on a high-dose rabbit study. Dose figures are not given on this page; ask a doctor or pharmacist about amounts.	p25035537
Modern reviews: the 'adaptogen' label	A 2014 review calls tulsi a 'potent adaptogen' in the Ayurvedic sense of helping the body adapt to stress, and lists many animal and lab findings. The author discloses being a paid consultant to a tulsi-product company, so treat the tone as promotional and not as proof.	p25624701
Human research record (to 2017)	A systematic review found 24 human studies on tulsi (metabolic, heart, immunity and brain/stress outcomes). All reported favourable results and none reported significant side effects, but the reviewers say many studies were small and that dose and form need to be clarified. Quality is mixed; a list of only-positive results can also reflect publication bias.	p28400848
Important note	The items above describe tradition and use, not proof. Clinical benefit is judged only by trials (see the benefits and biomarkers files). Safety is in the safety file.	n/a

Traditional use shows how a plant was used. It does not show that a supplement works or is safe today.

What is inside, and how it may work

What the plant contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.

Main compounds

Compound	Family	Where it is concentrated	Activity studied	Level of evidence
Eugenol PubChem 3314	phenylpropene (the clove-smelling oil component)	Leaf (and the essential oil) Eugenol was 0.175 to 0.362% (w/w) of dried leaf in the samples of green and black tulsi measured by HPTLC (p17225591). In essential oil from four places in Vietnam it ranged from 9.0 to 44.0% (p39073007). Content varies a lot with variety and growth stage (p24420851, p36340360).	Main smell compound. In a test tube it blocked the COX-1 and COX-2 enzymes (97% COX-1 block at 1000 micromolar) and acted as an antioxidant at 10 micromolar (p10782484). In human liver-cell preparations it reduced the activity of drug-processing enzymes CYP2C9, CYP2D6 and CYP3A4 (p38841106). Rat work shows a long half-life after a single dose (p17321520). ^{8 31 42 7 33 71}	Laboratory research
Ursolic acid PubChem 64945	pentacyclic triterpene acid	Leaf 0.478% and 0.348% (w/w) in green tulsi from two sources, and 0.252% and 0.264% in black tulsi, by HPTLC (p17225591). That method could not separate ursolic from oleanolic acid on the plate; the paper used a stain to tell them apart.	In cell and test-tube assays, an O. sanctum extract and ursolic acid lowered cortisol release, blocked the CRH receptor CRHR1 and blocked the enzymes 11-beta-HSD1 and COMT (p26899341). That is lab data; the same group's rat trial used the whole extract, not ursolic acid alone. ^{8 38}	Laboratory research
Oleanolic acid PubChem 10494	pentacyclic triterpene acid (isomer of ursolic acid)	Leaf 0.174% and 0.218% (w/w) in black tulsi from two sources; not detected in the green type (p17225591).	Named as a main triterpene of O. tenuiflorum in a 2024 review (p39473808). No activity data for tulsi-specific oleanolic acid were read for this file. ^{8 15}	Laboratory research
Rosmarinic acid PubChem 5281792	phenolic acid (caffeic acid ester)	Leaf Isolated from fresh leaves and stems (p10782484). No general percentage of dried leaf was verified.	Antioxidant at 10 micromolar and a weak-to-moderate COX-1/COX-2 blocker in test tubes (58% COX-1 at 1000 micromolar) (p10782484). Human absorption data come from a perilla extract, not from tulsi (see pharmacokinetics). ^{42 15 9}	Laboratory research
Apigenin and its glycosides (apigenin-7-O-glucuronide, apigenin-7-O-glucoside) PubChem 5280443	flavone	Leaf Not verified. Isolated from leaf extract in two papers (p10782484, p17850106) without a content percentage in the abstracts read.	Free apigenin blocked COX-1 (65% at 1000 micromolar) and COX-2 in test tubes (p10782484). In rats, the apigenin glucuronide compound did not lower stress-raised corticosterone (p17850106). ^{42 34}	Laboratory research
Luteolin and its glycosides PubChem 5280445	flavone	Leaf Luteolin was 0.019 to 0.046% (w/w) of dried leaf in the samples tested (p17225591).	Luteolin glucosides were isolated from leaf extract (p17850106). No tulsi-specific activity result was read for luteolin itself. ^{8 34 15}	Laboratory research
Carvacrol PubChem 10364	monoterpene phenol	Essential oil (reported mainly for the related species O. gratissimum) Not verified for O. tenuiflorum. A review of O. gratissimum lists carvacrol among its oil compounds (p34901489). Carvacrol was not among the main oil compounds in the four O. tenuiflorum oils analysed in Vietnam (p39073007).	No tulsi-based activity result read. Listed because it is often quoted for 'basil' in general; do not credit tulsi with it without a tulsi-specific measurement. ^{89 31}	Laboratory research
Beta-caryophyllene ((E)-caryophyllene) PubChem 5281515	sesquiterpene (peppery, woody smell)	Essential oil 27.8 to 49.0% of the essential oil in four Vietnamese O. tenuiflorum samples, alongside trans-beta-elemene (20.3 to 37.1%) and eugenol (9.0 to 44.0%) (p39073007). Oil makes up under 0.5% of the plant in the green holy basil tested in Hungary (p38202372).	Outside tulsi, it bound the CB2 cannabinoid receptor (Ki 155 nM), was a CB2 agonist and cut inflammation in mice that have the receptor (not in mice lacking it) (p18574142). Whether the small amount in tulsi tea or capsules reaches such levels in people is not known. ^{31 57 30}	Animal research
Methyleugenol PubChem 7127	phenylpropene (methyl ether of eugenol)	Leaf and essential oil; higher in some chemotypes, reported higher in purple tulsi Seven O. tenuiflorum chemotypes rich in eugenol and methyleugenol were found, with methyleugenol changing during growth (p24420851). Purple tulsi was reported to contain more methyl eugenol, and 80% of 30 market powders tested were purple tulsi (p38520476). Thai accessions OC072 and OC081 were highest in methyl eugenol (p36340360).	Included because purple tulsi supply is dominated by a high methyl-eugenol type that the 2024 authors call 'moderately toxic and potentially carcinogenic' (p38520476). That safety statement is the authors' claim read in an abstract; safety detail belongs in the safety file. ^{71 10 20}	Laboratory research
Ocimumosides A and B (and ocimarin)	glycosides specific to O. sanctum (as named in the paper)	Leaf Not verified.	In rats, ocimumosides A and B (40 mg/kg by mouth) lowered stress-raised corticosterone and sugar and shifted brain chemical levels back toward normal; ocimarin did not (p17850106, p22455995). Animal data only; no human work. PubChem name search found no record for 'ocimumoside', so no CID is given. ^{34 4}	Animal research

Mechanisms, receptors and pathways

Target or pathway	Gene or receptor	What was found	Level
Stress hormone (cortisol) and the HPA stress axis	CRHR1; HSD11B1 (11-beta-HSD1); COMT	Lab: an O. sanctum extract and ursolic acid lowered cortisol release in cells, blocked the CRHR1 stress-signal receptor and inhibited 11-beta-HSD1 (which makes active cortisol) and COMT in test tubes. Animal: the extract improved body weight and cut immobility time in rats under 16 days of varied stress (p26899341). Rat compounds ocimumoside A/B lowered stress-raised corticosterone (p17850106, p22455995). Human: in an 8-week trial of 100 stressed adults, a 250 mg/day extract was linked to lower hair cortisol and lower salivary cortisol after a lab stress test than placebo (p36185698); in a 30-day trial of healthy volunteers, salivary cortisol fell over time in the extract group only, but the between-group difference was not significant (p26571987). A systematic review of HPA-axis trials found the human effect of most plants unclear (p33650944). ^{38 34 4 50 72 51}	Controlled trial
Cyclooxygenase (COX-1/COX-2) blocking	PTGS1 (COX-1), PTGS2 (COX-2)	Test tube: eugenol, rosmarinic acid, apigenin and other isolated leaf compounds blocked COX-1 and COX-2; eugenol blocked 97% of COX-1 at 1000 micromolar, and effects were described as comparable to ibuprofen, naproxen and aspirin at 10, 10 and 1000 micromolar (p10782484). These are concentrations in a dish; human blood levels of these compounds after tulsi are not known. ⁴²	Laboratory research
Lipoxygenase and the arachidonic-acid (inflammation) pathway	ALOX5 (5-LOX) and COX together (dual inhibition)	Animal: tulsi SEED oil (not leaf) reduced paw swelling caused by prostaglandin E2, leukotriene and arachidonic acid in rats; the authors credited linolenic acid for blocking both COX and LOX routes, and reviewers described the oil as a dual inhibitor (p10356964, p17569280). Seed oil is a different product from leaf tea or leaf extract. No leaf-extract LOX measurement in humans was found. ^{81 83}	Animal research
Antioxidant action	General redox balance; glutathione, SOD, catalase, lipid peroxidation in rat brain	Test tube: eugenol, rosmarinic acid, cirsilineol and others scavenged free radicals at 10 micromolar (p10782484). Animal: in rats under chronic stress, ocimumosides A and B restored brain glutathione, superoxide dismutase and catalase and reduced lipid peroxidation, with an effect comparable to melatonin (p22455995). Human antioxidant outcomes were not read for this file. Antioxidant results in a dish or in rats are not proof of a health benefit. ^{42 4}	Laboratory research
Immune cells and cytokines	IFNG (interferon-gamma), IL4; NK cells, T-helper cells	Human: in a double-blind crossover trial in 24 healthy volunteers (22 analysed), 300 mg of ethanolic leaf extract on an empty stomach for 4 weeks raised interferon-gamma (p=0.039), interleukin-4 (p=0.001), T-helper cell percentage (p=0.001) and NK-cell percentage (p=0.017) compared with placebo (p21619917). Small, healthy-people trial; the clinical meaning (for example fewer infections) was not tested. ⁵⁵	Controlled trial
Brain chemistry (noradrenaline, dopamine, serotonin) under stress	Monoamine systems (NA, DA, 5-HT)	Animal: chronic stress lowered noradrenaline, dopamine and serotonin in three rat brain areas; ocimumosides A and B (40 mg/kg) reversed most of these changes (p22455995). No human brain-chemistry data were found. Human mood and thinking results are in the benefits files. ⁴	Animal research
Cannabinoid receptor CB2 (caryophyllene, from outside tulsi)	CNR2 (CB2)	Lab/animal: purified (E)-beta-caryophyllene bound CB2 (Ki 155 nM), lowered inflammatory chemicals in human blood cells and reduced paw swelling in mice (5 mg/kg by mouth) that have CB2 but not in mice lacking it (p18574142). Tulsi's oil contains 27.8 to 49.0% caryophyllene in four samples (p39073007), but no experiment ties tulsi's own effects to CB2. ^{30 31}	Animal research
Drug-processing liver enzymes (cytochrome P450)	CYP1A2, CYP2C9, CYP2D6, CYP3A4	Test tube: purified eugenol at 1, 10 and 100 micromolar reduced the activity of these four enzymes in human liver microsomes (CYP2D6 IC50 11.09 micromolar; CYP3A4 IC50 13.48 micromolar) (p38841106). This is a signal for possible herb-drug interactions with high eugenol exposure, not a tested interaction with tulsi tea or capsules in people. Interactions are detailed in the safety file. ⁷	Laboratory research
Plant-adaptogen network summary	HPA axis; Hsp70; NF-kB; JNK; FOXO (as a group of adaptogens)	A 2026 narrative review of seven adaptogens including O. tenuiflorum describes shared pathway effects (HPA regulation, heat-shock protein induction, NF-kB, JNK and FOXO signalling) across the group. The abstract does not separate what is shown for tulsi from the others, so it is listed here only as background and not as a tulsi finding. ⁸⁶	Pharmacological theory

Absorption, metabolism and elimination

Absorption: No human absorption study of tulsi leaf, tea or extract was found. For single compounds from other sources: eugenol reached peak blood levels quickly after an oral dose in rats and had a long half-life of 14.0 h in plasma and 18.3 h in blood at 40 mg/kg (p17321520). Eugenol from a curry dish appeared in the urine of 18 breastfeeding women with a peak 1.5 h after the meal, up to 6 micrograms per gram creatinine (p37953385). Rosmarinic acid from a perilla extract (200 mg RA) was absorbed by 6 healthy men; free rosmarinic acid peaked in blood at about 0.5 h (p15309457).
Distribution: No human tissue-distribution data for tulsi compounds were found. The rat study measured blood and plasma only (p17321520).
Metabolism: Eugenol is conjugated: glucuronide forms were 77 times higher in urine after enzyme treatment in a six-person food study (p37953385). Rosmarinic acid is conjugated (glucuronide/sulfate) and methylated, and part is broken down to caffeic and ferulic acids, mostly present as conjugates (p15309457). These two studies used a curry dish and a perilla extract; tulsi itself was not tested. Eugenol also reduced several CYP enzymes in human liver microsomes (p38841106).
Elimination: After the perilla extract, about 6.3% of the dose appeared in urine as rosmarinic acid and related products, about 75% of it within 6 hours (p15309457). Eugenol's blood half-life in rats was 14 to 18 hours (p17321520). Ursolic acid given by vein as nano-liposomes (not by mouth and not from tulsi) showed a linear dose-response and no build-up over 14 days in 8 patients (p23319864; the analytical paper is p21169069).
Bioavailability: Not measured for tulsi in people. Ursolic acid and other triterpenes are known in general to dissolve poorly in water, and most ursolic-acid delivery research uses nano-formulations to get around that (p23319864); that statement is general background and not a measurement of tulsi. The size of the flavone and rosmarinic acid share that reaches blood from tulsi is unknown.

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Isolated compounds versus whole extracts

Tulsi is a mix of essential-oil compounds (eugenol, caryophyllene, elemene), triterpenes (ursolic and oleanolic acid), flavones (apigenin, luteolin and their glycosides) and phenolic acids (rosmarinic acid). The only human tulsi trials used whole leaf or leaf extracts (p36185698, p26571987, p21619917, p19253862, p8880292), so which compound carries the effect is unknown. In the lab, several different leaf compounds blocked COX enzymes, so no single one explains it (p10782484). For cortisol the lab data point to ursolic acid and extract together (p26899341), while in rats two newly named glycosides, ocimumosides A and B, worked but ocimarin and apigenin glucuronide did not (p17850106, p22455995). Content differs by type: green tulsi had more ursolic acid, black (Krishna) had oleanolic acid and the green type did not (p17225591), and purple types may carry more methyl eugenol (p38520476). So 'tulsi' means different things in tea, capsule and essential oil, and purified compounds (eugenol, ursolic acid) should not be treated as the same thing as the leaf or its extract.

Nutritional composition

Tulsi is used as a herb, tea and flavouring, so a nutrient table is not very meaningful and no per-100 g vitamin or mineral values were verified here. The oil makes up under 0.5% of fresh herb in the green holy basils tested in one study (p38202372). Seed oil contains alpha-linolenic acid (an omega-3 fat) and is a separate product from the leaf (p17569280).

20benefits and uses looked at

96studies and sources checked

Low certaintybest evidence rating found

23lab markers tracked in trials

7 low certainty6 very low certainty7 not enough evidence

What was looked at

The 20 benefits and uses checked for Holy Basil (Tulsi), each with how strong the evidence is. Tap one to open it.

StressLow certainty
Anxiety and generalized anxiety disorderVery low certainty
Mood and depressionVery low certainty
Thinking, attention and memoryVery low certainty
SleepLow certainty
Fatigue and burnoutVery low certainty
Blood sugar and type 2 diabetesLow certainty
Cholesterol and blood fatsLow certainty
Blood pressureVery low certainty
Metabolic syndrome and body weightVery low certainty
Immune markersLow certainty
Gum health and dental plaque (mouthwash, toothpaste, gel)Low certainty
Mouth bacteria, tooth decay germs and bad breathLow certainty
Fighting germs and infectionsNot enough evidence
Cough, asthma and COPDNot enough evidence
Skin and acneNot enough evidence
Fertility, sperm and PCOSNot enough evidence
Exercise performance and physical fatigueNot enough evidence
Inflammation and uric acidNot enough evidence
ThyroidNot enough evidence

Lab markers tracked in the studies

CortisolPerceived Stress Scale (PSS)Stress symptom rating scaleAnxiety rating scalesAthens Insomnia Scale (AIS)Attention and memory test speed (Sternberg, Stroop) and P300 latencyFasting blood glucoseAfter-meal (postprandial) blood glucoseHbA1c (long-term blood sugar)TriglyceridesLDL cholesterolHDL cholesterolTotal cholesterolInsulin and insulin resistanceBlood pressureInterferon-gammaInterleukin-4Natural killer (NK) cellsDental plaque indexGum (gingival) inflammation indexSalivary Streptococcus mutansSerum uric acidLiver enzymes (SGPT/ALT and SGOT/AST)

What is Holy Basil (Tulsi) good for?

The main proposed uses and how strong the human evidence is for each. Nothing is rated above low certainty.

StressLow certaintyHoly basil extracts have been tested for stress in a few small to medium trials. Two placebo-controlled trials of branded extracts (OciBest and Holixer) found lower stress scores, and the newer one also found lower hair cortisol. Both were funded or linked to the extract makers, and there are few independent trials, so confidence is low. SleepLow certaintyHoly basil extracts were linked to better self-rated sleep in two stress trials. The 2022 trial found a better insomnia score than placebo, but the Fitbit results are not reported in the abstract, and the authors say the sleep findings need confirming with objective measures. Evidence is low. Anxiety and moodVery low certaintyThere is no good human trial of holy basil for diagnosed anxiety or depression. One small uncontrolled hospital study in 35 people with generalized anxiety disorder found lower anxiety after 60 days of a leaf extract, but with no comparison group it cannot show the herb did it. Mood was also measured in the stress trials, but the abstracts give little detail. Evidence is very thin, and most of the mood findings come from animals. Thinking, attention and memoryVery low certaintyOne small placebo-controlled study in healthy adults found faster reaction times and fewer errors on attention and memory tests after 30 days of a holy basil leaf extract. It has not been repeated, the abstract gives no group size, and the evidence is very limited. Animal studies show brain-protective effects, which are not proof for people. Tiredness and exercise performanceVery low certaintyPeople with stress symptoms who took the extract OciBest reported less frequent exhaustion than on placebo, but no trial was designed to test holy basil for fatigue or burnout. One small trial reported in a review (30 healthy young adults, a snack bar with tulsi extract for 2 weeks) found better physical performance and less fatigue than a control bar; we could not read the original, so it is a hint only. Blood sugar and type 2 diabetesLow certaintySeveral small human trials, mostly from India and many decades old, found lower fasting and after-meal blood sugar when people with type 2 diabetes took holy basil (tulsi) leaf powder or extract. The best-described trial found fasting blood sugar about 21 mg/dl lower than on placebo. The 2017 review that gathered the human studies rated only a minority as good quality, so this is promising but low-certainty. It is not a replacement for diabetes medicine. Cholesterol and blood fatsLow certaintyA handful of small trials report better blood fats (triglycerides, LDL, HDL) with tulsi. The one trial we could read (30 overweight young adults, 250 mg of leaf extract twice a day for 8 weeks) found better triglycerides, LDL and HDL than at the start, but only HDL was clearly better than the untreated group. Evidence is low-certainty. Blood pressure, weight and metabolic syndromeVery low certaintyA few very small, old trials of fresh tulsi juice or leaf powder reported lower blood pressure in people with high blood pressure or metabolic syndrome. The details could not be checked, and one trial was in women with low blood pressure. One pilot in 30 overweight young adults found a lower BMI, insulin and insulin resistance after 8 weeks, but there was no placebo group. There is not enough reliable evidence to say tulsi lowers blood pressure or helps weight. Immune markersLow certaintyIn one small crossover trial of 22 healthy adults, 300 mg of a tulsi leaf extract a day for 4 weeks raised some immune signals in blood tests (interferon-gamma, interleukin-4, T-helper cells and NK cells) compared with placebo. That shows the immune system was changed, not that people got sick less often, and no trial has counted colds or infections with tulsi alone. Gum health, plaque, mouth germs and bad breathLow certaintyDental trials from India tested tulsi mouthwash, toothpaste and gum gels. In most, tulsi lowered plaque and gum inflammation and was often about as good as chlorhexidine (the standard medicated rinse) after a month. Tulsi rinses also lowered levels of Streptococcus mutans (a germ linked to cavities) in several short trials, and a 15-day trial found it helped bad breath, though less than chlorhexidine or hydrogen peroxide. The trials are small and short, and the germ counts are not proof of fewer cavities. Germs, infections, cough and asthmaNot enough evidenceIn the lab, tulsi oils and extracts kill many bacteria and fungi. For infections in the body there is almost no usable human evidence, only small, old open trials listed in a review. Tulsi is a traditional cough and asthma remedy in India, but the only human study listed is a 1983 open trial of 20 people with asthma; the rest is from rodents or cell dishes. It should not be used to treat an infection, and we cannot say it helps cough, asthma or COPD. Skin and acneNot enough evidenceTulsi is used in skin care and has anti-bacterial and anti-inflammatory activity in the lab, but we found no human trial of tulsi for acne or any skin condition in the databases searched. Inflammation and uric acidNot enough evidenceThe authors of the 2017 review suggest tulsi's many effects may share inflammation as a root, and tulsi lowers inflammation markers in lab and animal work. In people, evidence is thin: one 200-person trial in gout (a tincture) reported lower uric acid, and tulsi mouthwash lowered some inflammation markers in gum fluid. No trial measured CRP or joint pain in arthritis. Fertility, sperm and PCOSNot enough evidenceNo human trial has tested tulsi for fertility, sperm quality or polycystic ovary syndrome. A few rat studies suggest tulsi protected testes from drug damage or eased PCOS-like changes. There is not enough to say anything about people. ThyroidNot enough evidenceNo human trial tested tulsi for an underactive or overactive thyroid. The only thyroid-related trial gave holy basil tea to people having radioactive iodine treatment after thyroid cancer surgery and looked at anxiety and mouth and salivary-gland side effects, not thyroid function.

Benefits, one by one

Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.

Stress

Low certainty

Holy basil extracts have been tested for stress in a few small to medium trials. Two placebo-controlled trials of branded extracts (OciBest and Holixer) found lower stress scores, and the newer one also found lower hair cortisol. Both were funded or linked to the extract makers, and there are few independent trials, so confidence is low.

7 studiesBranded standardised extracts (OciBest 1200 mg of actives per day for…

Studies, doses and limits

What the trials found

Saxena 2012 (OciBest, 150 adults, 1200 mg of actives per day, 6 weeks) found total stress-symptom scores fell more than on placebo (P <= 0.05), described by the authors as 39% more improvement. Lopresti 2022 (Holixer extract, 100 adults, 125 mg twice daily, 8 weeks) found a larger fall in Perceived Stress Scale scores than placebo (p = 0.003), lower hair cortisol at week 8 (p = 0.025), and, after a lab stress test, lower salivary cortisol (p = 0.001), salivary amylase (p = 0.001), blood pressure (systolic p = 0.010, diastolic p = 0.025) and rated stress (p < 0.001). Sampath 2015 (ethanolic leaf extract, 300 mg a day, 30 days, healthy volunteers) found salivary cortisol and anxiety scores improved over time in the extract group only, but the difference from placebo was not significant. A 2026 trial (186 adults, 60 days) of a three-herb formula of Rhodiola, holy basil and Schisandra found lower Perceived Stress Scale scores than placebo (p < 0.0001), but holy basil cannot be credited alone. The 2017 systematic review of 24 human tulsi studies (Jamshidi and Cohen) reported favourable results on psychological stress, but it was not a meta-analysis and all studies were reported as positive. A 2022 systematic review of stress-hormone trials (Lopresti) listed holy basil among 26 plants and said the effect of most plants on stress hormones in people was unclear.

Results

Both main extract trials were positive on stress scores. The 2022 trial adds objective stress-hormone measures.

Effect sizes as reported

Saxena 2012: 1.6 times (39%) more improvement than placebo, P <= 0.05. Lopresti 2022: PSS p = 0.003; hair cortisol p = 0.025 (effect sizes not in the abstract).

Why this rating

Few trials, both positive trials used branded extracts and have ties to the makers, no independent replication, no pooled analysis, and the reviews rely on mostly small and lower-quality studies. No formal GRADE rating was found.

Form and dose studied

Branded standardised extracts (OciBest 1200 mg of actives per day for 6 weeks; Holixer 125 mg twice daily for 8 weeks) and a leaf extract (300 mg a day for 30 days). No trial of tea or plain leaf powder for stress was found among those read. Results from one preparation should not be assumed for another.

Who was studied

Adults with general stress or high stress, aged 18 to 65 in the Holixer trial; healthy volunteers in Sampath.

Limits

Mostly manufacturer-linked trials; stress is mostly self-rated; the cortisol results come from one trial and were not repeated; the 2022 stress-hormone review gives no holy-basil-specific result.

Why researchers looked

Holy basil is sold mainly as a stress herb, so stress is its main studied use in people.

Traditional use

Holy basil (tulsi) is a sacred plant in India and a long-used Ayurvedic herb, traditionally taken as a tea or leaf preparation and called an adaptogen, a herb said to help the body cope with stress.

Proposed mechanism Preliminary mechanism

Lab and animal work suggests holy basil extract may calm the body's stress-hormone system: in cell tests a standardised extract (Holixer) reduced cortisol release and blocked the CRF1 stress receptor, and in rodents it blocked a stress-induced rise in corticosterone (Gowda 2023, written by the extract maker). This has not been shown to be how it works in people.

A proposed mechanism does not show that the effect happens in people.

No serious side effects reported in the trials read; trials were short (up to 8 weeks). See the safety file for full safety information.

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Anxiety and generalized anxiety disorder

Very low certainty

One small uncontrolled hospital study in 35 people with generalized anxiety disorder found lower anxiety after 60 days of a leaf extract, but with no comparison group it cannot show the herb did it. Placebo-controlled stress trials add only indirect hints. There is no good trial of holy basil for diagnosed anxiety.

4 studiesLeaf extract 500 mg twice daily for 60 days (Bhattacharyya); leaf ext…

Studies, doses and limits

What the trials found

Bhattacharyya 2008 gave 35 people with generalized anxiety disorder a leaf extract, 500 mg twice daily, and assessed them at days 0, 30 and 60. Anxiety, and the related stress and depression, fell (p<0.001), and attention and willingness to adjust improved. The abstract describes no placebo or comparison group. Sampath 2015 (healthy adults, 300 mg ethanolic leaf extract a day for 30 days) found State-Trait Anxiety Inventory scores improved over time in the extract group only, but the difference between groups was not significant. In the 2026 three-herb formula trial (Rhodiola, holy basil, Schisandra; 186 adults) anxiety scores improved versus placebo (p = 0.0004), but holy basil cannot be separated out. The Cohen 2014 narrative review cites mostly animal studies for anxiety-reducing effects.

Results

One uncontrolled study improved; one placebo-controlled study improved over time but not versus placebo; one formula trial improved but is not specific to holy basil.

Effect sizes as reported

Bhattacharyya 2008: p<0.001 vs baseline (no scale scores in abstract).

Why this rating

The only study in diagnosed anxiety had no placebo group, was small and does not describe the preparation in detail. The other results are indirect.

Form and dose studied

Leaf extract 500 mg twice daily for 60 days (Bhattacharyya); leaf extract 300 mg daily for 30 days (Sampath). No trial of tea or leaf powder for anxiety was found.

Who was studied

People with generalized anxiety disorder (35); healthy adults (Sampath).

Limits

Not a controlled trial; very small; published in a small journal; no independent replication. Holy basil should not replace treatment for anxiety disorders.

Why researchers looked

Holy basil is traditionally seen as calming, and animals given it show anxiety-reducing behaviour in many experiments, so anxiety is a natural thing to test.

Traditional use

Holy basil (tulsi) is a sacred plant in India and a long-used Ayurvedic herb, traditionally taken as a tea or leaf preparation and called an adaptogen, a herb said to help the body cope with stress.

Proposed mechanism Preliminary mechanism

Mostly from animal and lab work, which is not covered in detail here. The likeliest ideas involve the stress-hormone system (see stress) and antioxidant effects in brain tissue; none is proven in people.

A proposed mechanism does not show that the effect happens in people.

Do not stop prescribed anxiety medicine to try holy basil. See the safety file for interactions.

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Mood and depression

Very low certainty

There is no good human trial of holy basil for depression. Mood was measured in trials of holy basil for stress, but the abstracts give little detail. Evidence is very thin and mostly from animals.

5 studiesLeaf extract 500 mg twice daily (Bhattacharyya); three-herb formula (…

Studies, doses and limits

What the trials found

No randomised trial in people with depression was found among those read. Bhattacharyya 2008 (35 people with generalized anxiety disorder, leaf extract 500 mg twice daily, 60 days, no comparison group) reported that depression scores fell alongside anxiety (p<0.001). Lopresti 2022 measured mood with the Profile of Mood States, but the abstract does not report the result. In the 2026 three-herb formula trial (Rhodiola, holy basil and Schisandra, 186 adults) mood dysregulation improved versus placebo (p = 0.0454), but holy basil cannot be credited alone.

Results

Mood effects were small side findings in uncontrolled or multi-herb studies.

Effect sizes as reported

Only p-values; no effect sizes available in the abstracts.

Why this rating

No trial was designed for depression; findings come from an uncontrolled study and a three-herb formula.

Form and dose studied

Leaf extract 500 mg twice daily (Bhattacharyya); three-herb formula (2026).

Who was studied

People with anxiety disorder or high stress; none with diagnosed depression.

Limits

No trial in people with depression; mood result in Lopresti 2022 not seen (full text not read).

Why researchers looked

Holy basil is traditionally used for low mood and mental fatigue, and animal studies report antidepressant-like effects.

Traditional use

Holy basil (tulsi) is a sacred plant in India and a long-used Ayurvedic herb, traditionally taken as a tea or leaf preparation and called an adaptogen, a herb said to help the body cope with stress.

Proposed mechanism Preliminary mechanism

Animal studies are said to show antidepressant-like effects, and the Holixer extract reduced immobility time in the rat forced swim test (Gowda 2023). These are animal tests and do not show a benefit in people with depression.

A proposed mechanism does not show that the effect happens in people.

Do not use as a replacement for depression treatment. See the safety file for interactions with antidepressants.

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Thinking, attention and memory

Very low certainty

One small placebo-controlled study in healthy adults found faster reaction times and fewer errors on attention and memory tests after 30 days of a holy basil leaf extract. It has not been repeated, the abstract gives no group size, and the evidence is very limited. Animal studies show brain-protective effects, which are not proof for people.

4 studiesEthanolic leaf extract 300 mg daily for 30 days (Sampath); OciBest 12…

Studies, doses and limits

What the trials found

Sampath 2015 gave healthy adult volunteers a 300 mg capsule of ethanolic holy basil leaf extract or placebo daily for 30 days. Compared with placebo, the extract group improved more in reaction time and error rate on the Sternberg memory test and in reaction time on neutral and interference Stroop tasks (and error rate on the interference task). P300 latency, an electrical brain-response speed measure, was significantly better than placebo. The placebo group also improved on the tasks, but stopped improving after day 15. Saxena 2012 (OciBest, 150 adults) found self-rated forgetfulness fell more than on placebo (P <= 0.05). A 2023 trial (128 older adults, 90 days) of a ten-herb blend that includes holy basil found faster task speed but memory deficits, which the authors say may be due to unequal randomisation; holy basil cannot be credited or blamed for this.

Results

Faster reaction times and fewer errors in healthy adults on one small trial; self-rated forgetfulness improved in a stress trial.

Effect sizes as reported

Specific values not given in the abstracts.

Why this rating

Only one small trial in healthy people, group size not stated in the abstract, and no replication. Others are indirect or multi-herb.

Form and dose studied

Ethanolic leaf extract 300 mg daily for 30 days (Sampath); OciBest 1200 mg of actives a day (Saxena).

Who was studied

Healthy adults (Sampath); stressed adults (Saxena). None in people with dementia or mild cognitive impairment.

Limits

Single small trial; healthy volunteers only; the practice effect on repeat testing; no trial in memory problems or dementia.

Why researchers looked

Holy basil is traditionally taken to sharpen the mind, and lab studies show it may protect brain cells from damage.

Traditional use

Holy basil (tulsi) is a sacred plant in India and a long-used Ayurvedic herb, traditionally taken as a tea or leaf preparation and called an adaptogen, a herb said to help the body cope with stress.

Proposed mechanism Animal research

In animal and cell studies, Ocimum extracts raise the brain's own antioxidant enzymes and reduce beta-amyloid and tau (Vasincu 2025 review, covering holy and sweet basil). This is lab work and does not show a benefit for memory in people.

A proposed mechanism does not show that the effect happens in people.

No safety concerns reported in these trials; short duration.

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Sleep

Low certainty

Holy basil extracts were linked to better self-rated sleep in two stress trials. The 2022 trial found a better insomnia score than placebo, but the Fitbit results are not reported in the abstract, and the authors say the sleep findings need confirming with objective measures. Evidence is low.

3 studiesHolixer 125 mg twice daily for 8 weeks; OciBest 1200 mg of actives pe…

Studies, doses and limits

What the trials found

Lopresti 2022 (Holixer extract, 100 stressed adults, 125 mg twice daily, 8 weeks) found a larger improvement than placebo in Athens Insomnia Scale scores (p = 0.025); the authors say sleep results were subjective and objective sleep measures are needed. Saxena 2012 (OciBest, 150 adults, 6 weeks) found self-rated recent sleep problems fell more than on placebo (P <= 0.05). The 2026 three-herb formula trial (Rhodiola, holy basil, Schisandra) improved PSQI (p = 0.0008) and restorative sleep (p < 0.0001) versus placebo, but holy basil cannot be credited alone.

Results

Better self-rated sleep in two single-extract trials; objective sleep not reported in the abstract.

Effect sizes as reported

p-values only (AIS p = 0.025 in Lopresti 2022).

Why this rating

Two trials with branded extracts and ties to makers; sleep was a secondary outcome; self-rated. Rated low rather than very-low because two separate trials point the same way.

Form and dose studied

Holixer 125 mg twice daily for 8 weeks; OciBest 1200 mg of actives per day for 6 weeks.

Who was studied

Adults with stress; none selected for insomnia.

Limits

Sleep was secondary; self-reported; no trial in people with insomnia; objective Fitbit results not seen in the abstract.

Why researchers looked

Poor sleep goes with stress, and a stress-reducing herb may help sleep indirectly.

Traditional use

Holy basil (tulsi) is a sacred plant in India and a long-used Ayurvedic herb, traditionally taken as a tea or leaf preparation and called an adaptogen, a herb said to help the body cope with stress.

Proposed mechanism Pharmacological theory

No clear mechanism for sleep has been shown. If the herb lowers stress arousal (see stress), sleep could improve as a result; this is a theory.

A proposed mechanism does not show that the effect happens in people.

No sleepiness or serious effects reported; trial duration was short.

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Fatigue and burnout

Very low certainty

The only direct finding is that people with stress symptoms taking OciBest reported less frequent exhaustion than on placebo. No trial was designed to test holy basil for fatigue or burnout, so evidence is very limited.

3 studiesOciBest 1200 mg of actives per day for 6 weeks.

Studies, doses and limits

What the trials found

In Saxena 2012 (OciBest, 150 adults with general stress, 1200 mg of actives per day, 6 weeks), the symptom 'frequent feeling of exhaustion' decreased significantly more than on placebo (P <= 0.05). Fatigue was one item among several stress symptoms, not a main outcome. The 2026 three-herb formula trial (Rhodiola, holy basil, Schisandra) reported reduced fatigue in its conclusion but the abstract does not give the fatigue figure, and holy basil cannot be credited alone.

Results

One item of a stress symptom scale improved.

Effect sizes as reported

P <= 0.05 for the exhaustion item; no effect size in the abstract.

Why this rating

One symptom item in one manufacturer-linked trial; no fatigue-focused trial or burnout trial.

Form and dose studied

OciBest 1200 mg of actives per day for 6 weeks.

Who was studied

Adults with general stress.

Limits

Self-rated item; not a validated fatigue scale; no trial in burnout or chronic fatigue.

Why researchers looked

Holy basil is used in Ayurveda as a tonic for tiredness related to stress.

Traditional use

Holy basil (tulsi) is a sacred plant in India and a long-used Ayurvedic herb, traditionally taken as a tea or leaf preparation and called an adaptogen, a herb said to help the body cope with stress.

Proposed mechanism Animal research

Animal tests show greater swimming endurance after holy basil extract (Gowda 2023, mice), which has been used to suggest an anti-fatigue effect; this does not show fatigue relief in people.

A proposed mechanism does not show that the effect happens in people.

No adverse events reported in this trial.

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Blood sugar and type 2 diabetes

Low certainty

Several small human trials, mostly from India and many decades old, found lower fasting and after-meal blood sugar when people with type 2 diabetes took holy basil (tulsi) leaf powder or extract. The best-described trial found fasting blood sugar about 21 mg/dl lower than on placebo. The 2017 review that gathered the human studies rated only a minority as good quality, so this is promising but low-certainty. It is not a replacement for diabetes medicine.

7 studiesLeaf powder 1 to 2.5 g a day, capsules totalling 3 g a day, or 300 mg…

Studies, doses and limits

What the trials found

The 2017 systematic review (Jamshidi and Cohen) found blood sugar was the most common outcome, measured in 8 of 24 human studies, and all of those reported lower sugar. The most fully described trial (Agrawal 1996, single-blind crossover, people with type 2 diabetes) gave holy basil leaves against placebo leaves: fasting blood sugar fell by 21.0 mg/dl (17.6%) and after-meal sugar by 15.8 mg/dl (7.3%); urine sugar showed the same trend. Other studies listed in the review table, which could not be independently located and read for this profile, include: Somasundaram 2012 (60 adults, tulsi 300 mg a day plus glibenclamide versus glibenclamide alone for 13 weeks, with lower fasting and after-meal sugar and HbA1c), Gandhi 2016 (40 men, 3 g of leaf capsules a day for about 6.5 weeks), Venkatesan 2015 (30 adults, 2 g a day for 2 weeks), Rai 1997 (27 adults, 1 g of leaf powder a day for 4 weeks, uncontrolled) and Dineshkumar 2010 (40 adults, 8 weeks, compared with water). I did not find a newer, larger, well-run trial after the review.

Results

Lower fasting and after-meal blood sugar in every trial reported, with HbA1c lower in the trials that measured it (per the review table).

Effect sizes as reported

Agrawal 1996: fasting glucose -21.0 mg/dl (95% CI -31.4 to -11.2, p<0.001); after-meal glucose -15.8 mg/dl (95% CI -27.0 to -5.6, p<0.02). Other trials: no numbers available to this profile.

Why this rating

Small trials (27 to 90 people), short (2 to 13 weeks), mostly from India, many with no placebo or only single-blinding, and the review itself says only 7 of 24 studies were high quality and that benefit may be overestimated. No pooled meta-analysis. The rating is the compiler's, informed by the review's own caution.

Form and dose studied

Leaf powder 1 to 2.5 g a day, capsules totalling 3 g a day, or 300 mg of leaf extract with a diabetes drug; dose and form varied widely and cultivar was usually not stated.

Who was studied

Adults with type 2 diabetes (40 to 65 years), India.

Limits

No trial longer than 13 weeks. Hard outcomes such as eye, kidney or heart complications were not studied. Whether the effect is large enough to matter on top of modern diabetes care is unknown. Products and doses cannot be compared.

Why researchers looked

Type 2 diabetes is very common and people look for food-based add-ons. Tulsi leaves have long been used in Ayurveda, and lab and animal studies found blood-sugar lowering, which led to the human trials.

Traditional use

Tulsi is a sacred plant in India and has been used daily as a leaf, tea or juice. Use for sugar disorders is mentioned in Ayurvedic tradition; the 2017 review says the trials reinforce those traditional uses.

Proposed mechanism Preliminary mechanism

The review suggests the leaf compound eugenol may lower blood sugar in two ways: by stopping glucose from binding to blood proteins and by slowing the breakdown of starch into sugar. This comes from lab work and is a suggestion, not shown in these trials.

A proposed mechanism does not show that the effect happens in people.

If you take diabetes medicine, tulsi on top could in theory push sugar lower; tell your doctor or pharmacist before trying it. See the safety file for more.

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Cholesterol and blood fats

Low certainty

A handful of small trials report better blood fats (triglycerides, LDL, HDL) with tulsi. The one trial I could read (30 overweight young adults, 250 mg of leaf extract twice a day for 8 weeks) found better triglycerides, LDL and HDL than at the start, but only HDL was clearly better than the untreated group. Evidence is low-certainty.

7 studies250 mg of leaf extract capsule twice a day (8 weeks); 5 mL of aqueous…

Studies, doses and limits

What the trials found

Satapathy 2017 (30 young overweight or obese adults in India; open-label, no placebo; 16 took a 250 mg leaf extract capsule twice daily for 8 weeks and 14 had no treatment): in the tulsi group, triglycerides (p=0.019), LDL (p=0.001), HDL (p=0.001), VLDL (p=0.019) and BMI (p=0.005) improved; against the untreated group, only the HDL gain was significant (p=0.037). Liver enzymes did not change. In Agrawal 1996, total cholesterol showed only a mild reduction. The 2017 review table lists further small studies that reported better lipids but that I could not read: Devra 2012 (100 adults with metabolic syndrome, aqueous leaf preparation 5 mL twice daily for 12 weeks), Dineshkumar 2010 (40 adults with type 2 diabetes, 8 weeks versus water), Rai 1997 and a small healthy-volunteer trial where lipids fell in 6 people. The review counted 6 studies with lipids as an outcome. Total cholesterol was the one lipid the review table says did not improve in the Satapathy trial.

Results

Mostly better triglycerides, LDL and HDL in small, short studies; total cholesterol change was mild or absent.

Effect sizes as reported

p-values only in the abstracts (e.g., HDL vs untreated p=0.037); no effect sizes or confidence intervals available.

Why this rating

Small, short, often no placebo or blinding; abstract-level data only; no pooled analysis; one hint (HDL) survived comparison with the control group. Compiler's rating.

Form and dose studied

250 mg of leaf extract capsule twice a day (8 weeks); 5 mL of aqueous leaf preparation twice daily (12 weeks); other forms listed in the review.

Who was studied

Overweight/obese young adults; adults with metabolic syndrome or type 2 diabetes; India.

Limits

A better lab number is not fewer heart attacks. No trial followed heart outcomes. Diet and exercise changes were not controlled in the abstract.

Why researchers looked

Blood fats are a main risk factor for heart disease and often go along with high blood sugar and weight.

Traditional use

Tulsi is described in Ayurveda as a heart-supportive herb; modern lipid trials followed lab and animal findings.

Proposed mechanism Animal research

Animal studies found tulsi lowered cholesterol and fats in diabetic and high-fat-diet animals; how this might work in people is not established.

A proposed mechanism does not show that the effect happens in people.

Satapathy found no significant change in liver enzymes; the review reported mild nausea in one study. See the safety file.

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Blood pressure

Very low certainty

A few very small, old trials of fresh tulsi juice or leaf powder reported lower blood pressure in people with high blood pressure or metabolic syndrome. The details could not be checked, and one trial was in women with low blood pressure. There is not enough reliable evidence to say tulsi lowers blood pressure.

5 studiesFresh tulsi juice 30 mL once or twice a day; 2 g leaf powder daily; 5…

Studies, doses and limits

What the trials found

Six studies in the 2017 review measured blood pressure. From its table: Sarvaiya 1986 (two small trials, 20 and 16 adults with hypertension, fresh juice of about 75% tulsi, 30 mL a day for 10 days in a crossover trial and 30 mL twice a day for 12 days versus coloured water; blood pressure fell, by about 25% in the second); Devra 2012 (100 adults with metabolic syndrome, aqueous leaf, 12 weeks, blood pressure improved); Kochhar 2009 (90 men, 2 g of leaf powder a day for 12 weeks, blood pressure improved). Bhargava 2013 (50 young women with LOW blood pressure, juice of 15 leaves, 4 weeks) also reported a change in blood pressure; the review does not state the direction. I found no later trial.

Results

Lower blood pressure reported in the high-blood-pressure and metabolic syndrome trials, with no usable numbers.

Effect sizes as reported

Not available; the review table gives no mmHg values (one summary says about 25% lower).

Why this rating

Tiny and old trials, short follow-up, no numbers, details unverifiable, one trial in a low-blood-pressure group. Compiler's rating.

Form and dose studied

Fresh tulsi juice 30 mL once or twice a day; 2 g leaf powder daily; 5 mL aqueous preparation twice daily.

Who was studied

Adults with hypertension or metabolic syndrome; India.

Limits

Only the review summary was read; no mmHg values; very short; not tested together with blood pressure medicines.

Why researchers looked

Tulsi is traditionally linked to heart health and was tested alongside the sugar and lipid work.

Traditional use

Ayurvedic texts describe tulsi as a heart tonic; no specific modern blood pressure use is established.

Proposed mechanism Pharmacological theory

No mechanism for blood pressure in people has been shown. Animal work suggests a heart-protective effect, which is a theory.

A proposed mechanism does not show that the effect happens in people.

If you take blood pressure medicine, ask your doctor first: in theory the effects could add up. If you already have low blood pressure, avoid assuming tulsi is harmless. See the safety file.

^{37 75 25 45 12}

Metabolic syndrome and body weight

Very low certainty

Metabolic syndrome is a cluster of high blood sugar, blood pressure, blood fats and waist size. Tulsi has been tried in only a few small trials. One pilot in 30 overweight young adults found a lower BMI, insulin and insulin resistance in the tulsi group after 8 weeks, but there was no placebo. A larger 100-person trial in metabolic syndrome is listed in a review but I could not read it.

4 studies250 mg of leaf extract capsule twice a day for 8 weeks; 5 mL aqueous …

Studies, doses and limits

What the trials found

Satapathy 2017 (30 overweight/obese young adults, 250 mg leaf extract twice a day for 8 weeks versus no treatment): in the tulsi group BMI (p=0.005), plasma insulin (p=0.021) and insulin resistance (p=0.049) improved. The review table also lists Devra 2012 (100 adults aged 40+ with metabolic syndrome, 12 weeks, improved lipids, fasting sugar and blood pressure) and Kochhar 2009 (90 men with type 2 diabetes or metabolic syndrome, 12 weeks).

Results

Small improvements in BMI, insulin and insulin resistance in one open-label pilot; improvements reported in two further trials that could not be read.

Effect sizes as reported

p-values only: BMI p=0.005, insulin p=0.021, insulin resistance p=0.049 (within the tulsi group).

Why this rating

Only a 30-person pilot with no placebo or blinding was read; the larger trials are known only through a review table. Compiler's rating.

Form and dose studied

250 mg of leaf extract capsule twice a day for 8 weeks; 5 mL aqueous leaf twice a day for 12 weeks.

Who was studied

Overweight/obese young adults; adults with metabolic syndrome; India.

Limits

Weight changes were small and measured as BMI; diet and exercise not described; only 8 to 12 weeks.

Why researchers looked

The review's authors argue that tulsi's effects on sugar, fats and pressure together fit a lifestyle-disease picture, with inflammation as a common thread.

Traditional use

Daily tulsi is part of Ayurvedic lifestyle care; weight loss is not a classical claim.

Proposed mechanism Preliminary mechanism

The review proposes that tulsi's anti-inflammatory compounds may act on several pathways at once. This is a theory based mainly on lab and animal studies.

A proposed mechanism does not show that the effect happens in people.

No change in liver enzymes in the pilot; see the safety file.

^{76 25 45 37}

Immune markers

Low certainty

In one small crossover trial of 22 healthy adults, 300 mg of a tulsi leaf extract a day for 4 weeks raised some immune signals in blood tests (interferon-gamma, interleukin-4, T-helper cells and NK cells) compared with placebo. That shows the immune system was changed, not that people got sick less often, and no trial has counted colds or infections with tulsi alone.

4 studies300 mg of ethanolic leaf extract capsule once a day on an empty stoma…

Studies, doses and limits

What the trials found

Mondal 2011 (22 healthy volunteers in a double-blind crossover trial): after 4 weeks of tulsi, interferon-gamma (p=0.039), interleukin-4 (p=0.001), T-helper cells (p=0.001) and NK cells (p=0.017) were higher than with placebo. A separate five-herb tea study (Bhat 2010; ashwagandha, licorice, ginger, tulsi and cardamom) in people aged 55 and over with low NK activity found higher NK activity versus regular tea, but tulsi cannot be separated from the other herbs. The review also lists small 1980s open trials in viral hepatitis and viral encephalitis that cannot be treated as proof.

Results

Higher lab markers of immune activity; no study counted fewer infections.

Effect sizes as reported

p-values only; no effect sizes available.

Why this rating

One small trial of healthy people and a mixed-herb tea; lab markers only. Compiler's rating.

Form and dose studied

300 mg of ethanolic leaf extract capsule once a day on an empty stomach for 4 weeks.

Who was studied

Healthy adults in India.

Limits

A higher immune marker is not necessarily better protection; too much immune activity can be unhelpful in some conditions. No long-term data.

Why researchers looked

In India tulsi leaf eaten on an empty stomach is traditionally believed to raise resistance to illness, and lab studies showed it influences immune cells.

Traditional use

Daily tulsi leaves or tea are a long-standing household practice for coughs, colds and general resistance in India.

Proposed mechanism Preliminary mechanism

Laboratory work suggests tulsi extracts act on immune cells and cytokines. The human trial measured the signals but not how they work.

A proposed mechanism does not show that the effect happens in people.

People with autoimmune disease or on immune-suppressing drugs should ask their doctor first. See the safety file.

^{55 13 70 37}

Gum health and dental plaque (mouthwash, toothpaste, gel)

Low certainty

Dental trials from India tested tulsi mouthwash, toothpaste and gum gels. In most, tulsi lowered plaque and gum inflammation and was often about as good as chlorhexidine (the standard medicated rinse) after a month; in one trial tulsi toothpaste matched fluoride toothpaste and beat placebo toothpaste. The trials are small, short and mostly report p-values.

7 studiesMouthwash 4% extract or unspecified, 10 ml twice daily for 15 to 30 d…

Studies, doses and limits

What the trials found

Mouthwash: Penmetsa 2019 (60 adults with gingivitis, tulsi vs aloe vera vs chlorhexidine rinse twice daily, with scaling) found all three equally effective at 30 days for plaque, gum and bleeding scores. Kamran 2023 (75 people with braces) found that adding a 4% tulsi or noni mouthwash lowered plaque and lowered TNF-alpha, IL-1 alpha and IL-1 beta in gum fluid. Toothpaste: Nadar 2020 (84 schoolchildren, 4% tulsi toothpaste for 21 days) gave a bigger fall in plaque and gum scores than placebo toothpaste and the same as fluoride toothpaste. Gel in gum pockets after cleaning: Deepika 2021 (30 people, 2% gel for 1 month, compared with chlorhexidine gel; mixed results), Rahalkar 2021 (15 people) and Agrawal 2024 (tulsi about as good as curcumin) found small extra benefits mainly on a bacterial enzyme test. An oral submucous fibrosis paste trial (Biswas 2022, 60 people) reported less burning and better mouth opening but had no control group.

Results

Lower plaque, gum redness and bleeding scores, about equal to chlorhexidine at 30 days in the best-designed comparison.

Effect sizes as reported

Mostly p-values; no effect sizes or confidence intervals in the abstracts.

Why this rating

Many small randomised trials with consistent direction, but short (1 to 4 weeks), tiny groups, abstract-level reading, unclear extract strengths. Compiler's rating.

Form and dose studied

Mouthwash 4% extract or unspecified, 10 ml twice daily for 15 to 30 days; 4% tulsi toothpaste for 21 days; 2% gel for 1 month.

Who was studied

Schoolchildren and adults with gingivitis, gum pockets, or braces, India.

Limits

Not a replacement for brushing, flossing or dentist care. Strengths and extraction methods differ. No long-term follow-up.

Why researchers looked

Chewing tulsi leaves and oral rinses with tulsi are traditional in India, and tulsi contains eugenol and other compounds that kill bacteria in the lab.

Traditional use

Tulsi leaves are traditionally chewed or used in mouth care in India; the 2017 review cites ethnomedicine surveys of oral care.

Proposed mechanism Laboratory research

Tulsi extracts kill mouth bacteria in laboratory tests, and a mouthwash trial found lower inflammatory chemicals in gum fluid.

A proposed mechanism does not show that the effect happens in people.

Mouthwash and gel studies did not report problems in the abstracts, but they were not safety studies. Do not swallow mouthwash. See the safety file.

^{65 40 60 24 67 3 16}

Mouth bacteria, tooth decay germs and bad breath

Low certainty

Tulsi rinses lowered levels of Streptococcus mutans (a germ linked to cavities) in several short trials, and a 15-day trial found tulsi helped bad breath but less than chlorhexidine or hydrogen peroxide. These are lab counts over a week or two, not proof of fewer cavities.

5 studies4% tulsi leaf extract rinses (10 ml twice daily or per instructions);…

Studies, doses and limits

What the trials found

Agarwal 2011 (45 schoolchildren, 4% tulsi rinse versus chlorhexidine and Listerine, crossover): all three lowered S. mutans, with no significant difference between them. Megalaa 2018 (60 children and young people at high caries risk, 4% tulsi rinse versus sodium fluoride rinse for 7 days): S. mutans fell in all groups, tulsi lowered it more than the others at 1 hour; fluoride raised saliva pH more. Jain 2022 (80 dental students, 10 ml twice daily for 2 weeks): tulsi rinse lowered S. mutans and L. acidophilus and the hygiene score, like chlorhexidine. Sharma 2019 (45 adults with bad breath, 10 ml twice daily for 15 days): tulsi lowered bad breath, plaque and gum scores, but less than chlorhexidine or hydrogen peroxide. Nomura 2023 (44 patients having radioiodine treatment, 180 ml of basil tea from 2 g of holy basil leaves after each meal for 4 days versus water) found less rise in cavity-causing bacteria and other saliva changes, but the main aim was side effects of cancer treatment.

Results

Fewer cavity-causing bacteria and lower bad breath scores, usually similar to the standard rinse but not better.

Effect sizes as reported

Mostly p-values; no effect sizes in the abstracts.

Why this rating

Several randomised trials agree on direction, but they measure bacteria counts and breath scores over days to 2 weeks, have small groups, and none counted cavities. Compiler's rating.

Form and dose studied

4% tulsi leaf extract rinses (10 ml twice daily or per instructions); holy basil leaf tea 2 g per cup, after meals, for 4 days (one trial).

Who was studied

Schoolchildren, students, adults, India; Japanese patients having radioiodine treatment.

Limits

A lower bacteria count in saliva is not fewer cavities. Short and small. Not a substitute for fluoride toothpaste.

Why researchers looked

Cavity-causing bacteria are the targets of mouth rinses, and tulsi's eugenol-rich oil kills them in the lab.

Traditional use

Chewing tulsi leaves for oral health is a traditional practice in India.

Proposed mechanism Laboratory research

Antibacterial plant compounds such as eugenol act against mouth bacteria in lab tests.

A proposed mechanism does not show that the effect happens in people.

No harm was noted in the abstracts; none were safety studies. Rinses are not for swallowing.

^{1 54 36 80 63}

Fighting germs and infections

Not enough evidence

In the lab tulsi oils and extracts kill many bacteria and fungi, and mouth rinse trials show lower tooth-decay bacteria. For infections in the body there is almost no usable human evidence: only small, old open trials listed in a review, and cell-culture work on pneumonia bacteria. It should not be used to treat an infection.

3 studiesNot established.

Studies, doses and limits

What the trials found

In people, the only direct evidence is in the mouth (see the oral sections). Beyond that, the 2017 review table lists very small, old open trials: viral hepatitis (20 people, 10 g of fresh leaf aqueous extract, symptoms improved within 2 weeks) and viral encephalitis (14 people, compared with dexamethasone, higher survival with tulsi). These are not controlled or large enough to rely on. Cell-culture work (Suresh 2022) showed less lung cell death from Klebsiella with basil extract.

Results

Strong antibacterial effects in the lab; no reliable human evidence for infections outside the mouth.

Why this rating

No well-run human trial of tulsi against an infection outside the mouth; evidence is lab-based or from 1980s open trials. Compiler's rating.

Form and dose studied

Not established.

Limits

Do not use tulsi in place of antibiotics, antivirals or medical care.

Why researchers looked

Tulsi is known as a household remedy for coughs, colds and fevers, and its oil is rich in eugenol, an antibacterial compound.

Traditional use

Tulsi tea and leaf have been used in India for fevers, coughs and infections for centuries.

Proposed mechanism Laboratory research

Tulsi extract protected human lung cells from Klebsiella bacteria in a dish and raised interferon-gamma, but this has not been tested in people with pneumonia.

A proposed mechanism does not show that the effect happens in people.

Seek medical care for fever, breathing trouble or infection symptoms.

^{87 70 37}

Cough, asthma and COPD

Not enough evidence

Tulsi is a traditional cough and asthma remedy in India, but there is almost no modern human evidence. The only human study listed is a 1983 open trial of 20 people with asthma in a review, and the other findings are from rodents or cell dishes. We cannot say tulsi helps cough, asthma or COPD.

5 studiesNot established.

Studies, doses and limits

What the trials found

The 2017 review lists one small open trial (Sharma 1983, 20 adults with asthma, aqueous leaf tablets 500 mg three times daily for 1 week) with relief within 3 days and better vital capacity, and no control group. No randomised trial for cough, bronchitis or COPD was found in PubMed. Animal and lab work: Srivastava 2023 (rodents, cigarette-smoke COPD model) and Suresh 2022 (lung cells).

Results

Reported symptom relief in one uncontrolled 1983 trial; lung protection in animals.

Why this rating

No controlled human trial; only an old open trial and animal/cell work. Compiler's rating.

Form and dose studied

Not established.

Limits

Asthma and COPD can be serious; tulsi must not replace prescribed inhalers or medicines.

Why researchers looked

Tulsi tea and juice are a classic home remedy for coughs, colds and wheeze in India.

Traditional use

Used traditionally for cough, asthma and breathlessness; see the 2017 review's description of Ayurvedic uses.

Proposed mechanism Animal research

In smoke-exposed rodents, a leaf extract lowered lung inflammation and oxidant damage. A guinea-pig cough study exists but its results could not be read (title only).

A proposed mechanism does not show that the effect happens in people.

Do not stop prescribed asthma or COPD medicine. Seek urgent help for breathing trouble.

^{79 85 61 87 37}

Skin and acne

Not enough evidence

Tulsi is used in skin care and has anti-bacterial and anti-inflammatory activity in the lab, but I found no human trial of tulsi for acne or any skin condition in the databases searched.

1 studiesNot established.

Studies, doses and limits

What the trials found

No randomised or other human trial of tulsi for acne, eczema, psoriasis or wounds was found in PubMed or Europe PMC searches for this profile. A dental paste study for oral submucous fibrosis is about the mouth lining, not skin.

Results

No human results.

Why this rating

No human evidence found.

Form and dose studied

Not established.

Limits

A lab effect on bacteria in a dish does not predict a skin effect in people.

Why researchers looked

Tulsi extracts and oil act against skin bacteria in the lab, which is why they appear in skin products.

Traditional use

Tulsi leaf paste and juice have been applied to skin problems in Indian folk medicine.

Proposed mechanism Laboratory research

Lab work shows tulsi extracts act against skin and scalp microbes and reduce inflammation chemicals in cells.

A proposed mechanism does not show that the effect happens in people.

No human skin data; if you try a product on skin, test a small patch first.

³⁷

Fertility, sperm and PCOS

Not enough evidence

No human trial has tested tulsi for fertility, sperm quality or polycystic ovary syndrome. A few rat studies suggest tulsi protected testes from drug damage or eased PCOS-like changes. There is not enough to say anything about people.

1 studiesNot established for people.

Studies, doses and limits

What the trials found

No human trial found. Animal: Tuimah Alabedi 2021 (40 rats, 20 mg/kg a day for 1 week) showed some protection of sperm-making tissue from filgrastim damage.

Results

Protective effect in rats only.

Why this rating

Only animal data.

Form and dose studied

Not established for people.

Limits

Rat results often do not carry over to people.

Why researchers looked

Antioxidant plants are often tested for protection of reproductive tissue in animals.

Traditional use

Ayurvedic texts mention tulsi for women's health, but no precise fertility use is established.

Proposed mechanism Animal research

In rats, tulsi extract reduced tissue damage from the drug filgrastim and showed antioxidant action; this is animal work.

A proposed mechanism does not show that the effect happens in people.

No human safety data exist for fertility; anyone trying to conceive should ask a doctor before using concentrated extracts.

⁸⁸

Exercise performance and physical fatigue

Not enough evidence

One small trial reported in a review (30 healthy young adults, a snack bar with tulsi extract for 2 weeks) found better physical performance and less fatigue than a control bar. I could not read the original, so it is a hint only. Stress-related fatigue is covered on the mind page.

2 studiesSnack bar with 0.5% ethanolic leaf extract, twice a day (per the revi…

Studies, doses and limits

What the trials found

Venu Prasad 2014, as summarised in the 2017 review table (30 healthy adults aged 18 to 30, bar containing 0.5% tulsi ethanolic leaf extract, one bar twice a day for 2 weeks versus a control bar): physical performance improved, fatigue and creatine kinase (a muscle-stress marker) were lower and the rise in lactic acid was smaller. I could not locate the paper in PubMed and have no numbers.

Results

Better performance and lower fatigue/muscle-stress markers in one small trial.

Effect sizes as reported

Not available.

Why this rating

One small trial of 2 weeks, summary only, unread original.

Form and dose studied

Snack bar with 0.5% ethanolic leaf extract, twice a day (per the review).

Who was studied

Healthy young adults, India.

Limits

One trial, two weeks, a snack bar mix.

Why researchers looked

Tulsi is called an adaptogen, and adaptogens are often tested for stamina and tiredness.

Traditional use

Tulsi is traditionally taken for vigor and resistance to stress; not as a sports aid.

Proposed mechanism Pharmacological theory

No mechanism for exercise is established; adaptogen effects are a theory.

A proposed mechanism does not show that the effect happens in people.

None reported in the review table.

^{92 37}

Inflammation and uric acid

Not enough evidence

The authors of the 2017 review suggest tulsi's many effects may share inflammation as a root, and tulsi lowers inflammation markers in lab and animal work. In people, evidence is thin: one 200-person trial in gout (a tincture) reported lower uric acid, and tulsi mouthwash lowered some inflammation markers in gum fluid. No trial measured CRP or joint pain in arthritis.

4 studiesTulsi tincture 10 drops three times a day (gout trial); 4% mouthwash …

Studies, doses and limits

What the trials found

Ahmad 2013, as listed in the review table (200 adults with gouty arthritis, a commercial tulsi tincture 10 drops three times a day for 12 weeks versus a wild rosemary tincture): serum uric acid fell significantly. Rai 1997 (27 adults) also reported lower uric acid. Kamran 2023: braces patients using a 4% tulsi mouthwash had lower TNF-alpha, IL-1 alpha and IL-1 beta in gum fluid. No trial of tulsi measuring CRP or arthritis symptoms was found.

Results

Lower uric acid in a gout trial and lower gum-fluid inflammation markers in a mouthwash trial.

Effect sizes as reported

No numbers available.

Why this rating

The key gout trial is known only from a review table, compared with another herb rather than placebo; the gum-fluid result is local to the mouth.

Form and dose studied

Tulsi tincture 10 drops three times a day (gout trial); 4% mouthwash (braces trial).

Who was studied

Adults with gout, adults with braces

Limits

Uric acid is a lab value, not gout attacks avoided.

Why researchers looked

Chronic inflammation underlies many lifestyle diseases, and tulsi is anti-inflammatory in the lab.

Traditional use

Tulsi is used in Ayurveda for inflammatory and painful conditions.

Proposed mechanism Preliminary mechanism

Tulsi extracts lower inflammatory chemicals in cells and animals (for example NF-kB, TNF-alpha); the review suggests multiple compounds may act together.

A proposed mechanism does not show that the effect happens in people.

Gout needs medical treatment; do not replace prescribed medicine.

^{5 68 40 37}

Thyroid

Not enough evidence

No human trial tested tulsi for an underactive or overactive thyroid. The only thyroid-related trial gave holy basil tea to people having radioactive iodine treatment after thyroid cancer surgery and looked at anxiety and mouth and salivary-gland side effects, not thyroid function.

1 studiesNot established.

Studies, doses and limits

What the trials found

Nomura 2023 (44 people after thyroid cancer surgery getting radioiodine treatment): holy basil tea (2 g of leaves per 180 ml after each meal for 4 days) versus distilled water lowered anxiety scores and some saliva changes, and the salivary gland scan suggested better washout. This was about treatment side effects. No trial measured TSH, T3 or T4 with tulsi.

Results

No thyroid function data.

Why this rating

No human thyroid-function studies.

Form and dose studied

Not established.

Who was studied

One trial: 44 thyroid cancer patients in Japan.

Limits

Not a trial of thyroid disease treatment.

Why researchers looked

Tulsi is sometimes listed among adaptogens for endocrine balance, with little evidence behind that claim.

Traditional use

No classical thyroid indication is established for tulsi.

Proposed mechanism Pharmacological theory

None demonstrated for thyroid hormones in people.

A proposed mechanism does not show that the effect happens in people.

If you have a thyroid condition or take thyroid medicine, ask your doctor before adding herbs.

⁶³

Connections to the rest of health

How Holy Basil (Tulsi) connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.

Explore every connection: goals, body systems, organs, symptoms, genes

Kind of connection Connected to Search

A. Wellness goals

Connected to	Kind of connection	Evidence status	Context	Studies
Stress Reduction	Potential benefit	Low certainty	Stress: Holy basil extracts have been tested for stress in a few small to medium trials. Two placebo-controlled trials of branded extracts (OciBest and Holixer) found lower stress scores, and the newer one also found lower hair cortisol. Both were funded or linked to the extract makers, and there are few independent trials, so confidence is low.	^{77 50 72 53 37 51 32}
Resilience Support	Potential benefit	Low certainty	Stress: Holy basil extracts have been tested for stress in a few small to medium trials. Two placebo-controlled trials of branded extracts (OciBest and Holixer) found lower stress scores, and the newer one also found lower hair cortisol. Both were funded or linked to the extract makers, and there are few independent trials, so confidence is low.	^{77 50 72 53 37 51 32}
Anxiety Support	Potential benefit	Very low certainty	Anxiety and generalized anxiety disorder: One small uncontrolled hospital study in 35 people with generalized anxiety disorder found lower anxiety after 60 days of a leaf extract, but with no comparison group it cannot show the herb did it. Placebo-controlled stress trials add only indirect hints. There is no good trial of holy basil for diagnosed anxiety.	^{14 72 53 21}
Calm Relaxation	Potential benefit	Very low certainty	Anxiety and generalized anxiety disorder: One small uncontrolled hospital study in 35 people with generalized anxiety disorder found lower anxiety after 60 days of a leaf extract, but with no comparison group it cannot show the herb did it. Placebo-controlled stress trials add only indirect hints. There is no good trial of holy basil for diagnosed anxiety.	^{14 72 53 21}
Mood Balance	Preliminary mechanism	Very low certainty	Mood and depression: There is no good human trial of holy basil for depression. Mood was measured in trials of holy basil for stress, but the abstracts give little detail. Evidence is very thin and mostly from animals.	^{14 50 53 32 21}
Memory Support	Potential benefit	Very low certainty	Thinking, attention and memory: One small placebo-controlled study in healthy adults found faster reaction times and fewer errors on attention and memory tests after 30 days of a holy basil leaf extract. It has not been repeated, the abstract gives no group size, and the evidence is very limited. Animal studies show brain-protective effects, which are not proof for people.	^{72 77 94 90}
Cognitive Performance	Potential benefit	Very low certainty	Thinking, attention and memory: One small placebo-controlled study in healthy adults found faster reaction times and fewer errors on attention and memory tests after 30 days of a holy basil leaf extract. It has not been repeated, the abstract gives no group size, and the evidence is very limited. Animal studies show brain-protective effects, which are not proof for people.	^{72 77 94 90}
Better Focus	Potential benefit	Very low certainty	Thinking, attention and memory: One small placebo-controlled study in healthy adults found faster reaction times and fewer errors on attention and memory tests after 30 days of a holy basil leaf extract. It has not been repeated, the abstract gives no group size, and the evidence is very limited. Animal studies show brain-protective effects, which are not proof for people.	^{72 77 94 90}
Mental Clarity	Potential benefit	Very low certainty	Thinking, attention and memory: One small placebo-controlled study in healthy adults found faster reaction times and fewer errors on attention and memory tests after 30 days of a holy basil leaf extract. It has not been repeated, the abstract gives no group size, and the evidence is very limited. Animal studies show brain-protective effects, which are not proof for people.	^{72 77 94 90}
Better Sleep	Potential benefit	Low certainty	Sleep: Holy basil extracts were linked to better self-rated sleep in two stress trials. The 2022 trial found a better insomnia score than placebo, but the Fitbit results are not reported in the abstract, and the authors say the sleep findings need confirming with objective measures. Evidence is low.	^{50 77 53}
Sleep Quality	Potential benefit	Low certainty	Sleep: Holy basil extracts were linked to better self-rated sleep in two stress trials. The 2022 trial found a better insomnia score than placebo, but the Fitbit results are not reported in the abstract, and the authors say the sleep findings need confirming with objective measures. Evidence is low.	^{50 77 53}
Reduce Fatigue	Potential benefit	Very low certainty	Fatigue and burnout: The only direct finding is that people with stress symptoms taking OciBest reported less frequent exhaustion than on placebo. No trial was designed to test holy basil for fatigue or burnout, so evidence is very limited. Exercise performance and physical fatigue: One small trial reported in a review (30 healthy young adults, a snack bar with tulsi extract for 2 weeks) found better physical performance and less fatigue than a control bar. I could not read the original, so it is a hint only. Stress-related fatigue is covered on the mind page.	^{77 53 32 92 37}
Burnout Recovery	Potential benefit	Very low certainty	Fatigue and burnout: The only direct finding is that people with stress symptoms taking OciBest reported less frequent exhaustion than on placebo. No trial was designed to test holy basil for fatigue or burnout, so evidence is very limited.	^{77 53 32}
Energy Boost	Potential benefit	Very low certainty	Fatigue and burnout: The only direct finding is that people with stress symptoms taking OciBest reported less frequent exhaustion than on placebo. No trial was designed to test holy basil for fatigue or burnout, so evidence is very limited.	^{77 53 32}
Blood Sugar Balance	Potential benefit	Low certainty	Blood sugar and type 2 diabetes: Several small human trials, mostly from India and many decades old, found lower fasting and after-meal blood sugar when people with type 2 diabetes took holy basil (tulsi) leaf powder or extract. The best-described trial found fasting blood sugar about 21 mg/dl lower than on placebo. The 2017 review that gathered the human studies rated only a minority as good quality, so this is promising but low-certainty. It is not a replacement for diabetes medicine. Metabolic syndrome and body weight: Metabolic syndrome is a cluster of high blood sugar, blood pressure, blood fats and waist size. Tulsi has been tried in only a few small trials. One pilot in 30 overweight young adults found a lower BMI, insulin and insulin resistance in the tulsi group after 8 weeks, but there was no placebo. A larger 100-person trial in metabolic syndrome is listed in a review but I could not read it.	^{37 2 84 28 91 68 26 76 25 45}
Metabolic Health	Potential benefit	Low certainty	Blood sugar and type 2 diabetes: Several small human trials, mostly from India and many decades old, found lower fasting and after-meal blood sugar when people with type 2 diabetes took holy basil (tulsi) leaf powder or extract. The best-described trial found fasting blood sugar about 21 mg/dl lower than on placebo. The 2017 review that gathered the human studies rated only a minority as good quality, so this is promising but low-certainty. It is not a replacement for diabetes medicine. Cholesterol and blood fats: A handful of small trials report better blood fats (triglycerides, LDL, HDL) with tulsi. The one trial I could read (30 overweight young adults, 250 mg of leaf extract twice a day for 8 weeks) found better triglycerides, LDL and HDL than at the start, but only HDL was clearly better than the untreated group. Evidence is low-certainty.	^{37 2 84 28 91 68 26 76 25 56 45}
Cholesterol Balance	Potential benefit	Low certainty	Cholesterol and blood fats: A handful of small trials report better blood fats (triglycerides, LDL, HDL) with tulsi. The one trial I could read (30 overweight young adults, 250 mg of leaf extract twice a day for 8 weeks) found better triglycerides, LDL and HDL than at the start, but only HDL was clearly better than the untreated group. Evidence is low-certainty.	^{76 2 37 25 26 68 56}
Heart Health	Potential benefit	Low certainty	Cholesterol and blood fats: A handful of small trials report better blood fats (triglycerides, LDL, HDL) with tulsi. The one trial I could read (30 overweight young adults, 250 mg of leaf extract twice a day for 8 weeks) found better triglycerides, LDL and HDL than at the start, but only HDL was clearly better than the untreated group. Evidence is low-certainty. Blood pressure: A few very small, old trials of fresh tulsi juice or leaf powder reported lower blood pressure in people with high blood pressure or metabolic syndrome. The details could not be checked, and one trial was in women with low blood pressure. There is not enough reliable evidence to say tulsi lowers blood pressure.	^{76 2 37 25 26 68 56 75 45 12}
Blood Pressure Support	Potential benefit	Very low certainty	Blood pressure: A few very small, old trials of fresh tulsi juice or leaf powder reported lower blood pressure in people with high blood pressure or metabolic syndrome. The details could not be checked, and one trial was in women with low blood pressure. There is not enough reliable evidence to say tulsi lowers blood pressure.	^{37 75 25 45 12}
Weight Management	Potential benefit	Very low certainty	Metabolic syndrome and body weight: Metabolic syndrome is a cluster of high blood sugar, blood pressure, blood fats and waist size. Tulsi has been tried in only a few small trials. One pilot in 30 overweight young adults found a lower BMI, insulin and insulin resistance in the tulsi group after 8 weeks, but there was no placebo. A larger 100-person trial in metabolic syndrome is listed in a review but I could not read it.	^{76 25 45 37}
Immune Support	Biological association	Low certainty	Immune markers: In one small crossover trial of 22 healthy adults, 300 mg of a tulsi leaf extract a day for 4 weeks raised some immune signals in blood tests (interferon-gamma, interleukin-4, T-helper cells and NK cells) compared with placebo. That shows the immune system was changed, not that people got sick less often, and no trial has counted colds or infections with tulsi alone.	^{55 13 70 37}
Digestive Support	Demonstrated clinical effect	Low certainty	Gum health and dental plaque (mouthwash, toothpaste, gel): Dental trials from India tested tulsi mouthwash, toothpaste and gum gels. In most, tulsi lowered plaque and gum inflammation and was often about as good as chlorhexidine (the standard medicated rinse) after a month; in one trial tulsi toothpaste matched fluoride toothpaste and beat placebo toothpaste. The trials are small, short and mostly report p-values. Mouth bacteria, tooth decay germs and bad breath: Tulsi rinses lowered levels of Streptococcus mutans (a germ linked to cavities) in several short trials, and a 15-day trial found tulsi helped bad breath but less than chlorhexidine or hydrogen peroxide. These are lab counts over a week or two, not proof of fewer cavities.	^{65 40 60 24 67 3 16 1 54 36 80 63}
Immune Support	Preliminary mechanism	Not enough evidence	Fighting germs and infections: In the lab tulsi oils and extracts kill many bacteria and fungi, and mouth rinse trials show lower tooth-decay bacteria. For infections in the body there is almost no usable human evidence: only small, old open trials listed in a review, and cell-culture work on pneumonia bacteria. It should not be used to treat an infection.	^{87 70 37}
Immune Support	Traditional use	Not enough evidence	Cough, asthma and COPD: Tulsi is a traditional cough and asthma remedy in India, but there is almost no modern human evidence. The only human study listed is a 1983 open trial of 20 people with asthma in a review, and the other findings are from rodents or cell dishes. We cannot say tulsi helps cough, asthma or COPD.	^{79 85 61 87 37}
Healthy Skin	Preliminary mechanism	Not enough evidence	Skin and acne: Tulsi is used in skin care and has anti-bacterial and anti-inflammatory activity in the lab, but I found no human trial of tulsi for acne or any skin condition in the databases searched.	³⁷
Fertility Support	Preliminary mechanism	Not enough evidence	Fertility, sperm and PCOS: No human trial has tested tulsi for fertility, sperm quality or polycystic ovary syndrome. A few rat studies suggest tulsi protected testes from drug damage or eased PCOS-like changes. There is not enough to say anything about people.	⁸⁸
Mens Vitality	Preliminary mechanism	Not enough evidence	Fertility, sperm and PCOS: No human trial has tested tulsi for fertility, sperm quality or polycystic ovary syndrome. A few rat studies suggest tulsi protected testes from drug damage or eased PCOS-like changes. There is not enough to say anything about people.	⁸⁸
Womens Wellness	Preliminary mechanism	Not enough evidence	Fertility, sperm and PCOS: No human trial has tested tulsi for fertility, sperm quality or polycystic ovary syndrome. A few rat studies suggest tulsi protected testes from drug damage or eased PCOS-like changes. There is not enough to say anything about people.	⁸⁸
Physical Stamina	Potential benefit	Not enough evidence	Exercise performance and physical fatigue: One small trial reported in a review (30 healthy young adults, a snack bar with tulsi extract for 2 weeks) found better physical performance and less fatigue than a control bar. I could not read the original, so it is a hint only. Stress-related fatigue is covered on the mind page.	^{92 37}
Endurance Support	Potential benefit	Not enough evidence	Exercise performance and physical fatigue: One small trial reported in a review (30 healthy young adults, a snack bar with tulsi extract for 2 weeks) found better physical performance and less fatigue than a control bar. I could not read the original, so it is a hint only. Stress-related fatigue is covered on the mind page.	^{92 37}
Inflammation Balance	Preliminary mechanism	Not enough evidence	Inflammation and uric acid: The authors of the 2017 review suggest tulsi's many effects may share inflammation as a root, and tulsi lowers inflammation markers in lab and animal work. In people, evidence is thin: one 200-person trial in gout (a tincture) reported lower uric acid, and tulsi mouthwash lowered some inflammation markers in gum fluid. No trial measured CRP or joint pain in arthritis.	^{5 68 40 37}
Joint Support	Preliminary mechanism	Not enough evidence	Inflammation and uric acid: The authors of the 2017 review suggest tulsi's many effects may share inflammation as a root, and tulsi lowers inflammation markers in lab and animal work. In people, evidence is thin: one 200-person trial in gout (a tincture) reported lower uric acid, and tulsi mouthwash lowered some inflammation markers in gum fluid. No trial measured CRP or joint pain in arthritis.	^{5 68 40 37}
Thyroid Support	Biological association	Not enough evidence	Thyroid: No human trial tested tulsi for an underactive or overactive thyroid. The only thyroid-related trial gave holy basil tea to people having radioactive iodine treatment after thyroid cancer surgery and looked at anxiety and mouth and salivary-gland side effects, not thyroid function.	⁶³

B. Body systems

Connected to	Kind of connection	Evidence status	Context	Studies
Reproductive system	Contraindication	Very low certainty	Avoid in pregnancy and while trying to conceive; precaution based on animal data. Preparation or compound: Leaf extracts	^{66 93 41}
Digestive system	Adverse effect or risk	Low certainty	Mild nausea and digestive upset occasionally reported, similar to placebo. Preparation or compound: Leaf extracts	^{50 37}
Endocrine system	Adverse effect or risk	Very low certainty	Hormone changes (T4, estradiol, progesterone, testosterone, FSH, LH) in animals only. Preparation or compound: Leaf extracts	^{64 66 78}
Cardiovascular system	Drug or supplement interaction	Very low certainty	Lowered blood pressure in dogs; interactions with blood pressure medicines are theoretical. Preparation or compound: Fixed oil	⁸²
Stress Mood	Biological association	Low certainty	Studied for: Stress Studied for: Anxiety and generalized anxiety disorder	^{77 50 72 53 37 51 32 14 21}
Nervous System	Biological association	Low certainty	Studied for: Stress Studied for: Anxiety and generalized anxiety disorder	^{77 50 72 53 37 51 32 14 21 94 90}
Sleep Recovery	Biological association	Low certainty	Studied for: Sleep	^{50 77 53}
Endocrine System	Biological association	Low certainty	Studied for: Blood sugar and type 2 diabetes Studied for: Metabolic syndrome and body weight	^{37 2 84 28 91 68 26 76 25 45 63}
Metabolism Weight	Biological association	Low certainty	Studied for: Blood sugar and type 2 diabetes Studied for: Cholesterol and blood fats	^{37 2 84 28 91 68 26 76 25 56 45}
Cardiovascular System	Biological association	Low certainty	Studied for: Cholesterol and blood fats Studied for: Blood pressure	^{76 2 37 25 26 68 56 75 45 12}
Immune System	Biological association	Low certainty	Studied for: Immune markers Studied for: Fighting germs and infections	^{55 13 70 37 87 5 68 40}
Digestive System	Biological association	Low certainty	Studied for: Gum health and dental plaque (mouthwash, toothpaste, gel) Studied for: Mouth bacteria, tooth decay germs and bad breath	^{65 40 60 24 67 3 16 1 54 36 80 63}
Respiratory System	Biological association	Not enough evidence	Studied for: Fighting germs and infections Studied for: Cough, asthma and COPD	^{87 70 37 79 85 61}
Integumentary System	Biological association	Not enough evidence	Studied for: Skin and acne	³⁷
Reproductive System	Biological association	Not enough evidence	Studied for: Fertility, sperm and PCOS	⁸⁸
Musculoskeletal System	Biological association	Not enough evidence	Studied for: Exercise performance and physical fatigue Studied for: Inflammation and uric acid	^{92 37 5 68 40}

C. Body parts and organs

Connected to	Kind of connection	Evidence status	Context	Studies
Reproductive organs	Adverse effect or risk	Very low certainty	Lower sperm count and changed sex hormones in rats and rabbits; reduced ovulation reported in rats. No human data. A safety relationship, not a benefit. Preparation or compound: Leaf extracts and eugenol (animal)	^{6 78 66}
Thyroid	Adverse effect or risk	Very low certainty	Lower T4 in mice; no human data. Preparation or compound: Leaf extract (mouse)	⁶⁴
Blood vessels	Drug or supplement interaction	Very low certainty	Possible slower blood clotting; test-tube and animal data only. Preparation or compound: Fixed oil, leaf extract, eugenol	^{82 52 35}
Liver	Adverse effect or risk	Not enough evidence	No case reports found; liver enzymes unchanged in a small trial; not a benefit claim. Preparation or compound: Leaf extracts	^{76 62}

D. Symptoms

Connected to	Kind of connection	Evidence status	Context	Studies
Stress	Potential benefit	Low certainty	Both main extract trials were positive on stress scores. The 2022 trial adds objective stress-hormone measures. Preparation or compound: Leaf and leaf extracts of holy basil	^{77 50 72 53 37 51 32}
Anxiety	Potential benefit	Very low certainty	One uncontrolled study improved; one placebo-controlled study improved over time but not versus placebo; one formula trial improved but is not specific to holy basil. Preparation or compound: Leaf and leaf extracts of holy basil	^{14 72 53 21}
Mood and depression	Preliminary mechanism	Very low certainty	Mood effects were small side findings in uncontrolled or multi-herb studies. Preparation or compound: Leaf and leaf extracts of holy basil	^{14 50 53 32 21}
Thinking, attention and memory	Potential benefit	Very low certainty	Faster reaction times and fewer errors in healthy adults on one small trial; self-rated forgetfulness improved in a stress trial. Preparation or compound: Leaf and leaf extracts of holy basil	^{72 77 94 90}
Sleep	Potential benefit	Low certainty	Better self-rated sleep in two single-extract trials; objective sleep not reported in the abstract. Preparation or compound: Leaf and leaf extracts of holy basil	^{50 77 53}
Fatigue and burnout	Potential benefit	Very low certainty	One item of a stress symptom scale improved. Preparation or compound: Leaf and leaf extracts of holy basil	^{77 53 32}
Blood sugar	Potential benefit	Low certainty	Lower fasting and after-meal blood sugar in every trial reported, with HbA1c lower in the trials that measured it (per the review table). Preparation or compound: Leaf and leaf extracts of holy basil	^{37 2 84 28 91 68 26}
Cholesterol and blood fats	Potential benefit	Low certainty	Mostly better triglycerides, LDL and HDL in small, short studies; total cholesterol change was mild or absent. Preparation or compound: Leaf and leaf extracts of holy basil	^{76 2 37 25 26 68 56}
Blood pressure	Potential benefit	Very low certainty	Lower blood pressure reported in the high-blood-pressure and metabolic syndrome trials, with no usable numbers. Preparation or compound: Leaf and leaf extracts of holy basil	^{37 75 25 45 12}
Metabolic syndrome and weight	Potential benefit	Very low certainty	Small improvements in BMI, insulin and insulin resistance in one open-label pilot; improvements reported in two further trials that could not be read. Preparation or compound: Leaf and leaf extracts of holy basil	^{76 25 45 37}
Immune markers	Biological association	Low certainty	Higher lab markers of immune activity; no study counted fewer infections. Preparation or compound: Leaf and leaf extracts of holy basil	^{55 13 70 37}
Gum health and plaque	Demonstrated clinical effect	Low certainty	Lower plaque, gum redness and bleeding scores, about equal to chlorhexidine at 30 days in the best-designed comparison. Preparation or compound: Leaf and leaf extracts of holy basil	^{65 40 60 24 67 3 16}
Mouth bacteria and bad breath	Demonstrated clinical effect	Low certainty	Fewer cavity-causing bacteria and lower bad breath scores, usually similar to the standard rinse but not better. Preparation or compound: Leaf and leaf extracts of holy basil	^{1 54 36 80 63}
Infections	Preliminary mechanism	Not enough evidence	Strong antibacterial effects in the lab; no reliable human evidence for infections outside the mouth. Preparation or compound: Leaf and leaf extracts of holy basil	^{87 70 37}
Cough, asthma and COPD	Traditional use	Not enough evidence	Reported symptom relief in one uncontrolled 1983 trial; lung protection in animals. Preparation or compound: Leaf and leaf extracts of holy basil	^{79 85 61 87 37}
Skin and acne	Preliminary mechanism	Not enough evidence	No human results. Preparation or compound: Leaf and leaf extracts of holy basil	³⁷
Fertility, sperm and PCOS	Preliminary mechanism	Not enough evidence	Protective effect in rats only. Preparation or compound: Leaf and leaf extracts of holy basil	⁸⁸
Exercise performance	Potential benefit	Not enough evidence	Better performance and lower fatigue/muscle-stress markers in one small trial. Preparation or compound: Leaf and leaf extracts of holy basil	^{92 37}
Inflammation and uric acid	Preliminary mechanism	Not enough evidence	Lower uric acid in a gout trial and lower gum-fluid inflammation markers in a mouthwash trial. Preparation or compound: Leaf and leaf extracts of holy basil	^{5 68 40 37}
Thyroid	Biological association	Not enough evidence	No thyroid function data. Preparation or compound: Leaf and leaf extracts of holy basil	⁶³

I. Biomarkers

Connected to	Kind of connection	Evidence status	Context	Studies
Blood glucose	Drug or supplement interaction	Low certainty	Lowers blood glucose in type 2 diabetes; relevant to hypoglycemia with diabetes drugs. Preparation or compound: Leaf and leaf extract	^{2 37}
Testosterone	Biological association	Very low certainty	Testosterone rose while sperm count fell in rabbits; human significance unknown. Preparation or compound: Fresh leaves (rabbits)	⁷⁸
Cortisol	Biological association	Low certainty	Measured in trials: mixed. A lab change is not the same as a health benefit.	^{50 72 51}
Perceived Stress Scale (PSS)	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{50 53}
Stress symptom rating scale	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	⁷⁷
Anxiety rating scales	Biological association	Very low certainty	Measured in trials: mixed. A lab change is not the same as a health benefit.	^{14 72}
Athens Insomnia Scale (AIS)	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	⁵⁰
Attention and memory test speed (Sternberg, Stroop) and P300 latency	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	⁷²
Fasting blood glucose	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{2 28 84 37}
After-meal (postprandial) blood glucose	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{2 91 37}
HbA1c (long-term blood sugar)	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{84 68}
Triglycerides	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	⁷⁶
LDL cholesterol	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	⁷⁶
HDL cholesterol	Biological association	Low certainty	Measured in trials: raised. A lab change is not the same as a health benefit.	⁷⁶
Total cholesterol	Biological association	Very low certainty	Measured in trials: mixed. A lab change is not the same as a health benefit.	^{2 37}
Insulin and insulin resistance	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	⁷⁶
Blood pressure	Biological association	Very low certainty	Measured in trials: mixed. A lab change is not the same as a health benefit.	^{75 25 12}
Interferon-gamma	Biological association	Low certainty	Measured in trials: raised. A lab change is not the same as a health benefit.	⁵⁵
Interleukin-4	Biological association	Low certainty	Measured in trials: raised. A lab change is not the same as a health benefit.	⁵⁵
Natural killer (NK) cells	Biological association	Low certainty	Measured in trials: raised. A lab change is not the same as a health benefit.	^{55 13}
Dental plaque index	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{65 60 80 40}
Gum (gingival) inflammation index	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{65 24 60}
Salivary Streptococcus mutans	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{1 54 36}
Serum uric acid	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	⁵
Liver enzymes (SGPT/ALT and SGOT/AST)	Biological association	Low certainty	Measured in trials: no-change. A lab change is not the same as a health benefit.	⁷⁶

J. Genes, receptors and enzymes

Connected to	Kind of connection	Evidence status	Context	Studies
CRHR1 (corticotropin-releasing hormone receptor 1)	Preliminary mechanism	In vitro	An O. sanctum extract and ursolic acid showed CRHR1 antagonist activity in a cell assay.	³⁸
HSD11B1 (11-beta-hydroxysteroid dehydrogenase type 1)	Preliminary mechanism	In vitro	Extract and ursolic acid inhibited this cortisol-activating enzyme in a cell-free test; not tested in people.	³⁸
COMT (catechol-O-methyltransferase)	Preliminary mechanism	In vitro	Inhibited by O. sanctum extract and constituents in a cell-free assay.	³⁸
PTGS1 / PTGS2 (COX-1 and COX-2)	Preliminary mechanism	In vitro	Eugenol, rosmarinic acid, apigenin and other isolated leaf compounds blocked both in test tubes.	⁴²
ALOX5 (5-lipoxygenase)	Preliminary mechanism	Animal	Seed oil lowered leukotriene- and arachidonic-acid-driven swelling in rats; the review calls this dual COX/LOX inhibition. Seed oil only, no leaf data read.	^{81 83}
IFNG and IL4 (interferon-gamma, interleukin-4)	Preliminary mechanism	Rct	Both rose after 4 weeks of ethanolic leaf extract compared with placebo in 22 healthy volunteers.	⁵⁵
CNR2 (CB2 cannabinoid receptor)	Preliminary mechanism	Animal	Bound and activated by purified (E)-caryophyllene, a major compound of tulsi oil; tulsi itself was not tested for CB2 activity.	^{30 31}
CYP2C9, CYP2D6, CYP3A4, CYP1A2	Preliminary mechanism	In vitro	Reduced by purified eugenol in human liver microsomes; relevant to possible herb-drug interactions, not tested with tulsi in people.	⁷
EOMT (eugenol O-methyltransferase)	Preliminary mechanism	In vitro	Plant enzyme that converts eugenol to methyleugenol; chemotypes differ in its activity and in methyleugenol amount.	⁷¹

K. Biological pathways

Connected to	Kind of connection	Evidence status	Context	Studies
HPA axis (hypothalamic-pituitary-adrenal stress axis)	Preliminary mechanism	Rct	Hair and stress-test cortisol were lower on a standardized extract than on placebo in one 100-person trial; a systematic review of HPA-axis trials found human effects of most herbs unclear.	^{50 51 38}
Brain monoamine and antioxidant systems (noradrenaline, dopamine, serotonin, glutathione, SOD, catalase)	Preliminary mechanism	Animal	Stress-induced changes in rat brain were reversed by ocimumosides A and B.	⁴

L. Active compounds

Connected to	Kind of connection	Evidence status	Context	Studies
Eugenol	Biological association	In vitro	Main smell compound. In a test tube it blocked the COX-1 and COX-2 enzymes (97% COX-1 block at 1000 micromolar) and acted as an antioxidant at 10 micromolar (p10782484). In human liver-cell preparations it reduced the activity of drug-processing enzymes CYP2C9, CYP2D6 and CYP3A4 (p38841106). Rat work shows a long half-life after a single dose (p17321520). Preparation or compound: Leaf (and the essential oil)	^{8 31 42 7 33 71}
Ursolic acid	Biological association	In vitro	In cell and test-tube assays, an O. sanctum extract and ursolic acid lowered cortisol release, blocked the CRH receptor CRHR1 and blocked the enzymes 11-beta-HSD1 and COMT (p26899341). That is lab data; the same group's rat trial used the whole extract, not ursolic acid alone. Preparation or compound: Leaf	^{8 38}
Oleanolic acid	Biological association	In vitro	Named as a main triterpene of O. tenuiflorum in a 2024 review (p39473808). No activity data for tulsi-specific oleanolic acid were read for this file. Preparation or compound: Leaf	^{8 15}
Rosmarinic acid	Biological association	In vitro	Antioxidant at 10 micromolar and a weak-to-moderate COX-1/COX-2 blocker in test tubes (58% COX-1 at 1000 micromolar) (p10782484). Human absorption data come from a perilla extract, not from tulsi (see pharmacokinetics). Preparation or compound: Leaf	^{42 15 9}
Apigenin and its glycosides (apigenin-7-O-glucuronide, apigenin-7-O-glucoside)	Biological association	In vitro	Free apigenin blocked COX-1 (65% at 1000 micromolar) and COX-2 in test tubes (p10782484). In rats, the apigenin glucuronide compound did not lower stress-raised corticosterone (p17850106). Preparation or compound: Leaf	^{42 34}
Luteolin and its glycosides	Biological association	In vitro	Luteolin glucosides were isolated from leaf extract (p17850106). No tulsi-specific activity result was read for luteolin itself. Preparation or compound: Leaf	^{8 34 15}
Carvacrol	Biological association	In vitro	No tulsi-based activity result read. Listed because it is often quoted for 'basil' in general; do not credit tulsi with it without a tulsi-specific measurement. Preparation or compound: Essential oil (reported mainly for the related species O. gratissimum)	^{89 31}
Beta-caryophyllene ((E)-caryophyllene)	Biological association	Animal	Outside tulsi, it bound the CB2 cannabinoid receptor (Ki 155 nM), was a CB2 agonist and cut inflammation in mice that have the receptor (not in mice lacking it) (p18574142). Whether the small amount in tulsi tea or capsules reaches such levels in people is not known. Preparation or compound: Essential oil	^{31 57 30}
Methyleugenol	Biological association	In vitro	Included because purple tulsi supply is dominated by a high methyl-eugenol type that the 2024 authors call 'moderately toxic and potentially carcinogenic' (p38520476). That safety statement is the authors' claim read in an abstract; safety detail belongs in the safety file. Preparation or compound: Leaf and essential oil; higher in some chemotypes, reported higher in purple tulsi	^{71 10 20}
Ocimumosides A and B (and ocimarin)	Biological association	Animal	In rats, ocimumosides A and B (40 mg/kg by mouth) lowered stress-raised corticosterone and sugar and shifted brain chemical levels back toward normal; ocimarin did not (p17850106, p22455995). Animal data only; no human work. PubChem name search found no record for 'ocimumoside', so no CID is given. Preparation or compound: Leaf	^{34 4}

Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 25, 2026).

Evidence at a glance: what changed in 23 lab markers

Tap a number to show only those markers. Counts are markers, not people.

Hormonal1 Metabolic511 Organ function1 Other932

The evidence

The research centre for Holy Basil (Tulsi). Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.

Evidence by outcome

Stress 7 studies · 436 people in trials Low certainty Anxiety and generalized anxiety disorder 4 studies · 186 people in trials Very low certainty Mood and depression 5 studies · 286 people in trials Very low certainty Thinking, attention and memory 4 studies · 278 people in trials Very low certainty Sleep 3 studies · 436 people in trials Low certainty Fatigue and burnout 3 studies · 336 people in trials Very low certainty Blood sugar and type 2 diabetes 7 studies · 180 people in trials Low certainty Cholesterol and blood fats 7 studies · 232 people in trials Low certainty Blood pressure 5 studies · 226 people in trials Very low certainty Metabolic syndrome and body weight 4 studies · 220 people in trials Very low certainty Immune markers 4 studies · 166 people in trials Low certainty Gum health and dental plaque (mouthwash, toothpaste, gel) 7 studies · 264 people in trials Low certainty Mouth bacteria, tooth decay germs and bad breath 5 studies · 274 people in trials Low certainty Fighting germs and infections 3 studies Not enough evidence Cough, asthma and COPD 5 studies Not enough evidence Skin and acne 1 study Not enough evidence Fertility, sperm and PCOS 1 study Not enough evidence Exercise performance and physical fatigue 2 studies · 30 people in trials Not enough evidence Inflammation and uric acid 4 studies · 275 people in trials Not enough evidence Thyroid 1 study · 44 people in trials Not enough evidence

Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).

How we rate evidence

High certainty

Several well-run trials or reviews agree; further research is unlikely to change the picture much.

Moderate certainty

Good trials point the same way, but some doubt remains.

Low certainty

Small, short or inconsistent trials. The finding could change with better research.

Very low certainty

Very little or very weak human data. Treat as a possibility only.

Mixed findings

Trials or reviews disagree with each other.

Not enough evidence

Not enough human research to say either way.

Evidence against

Good research found no benefit, or found harm.

We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We searched PubMed and Europe PMC, read the abstracts of the studies cited, and read the full text of a 2017 systematic review and a 2014 review for history and for trials known only from its table. Plant names were checked in GBIF and NCBI Taxonomy. Pages from NCCIH, Memorial Sloan Kettering, LiverTox, LactMed and the FDA on holy basil could not be found or opened, and whether an EMA herbal monograph exists was not confirmed; all are marked not verified. The classical Ayurvedic verses were not checked at a source. Certainty ratings are the compiler's own reading, not formal grades. No study is cited that we could not verify.

Study library: every study we checked 96

Design Research type Plant part Year from Search

Study	Design	People	Product, dose, length	Result
Agarwal 2011 Comparative evaluation of efficacy of 0.2% Chlorhexidine, Listerine and Tulsi extract mouth rinses on salivary Streptococcus mutans count of high school children--RCT. Contemp Clin Trials · PMID 21763461 · DOI	Controlled trial	45 School children aged 14 to 15, India	4% tulsi extract mouth rinse Rinse twice daily for 1 minute for 7 days, then once on day 8 8 days per phase, crossover with 15-day washouts · vs 0.2% chlorhexidine and Listerine rinses	All three rinses lowered S. mutans counts; the differences between rinses did not reach statistical significance. No significant difference between tulsi, chlorhexidine and Listerine Methods, limits and funding Outcomes: Salivary Streptococcus mutans (a tooth-decay bacterium) count Limitations: Short, small; a bacteria count is not the same as fewer cavities. Read: abstract
Agrawal 1996 Randomized placebo-controlled, single blind trial of holy basil leaves in patients with noninsulin-dependent diabetes mellitus. Int J Clin Pharmacol Ther · PMID 8880292	Controlled trial	40 Adults with non-insulin-dependent (type 2) diabetes, India (the review lists 40 people, ages 41-65)	Holy basil leaves (Ocimum sanctum; the review lists leaf powder 2.5 g a day in the morning before a meal) leaf About 2.5 g a day (dose from the review table, not the abstract) About 5 weeks per phase, crossover (about 5 weeks with a 5-day washout, per the review) · vs Placebo leaves (the review lists spinach leaf powder 2.5 g a day)	Fasting blood sugar fell by 21.0 mg/dl with holy basil compared with placebo (17.6% lower); after-meal blood sugar fell by 15.8 mg/dl (7.3% lower). Urine sugar showed a similar trend. Total cholesterol showed a mild reduction. Fasting glucose difference -21.0 mg/dl (p<0.001); after-meal glucose -15.8 mg/dl (p<0.02) (Fasting: -31.4 to -11.2 mg/dl; after meal: -27.0 to -5.6 mg/dl) Methods, limits and funding Outcomes: Fasting and after-meal blood sugar, total cholesterol, urine sugar Limitations: Single-blind (the researchers knew who got what), small, short, 1996; the abstract does not state how many people finished or whether diabetes drugs were changed. Cholesterol change was described only as mild. Read: abstract
Agrawal 2024 Assessment of the Efficiency of Tulsi Extract as a Locally Administered Medication Agent and Its Comparison With Curcumin in the Treatment of Periodontal Pockets. Cureus · PMID 38523946 · DOI	Controlled trial	Adults with gum pockets (30 sites per group)	Tulsi extract placed in the gum pocket after cleaning Local application 30 days · vs Cleaning alone and cleaning plus curcumin gel	All three groups improved. The enzyme test fell more with tulsi than with curcumin, but plaque and gum scores fell slightly more with curcumin. The authors conclude tulsi and curcumin worked about the same. Similar to curcumin; numbers not in the abstract Methods, limits and funding Outcomes: Bacterial enzyme test (BAPNA), bleeding, gum and plaque scores, attachment level, pocket depth Limitations: Counted by gum site, not by person, so the true number of people is unclear; 30 days. Read: abstract
Ahmad 2012 Novel Ocimumoside A and B as anti-stress agents: modulation of brain monoamines and antioxidant systems in chronic unpredictable stress model in rats Phytomedicine · PMID 22455995 · DOI	Animal research animal			Methods, limits and funding Read: abstract
Ahmad et al. 2013 Ahmad 2013 (as tabulated in Jamshidi & Cohen 2017) Reported in Jamshidi & Cohen 2017 table · Source	Controlled trial	200 Adults with gouty arthritis	Tulsi tincture (a commercial tincture) leaf 10 drops three times a day 12 weeks · vs Wild rosemary tincture, 10 drops three times a day	The review table says serum uric acid fell significantly. Lower uric acid; no numbers Methods, limits and funding Outcomes: Serum uric acid Limitations: Known only from the one-line summary in the Jamshidi and Cohen 2017 review table; the original paper was not located in PubMed or read for this profile, so details may be incomplete. Read: summary-only
Ahmed 2002 Reversible anti-fertility effect of benzene extract of Ocimum sanctum leaves on sperm parameters and fructose content in rats. Journal of basic and clinical physiology and pharmacology · PMID 12099405 · DOI	Animal research animal	Albino rats (male)	Benzene extract of Ocimum sanctum leaves (a solvent extract not used in teas or supplements) leaf 250 mg/kg body weight 48 days · vs Untreated control	Total sperm count, motility and forward velocity fell, abnormal sperm rose and fructose fell. All values returned to normal 2 weeks after treatment stopped. Authors attribute this to an anti-androgenic effect. Reduced sperm count and motility; reversible (Not given) Methods, limits and funding Outcomes: Sperm count, motility, abnormal sperm, fructose Limitations: Benzene extract (not a food or supplement form); rats; one dose; sample size not in abstract. Read: abstract
Alharbi 2024 Effect of eugenol on cytochrome P450 1A2, 2C9, 2D6, and 3A4 activity in human liver microsomes Saudi Pharm J · PMID 38841106 · DOI	Laboratory research in-vitro			Methods, limits and funding Read: abstract
Anandjiwala 2006 Quantification of eugenol, luteolin, ursolic acid, and oleanolic acid in black (Krishna Tulasi) and green (Sri Tulasi) varieties of Ocimum sanctum Linn. using HPTLC J AOAC Int · PMID 17225591	Phytochemical analysis n/a			Methods, limits and funding Read: abstract
Baba 2005 Absorption, metabolism, degradation and urinary excretion of rosmarinic acid after intake of Perilla frutescens extract in humans Eur J Nutr · PMID 15309457 · DOI	Pharmacokinetic	6		Methods, limits and funding Read: abstract
Balaji 2024 Development of an allele-specific PCR (AS-PCR) method for identifying high-methyl eugenol-containing purple Tulsi (Ocimum tenuiflorum L.) in market samples. Molecular biology reports · PMID 38520476 · DOI	Other other	30 30 tulsi powder samples bought on the Indian market	Market tulsi powders tested by DNA (allele-specific PCR) leaf powder	80% of market samples were purple tulsi, 3.5% green tulsi, about 10% mixtures and two samples (6.5%) were not O. tenuiflorum but O. gratissimum. The authors say purple tulsi has higher methyl eugenol, which they describe as moderately toxic and potentially carcinogenic. 6.5% wrong species (Not given) Methods, limits and funding Outcomes: Identified green tulsi, purple tulsi and other species Limitations: Only 30 samples from one market; the methyl eugenol claim is stated by the authors, and the abstract does not give measured levels or human risk. Read: abstract
Bhamra 2022 The Cultural and Commercial Value of Tulsi (Ocimum tenuiflorum L.): Multidisciplinary Approaches Focusing on Species Authentication. Plants (Basel, Switzerland) · PMID 36432888 · DOI	Other other	33 vouchered Ocimum specimens and 47 commercial samples in the UK	DNA barcoding of tulsi unspecified	Found a potential species substitution of O. gratissimum for O. tenuiflorum among households in the South Asian community. Commercial samples (47) were difficult to authenticate, probably because manufacturing degraded the DNA. Substitution found; commercial products hard to verify (Not given) Methods, limits and funding Outcomes: Authentication Limitations: Sample count (33 + 47 = 80) is the sum of two groups; barcoding of processed products often fails. Read: abstract
Bhargava et al. 2013 Bhargava 2013 (as tabulated in Jamshidi & Cohen 2017) Reported in Jamshidi & Cohen 2017 table · Source	Clinical trial	50 Women aged 18 to 30 with low blood pressure (hypotension)	Fresh juice of 15 tulsi leaves leaf Twice a day 4 weeks	The review table says blood pressure changed significantly; this group had LOW blood pressure to begin with, so the direction is not stated in the review. Change in blood pressure; direction not stated Methods, limits and funding Outcomes: Blood pressure Limitations: Known only from the one-line summary in the Jamshidi and Cohen 2017 review table; the original paper was not located in PubMed or read for this profile, so details may be incomplete. Read: summary-only
Bhat 2010 In vivo enhancement of natural killer cell activity through tea fortified with Ayurvedic herbs. Phytother Res · PMID 19504465 · DOI	Controlled trial	142 Healthy adults aged 55 or older in India with low natural killer (NK) cell activity and a history of recurrent coughs and colds (two studies, 32 and 110 people)	A tea fortified with five Ayurvedic herbs: ashwagandha, licorice, ginger, tulsi (Ocimum sanctum) and cardamom mixed herbs · vs Regular tea	NK cell activity was higher after the fortified tea than after regular tea in the pilot (32 people) and in a crossover study (110 people). Higher NK cell activity; no numbers in the abstract Methods, limits and funding Outcomes: Ex vivo natural killer cell activity Limitations: Five herbs in one tea, so tulsi's own part cannot be separated. Industry-run (Unilever). Lab marker only; no infections were counted in the abstract. Funding and conflicts: Authors are from Unilever research; funding not stated in the abstract. Read: abstract
Bhattacharyya 2008 Controlled programmed trial of Ocimum sanctum leaf on generalized anxiety disorders. Nepal Med Coll J · PMID 19253862	Clinical trial uncontrolled	35 35 hospital patients with generalized anxiety disorder (21 men, 14 women, average age 38.4)	Ocimum sanctum leaf extract (described as plant extract) capsules leaf 500 mg capsule twice daily after meals 60 days (assessed at day 0, 30, 60)	Anxiety significantly reduced (p<0.001) along with related stress and depression; attention and willingness to adjust improved (p<0.001). Scale scores and effect sizes not given in the abstract (null) Methods, limits and funding Outcomes: Anxiety, stress and depression rating scales; attention and willingness to adjust Limitations: Abstract only. One group of 35 treated people, and the abstract describes no placebo or comparison group, so improvement cannot be attributed to the herb. Small, from one hospital; the exact preparation is not described. Read: abstract
Bhattarai 2024 A Comprehensive Review of the Phytochemical Constituents and Bioactivities of Ocimum tenuiflorum ScientificWorldJournal · PMID 39473808 · DOI	Narrative review n/a			Methods, limits and funding Read: abstract
Biswas 2022 Efficacy of topical tulsi (Ocimum sanctum) paste for the management of oral submucous fibrosis - A clinical study. Indian J Dent Res · PMID 36254950 · DOI	Clinical trial	60 People with oral submucous fibrosis (a gum and cheek stiffening disease linked to betel nut chewing), India	Tulsi (Ocimum sanctum) paste applied inside the mouth Topical paste (frequency not stated) 3 months	Burning fell and mouth opening improved in all three groups over 3 months. Improvement over time; no comparison group Methods, limits and funding Outcomes: Burning sensation (pain scale) and mouth opening Limitations: No control group, so improvement cannot be credited to tulsi alone. Read: abstract
Chandrasekaran 2013 Evaluation of the mutagenic potential and acute oral toxicity of standardized extract of Ocimum sanctum (OciBest™). Human & experimental toxicology · PMID 23424203 · DOI	Animal research animal	Salmonella bacteria, cultured cells; rats	OciBest standardised Ocimum sanctum extract leaf Up to 5 g/kg once in rats; 7.9 to 2,500 micrograms/mL in test tube 14 days observation · vs Control	No mutations or chromosome damage in the standard test battery. Rats given 5 g/kg showed no treatment-related toxic effects over 14 days. Not genotoxic; no acute toxicity at 5 g/kg (Not given) Methods, limits and funding Outcomes: Mutagenicity, acute toxicity Limitations: Single manufacturer extract; acute only. Read: abstract
Chang 2024 Eugenol: A Potential Modulator of Human Platelet Activation and Mouse Mesenteric Vascular Thrombosis via an Innovative cPLA2-NF-κB Signaling Axis. Biomedicines · PMID 39200154 · DOI	Laboratory research in-vitro	Human platelets from healthy donors; mice	Eugenol (pure compound) Not given in the part read Acute · vs Control	Eugenol inhibited collagen-triggered platelet signalling and, per the abstract, showed anti-thrombotic potential in mouse vessels. Antithrombotic action in mice (Not given) Methods, limits and funding Outcomes: Platelet signalling; clot formation in mouse vessels Limitations: Pure eugenol, not tulsi; cut-off sentence in the abstract read; mouse and test-tube data. Read: abstract
Checked by the author of this file 2026 Check for NCCIH, EMA/HMPC, Memorial Sloan Kettering and LactMed pages on holy basil Agency web pages (checked 2026-10-25) · Source	Authoritative guidance		Holy basil (Ocimum tenuiflorum) unspecified	Guessed NCCIH and Memorial Sloan Kettering holy basil pages returned page-not-found. The EMA site refused automated access (a security check page), so whether an EU herbal monograph exists was not confirmed. A search of the NCBI Bookshelf for holy basil or tulsi lactation entries returned nothing. Not finding a page does not prove none exists. Methods, limits and funding Outcomes: Existence of an agency or reference entry Limitations: Nothing in this record is agency guidance. It only documents what could not be found. Read: summary-only
Chutimanukul 2022 Physiological responses and variation in secondary metabolite content among Thai holy basil cultivars (Ocimum tenuiflorum L.) grown under controlled environmental conditions in a plant factory Front Plant Sci · PMID 36340360 · DOI	Phytochemical analysis n/a	12		Methods, limits and funding Read: abstract
Cohen 2014 Tulsi - Ocimum sanctum: A herb for all reasons. J Ayurveda Integr Med · PMID 25624701 · DOI	Narrative review	Narrative review of laboratory, animal and human research on tulsi	Tulsi (various) unspecified Various Various · vs Various	Author concludes research supports effects on psychological stress through memory and cognitive effects and anxiety-reducing and antidepressant-like properties. None (narrative) Methods, limits and funding Outcomes: Stress, memory, mood, metabolic and antimicrobial effects Limitations: Abstract only. Narrative, not systematic; author discloses being paid as consultant and adviser to Organic India, a tulsi product maker. Much of the antidepressant and anxiety-reducing evidence is from animals. Funding and conflicts: Author consultant to Organic India (declared in the article) Read: abstract
Dash 2024 Raw Ocimum sanctum L. leaf extract modulates the pharmacokinetic of ceftriaxone and increases its bioavailability in staphylococcal mastitis. Indian journal of pharmacology · PMID 39687955 · DOI	Animal research animal	Goats with experimentally caused chronic udder infection	Fresh raw Ocimum sanctum leaf juice with intravenous ceftriaxone leaf juice 5 ml/kg by mouth for 7 days 7 days · vs Ceftriaxone alone	Leaf juice increased ceftriaxone bioavailability and slowed its elimination. Higher antibiotic exposure (Not given) Methods, limits and funding Outcomes: Antibiotic blood and milk levels Limitations: Goats, very large juice dose per kg, injected antibiotic; shows plausibility only. Read: abstract
Debong 2024 Linalool, 1,8-Cineole, and Eugenol Transfer from a Curry Dish into Human Urine Mol Nutr Food Res · PMID 37953385 · DOI	Pharmacokinetic	18		Methods, limits and funding Read: abstract
Deepika 2021 Comparative clinical data for gingivitis treatment using gels from Ocimum sanctum (Tulsi) and chlorhexidine (CHX). Bioinformation · PMID 35291347 · DOI	Controlled trial	30 Adults with gingivitis	2% tulsi gel placed on the gums Gel advised for 1 month 1 month · vs Chlorhexidine gel (15 per group)	Gum index and pocket depth did not change significantly in either group. The plaque index and attachment loss improved in the tulsi group. The authors call the gel promising. Mixed; mostly p-values; no numbers in the abstract Methods, limits and funding Outcomes: Gingival index, plaque index, pocket depth, attachment loss Limitations: Only 30 people; the abstract's p-values are hard to read as a clear win; small and short. Read: abstract
Devra et al. 2012 Devra 2012 (as tabulated in Jamshidi & Cohen 2017) Reported in Jamshidi & Cohen 2017 table · Source	Controlled trial	100 Adults aged 40 or older with metabolic syndrome	Aqueous tulsi leaf preparation leaf 5 mL twice a day before meals 12 weeks · vs Not disclosed in the review (described as placebo-controlled)	The review table says lipid profile, fasting blood glucose and blood pressure improved. Improvement; no numbers Methods, limits and funding Outcomes: Blood fats, fasting blood sugar, blood pressure Limitations: Known only from the one-line summary in the Jamshidi and Cohen 2017 review table; the original paper was not located in PubMed or read for this profile, so details may be incomplete. Read: summary-only
Dineshkumar et al. 2010 Dineshkumar 2010 (as tabulated in Jamshidi & Cohen 2017) Reported in Jamshidi & Cohen 2017 table · Source	Controlled trial	40 Adults aged 45 to 55 with type 2 diabetes	Aqueous tulsi leaf preparation leaf Printed as '500 g/day' in the review table, which looks like a typing error, so the dose is treated as unknown 8 weeks · vs Water (placebo)	The review table says lipid profile improved; it was one of the better-rated studies (Jadad score 3 in the review). Improvement; no numbers Methods, limits and funding Outcomes: Blood fats Limitations: Known only from the one-line summary in the Jamshidi and Cohen 2017 review table; the original paper was not located in PubMed or read for this profile, so details may be incomplete. Read: summary-only
GBIF Secretariat 2026 GBIF Backbone: Ocimum tenuiflorum L. (usageKey 2927100) GBIF Backbone Taxonomy · Source	Reference database n/a			Methods, limits and funding Read: full-text
Gandhi et al. 2016 Gandhi 2016 (as tabulated in Jamshidi & Cohen 2017) Reported in Jamshidi & Cohen 2017 table · Source	Controlled trial	40 Men aged 45 to 55 with type 2 diabetes	Tulsi leaf capsules leaf 3 g a day before meals About 6.5 weeks · vs Not disclosed	The review table says both fasting and after-meal blood sugar fell significantly. Improvement; no numbers Methods, limits and funding Outcomes: Fasting and after-meal blood sugar Limitations: Known only from the one-line summary in the Jamshidi and Cohen 2017 review table; the original paper was not located in PubMed or read for this profile, so details may be incomplete. Read: summary-only
Gautam 2014 Toxicological Study of Ocimum sanctum Linn Leaves: Hematological, Biochemical, and Histopathological Studies. Journal of toxicology · PMID 24616736 · DOI	Animal research animal	Mice (acute) and rats (28 days)	50% ethanolic O. sanctum leaf extract leaf Acute 200, 600, 2,000 mg/kg in mice; 200, 400, 800 mg/kg a day for 28 days in rats 14 days acute; 28 days · vs Control	No deaths or toxic signs; no changes in blood counts, chemistry or organ tissue (liver, kidney, spleen, heart, testis, ovary). No toxicity at doses tested (Not given) Methods, limits and funding Outcomes: Behaviour, deaths, blood tests, organ pathology Limitations: Short; animals; doses given in mg per kg of extract. Read: abstract
Gertsch 2008 Beta-caryophyllene is a dietary cannabinoid Proc Natl Acad Sci U S A · PMID 18574142 · DOI	In vitro+animal animal			Methods, limits and funding Read: abstract
Giang Le 2024 Essential Oil and Waste Hydrosol of Ocimum Tenuiflorum L.: A Low-Cost Raw Material Source of Eugenol, Botanical Pesticides, and Therapeutic Potentiality Chem Biodivers · PMID 39073007 · DOI	Phytochemical analysis n/a	4		Methods, limits and funding Read: abstract
Gowda 2023 Ocimum tenuiflorum extract (HOLIXER): Possible effects on hypothalamic-pituitary-adrenal (HPA) axis in modulating stress. PLoS One · PMID 37141281 · DOI	Animal research animal	Mice, rats and cell assays	Holixer, standardised Ocimum tenuiflorum extract unspecified Single experiments · vs Controls	In animals the extract increased swimming time, reduced immobility and prevented a rise in corticosterone. In cell tests it inhibited cortisol release and blocked the CRF1 stress receptor. Not given in the abstract (null) Methods, limits and funding Outcomes: Swim endurance and forced-swim immobility; corticosterone; cortisol release and CRF1 receptor activity in cells Limitations: Abstract only. Animal and cell work only; written by employees of the extract maker. The journal has a 2026 erratum which was not read. Funding and conflicts: Authors employed by Natural Remedies (extract maker) Read: abstract
Guenette 2007 Pharmacokinetics of eugenol and its effects on thermal hypersensitivity in rats Eur J Pharmacol · PMID 17321520 · DOI	Pharmacokinetic animal	6		Methods, limits and funding Read: abstract
Gupta 2007 Constituents of Ocimum sanctum with antistress activity J Nat Prod · PMID 17850106 · DOI	Animal research animal			Methods, limits and funding Read: abstract
Huang 2024 Eugenol Suppresses Platelet Activation and Mitigates Pulmonary Thromboembolism in Humans and Murine Models. International journal of molecular sciences · PMID 38396774 · DOI	Laboratory research in-vitro	Human platelets from healthy donors; mice	Eugenol (pure compound from clove oil, not tulsi itself) 2 micromolar inhibited aggregation induced by collagen and arachidonic acid Acute · vs Control	At 2 micromolar eugenol reduced collagen- and arachidonic-acid-induced platelet clumping; thrombin- and U46619-induced clumping was unaffected. In mice it reduced clots in lung vessels without lengthening bleeding time. Inhibits aggregation in test tube (Not given) Methods, limits and funding Outcomes: Platelet aggregation, bleeding time in mice Limitations: Pure eugenol from clove, not tulsi extract; tulsi leaf eugenol content and blood levels after use not shown; mouse bleeding time was not prolonged, which argues against a strong bleeding effect. Read: abstract
Jain 2022 Antibacterial efficacy of manuka honey, ocimum sanctum, curcuma longa and 0.2% chlorhexidine mouthwash on the level of streptococcus mutans and lactobacillus acidophilus - A randomized controlled trial. Indian J Dent Res · PMID 36254954 · DOI	Controlled trial	80 Dental students, India	Tulsi (Ocimum sanctum) mouthrinse (also manuka honey, turmeric, chlorhexidine groups) 10 ml twice daily 2 weeks · vs 0.2% chlorhexidine and other herbal rinses; 20 per group	Oral hygiene scores and both bacteria counts fell in all four groups, including tulsi. All rinses lowered counts; no numbers in the abstract Methods, limits and funding Outcomes: Oral hygiene score and counts of S. mutans and Lactobacillus acidophilus in saliva Limitations: Healthy students; 2 weeks; no no-rinse group stated. Read: abstract
Jamshidi 2017 The Clinical Efficacy and Safety of Tulsi in Humans: A Systematic Review of the Literature. Evid Based Complement Alternat Med · PMID 28400848 · DOI	Systematic review	24 human studies of tulsi on metabolic disorders, cardiovascular disease, immunity and neurocognition	Tulsi (various preparations) unspecified Various Various · vs Various	All 24 studies reported favourable outcomes and none reported significant adverse events. The authors say the results suggest tulsi may help lifestyle-related chronic disease including diabetes, metabolic syndrome and psychological stress, but that mechanisms, dose, dose form and best populations need further study. No pooled numbers in the abstract (null) Methods, limits and funding Outcomes: Clinical outcomes after ingesting tulsi, including psychological stress Limitations: Abstract only. Not a meta-analysis; no formal risk-of-bias rating or GRADE given in the abstract. Included theses and conference papers. All studies were reported as favourable, which can signal publication bias. Read: abstract
Jothie Richard 2016 Anti-stress Activity of Ocimum sanctum: Possible Effects on Hypothalamic-Pituitary-Adrenal Axis Phytother Res · PMID 26899341 · DOI	Animal+in vitro animal			Methods, limits and funding Read: abstract
Jürges 2018 Product authenticity versus globalisation-The Tulsi case. PloS one · PMID 30475878 · DOI	Other other	Ocimum plants	Chloroplast DNA markers and chemical profiles of tulsi types leaf	Rama and Krishna tulsi belong to O. tenuiflorum; Vana tulsi belongs to a different genetic group (haplotype I), and the chemical profile differs with genetics. The authors built a test to tell Vana tulsi apart. Different tulsi types differ in genes and chemistry (Not given) Methods, limits and funding Outcomes: Genetic and chemical authentication Limitations: Does not test safety directly; shows that products called tulsi can be chemically different. Read: abstract
Kamran 2023 Effect of Plant-Based Mouthwash (Morinda citrifolia and Ocimum sanctum) on TNF-α, IL-α, IL-β, IL-2, and IL-6 in Gingival Crevicular Fluid and Plaque Scores of Patients Undergoing Fixed Orthodontic Treatment. Medicina (Kaunas) · PMID 38004017 · DOI	Controlled trial	75 Adults with fixed braces (orthodontic treatment)	4% Ocimum sanctum mouthwash (also 5% noni, Morinda citrifolia, and 0.12% chlorhexidine groups) Mouthwash on top of fluoride toothpaste and brushing · vs Chlorhexidine and noni mouthwashes	Adding a mouthwash lowered plaque scores. TNF-alpha, IL-1 alpha and IL-1 beta fell in herbal mouthwash users. The authors say tulsi (and noni) can be an alternative to chlorhexidine. Lower plaque and gum-fluid inflammation markers; numbers not in the abstract Methods, limits and funding Outcomes: Plaque score; inflammatory chemicals (TNF-alpha, IL-1 alpha and beta, IL-2, IL-6) in gum fluid Limitations: Duration not given in the abstract; not clear how many were in each group. Read: abstract
Kasinathan 1972 Antifertility effect of Ocimum sanctum L. Indian journal of experimental biology · PMID 4344433	Animal research animal	Not available	Ocimum sanctum L. unspecified Not available Not available · vs Not available	Only the title (Antifertility effect of Ocimum sanctum L., 1972) was read; no abstract in PubMed, so the findings are not known. Not available (Not available) Methods, limits and funding Outcomes: Fertility Limitations: Result not read. Cited only to show that this study exists. Read: summary-only
Kelm 2000 Antioxidant and cyclooxygenase inhibitory phenolic compounds from Ocimum sanctum Linn. Phytomedicine · PMID 10782484 · DOI	Laboratory research in-vitro			Methods, limits and funding Read: abstract
Khan 2011 Thrombolytic potential of Ocimum sanctum L., Curcuma longa L., Azadirachta indica L. and Anacardium occidentale L. Journal of basic and clinical pharmacy · PMID 24826011	Laboratory research in-vitro	Human blood clots in a test-tube model	Aqueous Ocimum sanctum extract unspecified Not given · vs Streptokinase (positive control); water	O. sanctum extract dissolved 30.01 +/- 6.168% of clot, versus 86.2 +/- 10.7% for streptokinase. 30.01% clot lysis (SD 6.168) Methods, limits and funding Outcomes: Percent clot dissolving Limitations: Test-tube clot-lysis model only; no in-body or bleeding data. Read: abstract
Khanna 1986 Effect of long term feeding of tulsi(Ocimum sanctum Linn) on reproductive performance of adult albino rats. Indian journal of experimental biology · PMID 3770821	Animal research animal	Adult albino rats	Tulsi (Ocimum sanctum) fed long term unspecified Not available Long term · vs Not available	Only the title was read; no abstract is in PubMed, so the result is not known. Not available (Not available) Methods, limits and funding Outcomes: Reproductive performance Limitations: Result not read. Cited only to show that this study exists. Read: summary-only
Kochhar et al. 2009 Kochhar 2009 (as tabulated in Jamshidi & Cohen 2017) Reported in Jamshidi & Cohen 2017 table · Source	Controlled trial	90 Men aged 40 to 60 with type 2 diabetes or metabolic syndrome	Tulsi leaf powder leaf 2 g a day 12 weeks · vs Neem alone vs neem plus tulsi (comparator as given in the review)	The review table says thirst, hunger and blood pressure improved. Improvement; no numbers Methods, limits and funding Outcomes: Diabetes symptoms, blood pressure Limitations: Known only from the one-line summary in the Jamshidi and Cohen 2017 review table; the original paper was not located in PubMed or read for this profile, so details may be incomplete. Read: summary-only
Kothari 2004 Essential oil yield and quality of methyl eugenol rich Ocimum tenuiflorum L.f. (syn. O. sanctum L.) grown in south India as influenced by method of harvest. Journal of chromatography. A · PMID 15553132 · DOI	Other other	Field-grown methyl eugenol-rich Ocimum tenuiflorum in India	Essential oil aerial parts 1 year of harvests	Describes a methyl eugenol-rich O. tenuiflorum type; shoot cuts at 30 cm gave oil with the highest methyl eugenol. Methyl eugenol-rich chemotype exists (Not given) Methods, limits and funding Outcomes: Essential oil yield and make-up Limitations: Agricultural study; does not assess safety. Read: abstract
Kumar 2010 Chemical composition, antifungal and antiaflatoxigenic activities of Ocimum sanctum L. essential oil and its safety assessment as plant based antimicrobial. Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association · PMID 19909781 · DOI	Animal research animal	Mice; fungi	Ocimum sanctum essential oil and eugenol leaf essential oil LD50 4,571.43 microlitres per kg in mice Acute	The oil's LD50 in mice was 4,571.43 microlitres per kg, which the authors call non-toxic to mammals. LD50 4,571.43 microlitres/kg (Not given) Methods, limits and funding Outcomes: Antifungal activity; mouse lethal dose Limitations: Acute test in mice; not repeated-dose, not human. Read: abstract
Kumar 2016 Evaluation of the synergistic effect of Allium sativum, Eugenia jambolana, Momordica charantia, Ocimum sanctum, and Psidium guajava on hepatic and intestinal drug metabolizing enzymes in rats. Journal of intercultural ethnopharmacology · PMID 27757267 · DOI	Animal research animal	Sprague-Dawley rats	Polyherbal formulation containing garlic, jamun, bitter melon, Ocimum sanctum and guava (not tulsi alone) mixed Several doses Several doses; time-dependent · vs Control	The five-herb mixture raised the activity of phase II enzymes (UDP-glucuronyltransferase, glutathione S-transferase) with doses and time and altered some CYP levels, but CYP3A mRNA did not rise. Authors say it might cause herb-drug interactions. Phase II enzyme activity increased (Not given) Methods, limits and funding Outcomes: Liver and gut drug-metabolising enzymes (CYP and phase II) Limitations: The mixture contains five herbs, so effects cannot be pinned on tulsi; rats. Read: abstract
Kumar 2017 Evaluation of the potential effect of Allium sativum, Momordica charantia, Eugenia jambolana, Ocimum sanctum, and Psidium guajava on intestinal p-glycoprotein in rats. Journal of intercultural ethnopharmacology · PMID 28163963 · DOI	Animal research animal	Sprague-Dawley rats	Same five-herb polyherbal formulation as above mixed 50, 100 and 200 mg/kg a day 1 to 4 weeks · vs Control	The mixture lowered P-glycoprotein expression and pump activity after 1 week, which the authors say might change how much of some antidiabetic drugs is absorbed. P-gp mRNA down 1.75 to 2.45 fold (Not given) Methods, limits and funding Outcomes: Intestinal P-glycoprotein (drug pump) expression and activity Limitations: Five-herb mixture, rats; cannot attribute to tulsi. Read: abstract
Lopresti 2022 A randomized, double-blind, placebo-controlled trial investigating the effects of an Ocimum tenuiflorum (Holy Basil) extract (Holixer) on stress, mood, and sleep in adults experiencing stress. Front Nutr · PMID 36185698 · DOI	Controlled trial	100 100 adults aged 18 to 65 experiencing stress	Holixer, a standardised Ocimum tenuiflorum extract unspecified 125 mg twice daily 8 weeks · vs Placebo	Greater improvement than placebo in Perceived Stress Scale (p = 0.003) and Athens Insomnia Scale (p = 0.025); lower hair cortisol at week 8 (p = 0.025); after the lab stress test, lower salivary cortisol (p = 0.001), salivary amylase (p = 0.001), systolic (p = 0.010) and diastolic (p = 0.025) blood pressure and subjective stress (p < 0.001). Well tolerated, no major adverse effects. The authors note the sleep findings are subjective and need confirming with gold-standard sleep measures. Group differences given only as p-values in the abstract; effect sizes not stated (null) Methods, limits and funding Outcomes: Perceived Stress Scale (primary), Profile of Mood States, Athens Insomnia Scale, Restorative Sleep Questionnaire, PROMIS-29, Fitbit sleep tracking, hair cortisol, and salivary cortisol, salivary amylase, blood pressure and subjective stress after the Maastricht Acute Stress Test Limitations: Abstract only. Fitbit sleep results and Profile of Mood States results are not reported in the abstract. Funded by the extract maker (Natural Remedies Pty Ltd); the funder says it was not involved in design, analysis or reporting. Registered ACTRN12621000609853. Funding and conflicts: Funding from Natural Remedies Pty Ltd, the Holixer manufacturer Read: abstract
Lopresti 2022 Modulation of the hypothalamic-pituitary-adrenal (HPA) axis by plants and phytonutrients: a systematic review of human trials. Nutr Neurosci · PMID 33650944 · DOI	Systematic review	52 randomised human trials of single herbs or plant nutrients on stress hormones (including holy basil)	Many plants, including holy basil unspecified Various Various · vs Control	The authors say that for most plants, including holy basil, the effect on stress-hormone activity in humans was unclear; the most consistent finding was a morning cortisol-lowering effect of ashwagandha. None for holy basil in the abstract (null) Methods, limits and funding Outcomes: Cortisol, cortisone, CRH, ACTH in blood, saliva, urine or hair Limitations: Abstract only. The abstract names holy basil among the 26 plants studied but gives no holy-basil-specific result. The review searched until October 2020, so it predates the 2022 Holixer trial. Read: abstract
Maaz 2026 Protective Effects of the Ethanolic Leaf Extract of Ocimum sanctum L. on Collagen-Induced Human Platelet Aggregation and CCl4-Induced Hepatotoxicity in Rats: Molecular Docking Analysis of Platelet Activation Signaling Targets. Molecules (Basel, Switzerland) · PMID 42653832 · DOI	Laboratory research in-vitro	Human platelets in test tubes; carbon-tetrachloride liver injury in rats	Ethanolic Ocimum sanctum leaf extract leaf 1 to 10 mg/mL on platelets · vs Control	The extract dose-dependently reduced collagen-induced human platelet aggregation, P-selectin and calcium release in the test tube. In rats it reduced rises in liver enzymes caused by carbon tetrachloride. Dose-dependent inhibition of aggregation (Not given) Methods, limits and funding Outcomes: Collagen-induced platelet aggregation, liver enzymes Limitations: Test-tube concentrations of 1 to 10 mg/mL may not be reached in blood after drinking tea or taking capsules; no bleeding outcome tested. Published 2026 so not yet widely replicated. Read: abstract
McKinney 2026 Effects of multi-herb and ashwagandha root formulas on stress modulation: a randomized, double-blind, placebo-controlled clinical study. Trials · PMID 41656269 · DOI	Controlled trial	186 186 adults aged 18 to 65 with high stress, BMI 18 to 29.9	Multi-herb formula VL-G-A57 containing Rhodiola, holy basil and Schisandra chinensis (and a separate ashwagandha formula) unspecified 60 days · vs Placebo	At day 60 the three-herb formula lowered Perceived Stress Scale scores versus placebo (p < 0.0001); improved PSQI (p = 0.0008), restorative sleep (p < 0.0001), mood dysregulation (p = 0.0454) and anxiety (p = 0.0004). No difference in mental alertness. Only p-values in the abstract (null) Methods, limits and funding Outcomes: Perceived Stress Scale (primary); sleep quality, fatigue, restorative sleep, mental alertness, mood, anxiety Limitations: Abstract only. Holy basil is one of three herbs, so the result cannot be credited to holy basil alone. Two of the authors work for Gaia Herbs, which makes the products. Funding and conflicts: Authors from Gaia Herbs (product maker); see article for funding Read: abstract
Megalaa 2018 A comparative evaluation of the anticaries efficacy of herbal extracts (Tulsi and Black myrobalans) and sodium fluoride as mouthrinses in children: A randomized controlled trial. Indian J Dent Res · PMID 30589005 · DOI	Controlled trial	60 Children and young people at high risk of tooth decay, India	4% tulsi leaf ethanolic mouthrinse leaf Rinse for 7 days 7 days · vs 0.05% sodium fluoride rinse and a 2.5% black myrobalan (Terminalia) rinse; 20 each	Saliva pH rose and S. mutans fell in all three groups. The fluoride rinse raised pH more than the herbal rinses. Tulsi lowered S. mutans more than the others at 1 hour and at day 7 the black myrobalan rinse lowered it more. Direction clear; numbers not in the abstract Methods, limits and funding Outcomes: Saliva acidity (pH) and S. mutans count Limitations: Only 7 days; 20 per group; a lab bacteria count, not cavities. Read: abstract
Mondal 2011 Double-blinded randomized controlled trial for immunomodulatory effects of Tulsi (Ocimum sanctum Linn.) leaf extract on healthy volunteers. J Ethnopharmacol · PMID 21619917 · DOI	Controlled trial	24 Healthy adult volunteers, India (22 completed)	Tulsi (Ocimum sanctum) ethanolic leaf extract capsule leaf 300 mg capsule once a day on an empty stomach 4 weeks, crossover · vs Placebo capsule	After 4 weeks of tulsi, blood cultures made more interferon-gamma (p=0.039) and interleukin-4 (p=0.001), and the share of T-helper cells (p=0.001) and NK cells (p=0.017) was higher than with placebo. p-values only; no effect sizes or confidence intervals in the abstract Methods, limits and funding Outcomes: Immune signals measured in blood: interferon-gamma, interleukin-4, T-helper cells, NK cells Limitations: Only 22 healthy volunteers; no illness outcomes (no colds or infections counted); a higher lab value is not proof of better protection. Read: abstract
Mondal et al. 2012 Mondal 2012 (as tabulated in Jamshidi & Cohen 2017) Reported in Jamshidi & Cohen 2017 table · Source	Controlled trial	22 Healthy adults aged 22 to 37	Tulsi ethanolic leaf extract leaf 300 mg a day before food 4 weeks (3-week washout) · vs 300 mg sucrose	The review table says lipid profile fell in 6 of the participants (same trial as the immune-marker trial). Lipids fell in 6 people; no more detail Methods, limits and funding Outcomes: Blood fats Limitations: Known only from the one-line summary in the Jamshidi and Cohen 2017 review table; the original paper was not located in PubMed or read for this profile, so details may be incomplete. Read: summary-only
Mulugeta 2023 Phenotypic Variations and Bioactive Constituents among Selected Ocimum Species Plants (Basel) · PMID 38202372 · DOI	Phytochemical analysis n/a	15		Methods, limits and funding Read: abstract
Murugan 2025 Assessment of genotoxicity and acute oral toxicity of a standardized Ocimum tenuiflorum extract (HolixerTM). Drug and chemical toxicology · PMID 39610007 · DOI	Animal research animal	Bacteria, cultured cells, mice, rats	Holixer standardised O. tenuiflorum extract leaf Up to 5,000 micrograms/plate; 2,000 mg/kg in mice; 5 g/kg in rats Acute · vs Control	No mutations, no chromosome damage in cells or mouse bone marrow; acute oral toxicity not seen up to 5 g/kg. Non-genotoxic and non-toxic acutely (Not given) Methods, limits and funding Outcomes: Genotoxicity, acute toxicity Limitations: Acute testing of one manufacturer extract; no repeated-dose or reproduction testing in the abstract. Funding and conflicts: Study of the manufacturer's extract; funding not recorded here Read: abstract
NCBI Taxonomy 2026 NCBI Taxonomy: Ocimum tenuiflorum (taxid 204149) NCBI Taxonomy database · Source	Reference database n/a			Methods, limits and funding Read: full-text
Nadar 2020 Comparative Evaluation of Efficacy of 4% Tulsi Extract (Ocimum sanctum), Fluoridated and Placebo Dentifrices against Gingivitis and Plaque among 14-15 years School Children in Davangere City, India - A Triple Blinded Randomized Clinical Trial. Contemp Clin Dent · PMID 33110312 · DOI	Controlled trial	84 Schoolchildren aged 14 to 15 with gingivitis, India	Toothpaste with 4% tulsi leaf extract leaf Brushing with the assigned toothpaste (frequency not stated in the abstract) 21 days · vs Fluoride toothpaste and placebo toothpaste	Plaque and gum scores fell significantly between groups at day 21 (P=0.001), with the biggest fall in the 4% tulsi toothpaste group compared with placebo toothpaste. The authors say tulsi and the fluoride toothpaste worked the same. Tulsi toothpaste beat placebo toothpaste; same as fluoride toothpaste Methods, limits and funding Outcomes: Plaque and gum (gingival) scores Limitations: 3 weeks; adolescents only; numbers not in the abstract; frequency of brushing not stated. Read: abstract
Nadig 2005 Study of anti-tussive activity of Ocimum sanctum Linn in guinea pigs. Indian J Physiol Pharmacol · PMID 16170996	Animal research animal	Guinea pigs	Ocimum sanctum extract unspecified Not in the abstract record Not in the abstract record · vs Not available	Only the title, 'Study of anti-tussive activity of Ocimum sanctum in guinea pigs', is available; no abstract was available to read. Not available Methods, limits and funding Outcomes: Cough response Limitations: Title only; no results were read; cannot be cited for any result. Read: summary-only
National Institute of Diabetes and Digestive and Kidney Diseases 2026 LiverTox (NIH) search for holy basil, tulsi, Ocimum NCBI Bookshelf search (checked 2026-10-25) · Source	Authoritative guidance		Holy basil (Ocimum tenuiflorum) unspecified	A search of the NCBI Bookshelf for holy basil, tulsi and Ocimum within LiverTox returned no matching entry. A search for basil returned only annotated bibliographies. So no LiverTox likelihood score for holy basil was found. Methods, limits and funding Outcomes: Existence of an agency or reference entry Limitations: A missing search result is not proof that no entry exists; the LiverTox website itself could not be browsed. Read: summary-only
Nomura 2023 Benefits of basil tea for patients with differentiated thyroid cancer during radioiodine therapy: A randomized controlled trial. Heliyon · PMID 37829808 · DOI	Controlled trial	44 People after thyroid cancer surgery getting radioactive iodine treatment, Japan	Holy basil (Ocimum tenuiflorum) tea leaf 180 ml of tea made from 2.0 g of leaves, after each meal 4 days · vs Distilled water	Anxiety scores fell more with basil tea. Saliva tests showed less rise in cavity-causing bacteria, ammonia, protein and blood. The salivary gland scan suggested better gland washout with basil tea. Group differences (P<0.05); numbers not in the abstract Methods, limits and funding Outcomes: Anxiety score; saliva tests; salivary gland scan Limitations: Only 44 people and 4 days; funded by a spice promotion foundation; this trial is about side effects of radioiodine treatment, not about treating a thyroid condition with tulsi. Funding and conflicts: Funded by the Yamazaki Spice Promotion Foundation. Read: abstract
Panda 1998 Ocimum sanctum leaf extract in the regulation of thyroid function in the male mouse. Pharmacological research · PMID 9721597 · DOI	Animal research animal	Male mice	Ocimum sanctum leaf extract leaf 0.5 g/kg body weight 15 days · vs Control	Serum T4 fell significantly. No marked change in T3, T3/T4 ratio or cholesterol. Authors conclude the extract appears antithyroidic and antioxidant in this model. T4 significantly decreased (p-value in abstract not given) (Not given) Methods, limits and funding Outcomes: Serum T3, T4, cholesterol, liver antioxidant enzymes Limitations: One dose in mice; the dose (0.5 g/kg) is far above a human supplement dose per kg. No human thyroid data found. Read: abstract
Penmetsa 2019 Efficacy of Ocimum sanctum, Aloe vera and chlorhexidine mouthwash on gingivitis: A randomized controlled comparative clinical study. Ayu · PMID 31831965 · DOI	Controlled trial	60 Adults with gingivitis, India	Ocimum sanctum (tulsi) mouthwash Rinse twice daily 1 month (checked at 15 and 30 days) · vs Aloe vera mouthwash and chlorhexidine mouthwash (20 people per group); all had scaling	At 30 days tulsi, aloe vera and chlorhexidine mouthwashes were equally effective at lowering plaque, gum inflammation and bleeding scores. At 15 days, tulsi and aloe were not significantly better than chlorhexidine. No difference from chlorhexidine at 30 days; numbers not in the abstract Methods, limits and funding Outcomes: Plaque index, gingival index, bleeding index Limitations: 20 people per group; no group without any mouthwash is described in the abstract despite the placebo-controlled label; no long-term follow-up; extract strength not stated. Read: abstract
Poli 2019 A comparative study of eugenol and Ocimum sanctum Linn. leaf extract on the antifertility effect in female albino rats. Journal of the Chinese Medical Association : JCMA · PMID 30908416 · DOI	Animal research animal	Female albino rats	Eugenol (99% pure) and Ocimum sanctum leaf extract leaf Extract 500 mg/kg body weight a day by mouth (eugenol 0.4 ml a day) 15 days · vs Control	Extract caused no significant change in cycle length but raised progesterone; eugenol lengthened the cycle and raised estradiol and progesterone. The authors say both reduced ovulation frequency and impaired fertility. Hormone changes (estradiol, progesterone) reported (Not given) Methods, limits and funding Outcomes: Oestrous cycle, estradiol, progesterone Limitations: Rats; fertility itself (pregnancy rate) was not directly measured in the abstract; pure eugenol dose is much larger than eugenol in a cup of tea. Read: abstract
Rahalkar 2021 Determination of efficacy of curcumin and Tulsi extracts as local drugs in periodontal pocket reduction: A clinical and microbiological study. J Indian Soc Periodontol · PMID 34158685 · DOI	Controlled trial	15 Adults with gum pockets, 15 people, split-mouth design	Tulsi gel placed in the gum pocket after cleaning (scaling and root planing, SRP) Single local application 30 days · vs SRP alone and SRP plus curcumin gel (each person had all three sites)	All three treatments improved scores. Compared with cleaning alone, only the bacterial enzyme test was significantly better with tulsi (and plaque index with curcumin). Small extra benefit on one lab test Methods, limits and funding Outcomes: Pocket depth, attachment level, plaque, gum and bleeding scores, and a bacterial enzyme test (BAPNA) Limitations: 15 people; 30 days; mostly the cleaning itself did the work. Read: abstract
Rai et al. 1997 Rai 1997 (as tabulated in Jamshidi & Cohen 2017) Reported in Jamshidi & Cohen 2017 table · Source	Clinical trial	27 Adults aged 45 to 65 with type 2 diabetes or metabolic syndrome	Tulsi leaf powder leaf 1 g a day in the morning before a meal 4 weeks	The review table says lipids, blood sugar, glycated protein/HbA1c and uric acid improved. Improvement; no numbers Methods, limits and funding Outcomes: Blood sugar, blood fats, HbA1c, uric acid Limitations: Known only from the one-line summary in the Jamshidi and Cohen 2017 review table; the original paper was not located in PubMed or read for this profile, so details may be incomplete. Read: summary-only
Raina 2015 Evaluation of subacute toxicity of methanolic/aqueous preparation of aerial parts of O. sanctum in Wistar rats: Clinical, haematological, biochemical and histopathological studies. Journal of ethnopharmacology · PMID 26456329 · DOI	Animal research animal	Wistar rats, 5 per sex per group	Methanolic/aqueous O. sanctum aerial-parts extract aerial parts 250, 500 and 1,000 mg/kg a day 28 days · vs Control	No toxic changes in any dose; only small rises in mean corpuscular haemoglobin at 1,000 mg/kg. Authors conclude no toxicity up to the highest dose. No toxicity up to 1,000 mg/kg (Not given) Methods, limits and funding Outcomes: Body weight, blood counts, chemistry, tissue pathology (liver, kidney, spleen, heart, testis/ovary) Limitations: 28 days only; rats; Group size was 5 per sex per dose. Read: abstract
Rajalakshmi et al.; Das et al. 1986 Rajalakshmi 1986 and Das 1983 (as tabulated in Jamshidi & Cohen 2017) Reported in Jamshidi & Cohen 2017 table · Source	Clinical trial	34 20 people with viral hepatitis (10 g fresh-leaf aqueous extract, 2 to 3 weeks) and 14 with viral encephalitis (2.5 g four times a day, 4 weeks, compared with dexamethasone)	Aqueous extract of fresh tulsi leaves leaf 10 g a day (hepatitis); 2.5 g four times a day (encephalitis) 2 to 4 weeks	The review table says hepatitis symptoms all improved within 2 weeks and survival in encephalitis was higher than in the steroid group. Not interpretable as proof; 1980s small studies, no numbers Methods, limits and funding Outcomes: Symptoms; survival Limitations: Known only from the one-line summary in the Jamshidi and Cohen 2017 review table; the original paper was not located in PubMed or read for this profile, so details may be incomplete. Read: summary-only
Renu 2014 Characterization and functional analysis of eugenol O-methyltransferase gene reveal metabolite shifts, chemotype specific differential expression and developmental regulation in Ocimum tenuiflorum L. Mol Biol Rep · PMID 24420851 · DOI	Phytochemical analysis n/a	7		Methods, limits and funding Read: abstract
Sampath 2015 Holy basil (Ocimum sanctum Linn.) leaf extract enhances specific cognitive parameters in healthy adult volunteers: A placebo controlled study. Indian J Physiol Pharmacol · PMID 26571987	Controlled trial	Healthy adult volunteers (number not stated in abstract)	Ethanolic leaf extract of Ocimum sanctum (EtOS) leaf 300 mg capsule per day 30 days · vs Placebo	Compared with placebo, the extract group improved more on reaction time and error rate of the Sternberg test, and on reaction time of the neutral Stroop task and reaction time and error rate of the Stroop interference task. Salivary cortisol and State-Trait Anxiety Inventory improved over time in the extract group only, but the between-group difference was significant only for P300 latency. No change in heart rate or galvanic skin response. Specific values not given in the abstract (null) Methods, limits and funding Outcomes: Sternberg and Stroop tests, P300 latency, salivary cortisol, State-Trait Anxiety Inventory, heart rate, galvanic skin response Limitations: Abstract only. Number of participants, whether subjects were blinded and any funding are not stated in the abstract. Healthy volunteers, short trial. Placebo group also improved on the cognitive tests during the first 15 days (practice effect). Read: abstract
Sarangi 2017 Pharmacokinetic and pharmacodynamic interaction of hydroalcoholic extract of Ocimum sanctum with valproate. Epilepsy & behavior : E&B · PMID 28867572 · DOI	Animal research animal	Wistar rats	Hydroalcoholic Ocimum sanctum extract with valproate unspecified 200 to 1,000 mg/kg for 14 days; 1,000 mg/kg was the best dose 14 days · vs Valproate alone	Extract alone gave 50% protection against seizures. Combined with valproate there was no significant change in valproate blood levels or its seizure control. No significant pharmacokinetic change (Not given) Methods, limits and funding Outcomes: Seizure protection, valproate blood levels Limitations: Rats; doses far above human use; valproate only. Read: abstract
Sarangi 2020 An interaction study of Ocimum sanctum L. and levetiracetam in pentylenetetrazole kindling model of epilepsy. Journal of ethnopharmacology · PMID 31739106 · DOI	Animal research animal	Adult male Wistar rats with chemically induced chronic seizures	Hydroalcoholic Ocimum sanctum extract with levetiracetam unspecified 1,000 mg/kg with levetiracetam 300 mg/kg 14 days of drug treatment for the interaction test · vs Levetiracetam alone; controls	No significant pharmacokinetic interaction with levetiracetam, apart from a later peak time (Tmax) in the combination group (p=0.009). The combination gave better seizure control than levetiracetam alone in rats. Tmax later; seizure protection 85.72% vs 42.86% (Not given) Methods, limits and funding Outcomes: Seizure scores and drug levels Limitations: Rats, one high dose; seizure-protection results came from a small model; says nothing about human seizure safety. Read: abstract
Sarvaiya 1986 Sarvaiya 1986 (as tabulated in Jamshidi & Cohen 2017) Reported in Jamshidi & Cohen 2017 table · Source	Controlled trial	36 Adults aged 45 to 64 with high blood pressure (two small trials of 20 and 16 people)	Fresh juice with about 75% tulsi leaf 30 mL a day (crossover trial, 10 days); 30 mL twice a day (12 days) 10 to 12 days · vs Green-coloured water	The review table says blood pressure fell significantly with tulsi juice (about 25% lower in the second trial). Blood pressure fell; no more detail Methods, limits and funding Outcomes: Blood pressure Limitations: Known only from the one-line summary in the Jamshidi and Cohen 2017 review table; the original paper was not located in PubMed or read for this profile, so details may be incomplete. Read: summary-only
Satapathy 2017 Effect of Tulsi (Ocimum sanctum Linn.) Supplementation on Metabolic Parameters and Liver Enzymes in Young Overweight and Obese Subjects. Indian J Clin Biochem · PMID 28811698 · DOI	Controlled trial	30 Young overweight and obese adults, India	Tulsi (Ocimum sanctum) leaf extract capsule leaf 250 mg capsule twice daily on an empty stomach 8 weeks · vs No treatment (open-label, parallel group of 14 people; 16 took tulsi)	With tulsi, triglycerides (p=0.019), LDL (p=0.001), HDL (p=0.001), VLDL (p=0.019), BMI (p=0.005), insulin (p=0.021) and insulin resistance (p=0.049) improved over 8 weeks. Against the untreated group, only the HDL improvement was reported as significant (p=0.037). Liver enzymes (SGOT, SGPT) did not change significantly in either group. p-values only; no effect sizes or confidence intervals in the abstract Methods, limits and funding Outcomes: Blood fats, body mass index, insulin and insulin resistance, liver enzymes Limitations: Pilot study of 30 people, open label, no placebo, no blinding, no calorie or diet control stated in the abstract; the review reports mild nausea in the tulsi group. Read: abstract
Saxena 2012 Efficacy of an Extract of Ocimum tenuiflorum (OciBest) in the Management of General Stress: A Double-Blind, Placebo-Controlled Study. Evid Based Complement Alternat Med · PMID 21977056 · DOI	Controlled trial	150 150 adults with general stress symptoms (79 placebo, 71 OciBest)	OciBest, a standardised Ocimum tenuiflorum extract unspecified 1200 mg of actives per day 6 weeks · vs Placebo	Forgetfulness, recent sexual problems, frequent exhaustion and recent sleep problems fell more than on placebo (P <= 0.05); total symptom score fell more than placebo (P <= 0.05). No adverse events reported. Overall improvement 1.6 times (39% more) than placebo, as reported by the authors Methods, limits and funding Outcomes: Self-rated stress symptom scores at weeks 0, 2, 4 and 6 Limitations: Abstract only. Self-rated symptom scale; the plant part and extract strength are not stated in the abstract; the trial reported no adverse events. Authors' affiliation with the extract maker not checked. Read: abstract
Sethi 2010 Effect of tulsi (Ocimum Sanctum Linn.) on sperm count and reproductive hormones in male albino rabbits. International journal of Ayurveda research · PMID 21455446 · DOI	Animal research animal	Male albino rabbits	Fresh Ocimum sanctum leaves leaf 2 g of fresh leaves per rabbit a day 30 days · vs Normal diet	Sperm count fell significantly. Testosterone rose markedly; FSH and LH fell. The authors suggest a possible use as a male contraceptive. Sperm count decreased; testosterone increased; FSH and LH decreased (Not given) Methods, limits and funding Outcomes: Sperm count, testosterone, FSH, LH Limitations: Rabbits; sample size not in abstract; effect on actual fertility (pregnancies) not measured; the same paper is indexed twice in PubMed (see also PMID 21897650). Read: abstract
Sharma 1983 Sharma 1983 (as tabulated in Jamshidi & Cohen 2017) Reported in Jamshidi & Cohen 2017 table · Source	Clinical trial	20 Adults with asthma	Tulsi aqueous leaf tablets leaf 500 mg three times a day 1 week	The review table says relief within 3 days and improved vital capacity. Improvement; no comparison group Methods, limits and funding Outcomes: Asthma symptoms and vital capacity Limitations: Known only from the one-line summary in the Jamshidi and Cohen 2017 review table; the original paper was not located in PubMed or read for this profile, so details may be incomplete. Read: summary-only
Sharma 2019 Efficacy of chlorhexidine, hydrogen peroxide and tulsi extract mouthwash in reducing halitosis using spectrophotometric analysis: A randomized controlled trial. J Clin Exp Dent · PMID 31275519 · DOI	Controlled trial	45 Adults aged 17 to 35 with bad breath, India	Tulsi extract mouthwash 10 ml twice daily 15 days · vs Chlorhexidine and hydrogen peroxide mouthwashes	Bad breath, plaque and gum scores fell in all three groups. Chlorhexidine and hydrogen peroxide lowered bad breath more than tulsi, and chlorhexidine lowered plaque and gum scores more than tulsi. Tulsi worked but less than chlorhexidine; numbers not in the abstract Methods, limits and funding Outcomes: Bad breath scores (smell test and volatile sulphur compounds in saliva), plaque and gum scores Limitations: Small groups (about 15 each); 15 days only; no no-rinse group. Read: abstract
Singh 1998 Comparative evaluation of antiinflammatory potential of fixed oil of different species of Ocimum and its possible mechanism of action Indian J Exp Biol · PMID 10356964	Animal research animal			Methods, limits and funding Read: abstract
Singh 2001 Effect of Ocimum sanctum fixed oil on blood pressure, blood clotting time and pentobarbitone-induced sleeping time. Journal of ethnopharmacology · PMID 11694358 · DOI	Animal research animal	Anaesthetised dogs and rats	Ocimum sanctum fixed oil (seed oil) seed (fixed oil) Not given in abstract Acute · vs Aspirin as comparison; controls	The oil lowered blood pressure in dogs (peripheral vessel widening), increased blood clotting time by a percentage comparable to aspirin (possibly through reduced platelet clumping) and lengthened pentobarbitone-induced sleeping time in rats, suggesting it may slow the liver enzymes that clear that drug. Clotting time increase comparable to aspirin (Not given) Methods, limits and funding Outcomes: Blood pressure, clotting time, pentobarbitone sleeping time Limitations: Fixed oil from the seed is not the leaf in teas or standard extracts; animals; doses not in abstract. Read: abstract
Singh 2007 Biological activities of Ocimum sanctum L. fixed oil--an overview Indian J Exp Biol · PMID 17569280	Narrative review animal			Methods, limits and funding Read: abstract
Somasundaram et al. 2012 Somasundaram 2012 (as tabulated in Jamshidi & Cohen 2017) Reported in Jamshidi & Cohen 2017 table · Source	Controlled trial	60 Adults aged 30 to 65 with type 2 diabetes	Tulsi leaf 300 mg a day plus glibenclamide 5 mg a day leaf 300 mg a day with glibenclamide 13 weeks · vs Glibenclamide 5 mg a day alone	The review table says fasting and after-meal glucose and HbA1c were lower with tulsi plus the drug. Improvement; no numbers Methods, limits and funding Outcomes: Fasting and after-meal blood sugar, HbA1c Limitations: Known only from the one-line summary in the Jamshidi and Cohen 2017 review table; the original paper was not located in PubMed or read for this profile, so details may be incomplete. Read: summary-only
Srivastava 2023 Potential of hydroethanolic leaf extract of Ocimum sanctum in ameliorating redox status and lung injury in COPD: an in vivo and in silico study. Sci Rep · PMID 36670131 · DOI	Animal research animal	Rodents exposed to cigarette smoke for 8 weeks (a model of COPD)	Ocimum sanctum leaf hydroethanolic extract leaf 200 and 400 mg/kg before each smoke exposure 8 weeks · vs Smoke-exposed animals without extract	Less lung inflammation and oxidant damage, and more antioxidant, with the extract (p<0.01). Computer docking suggested the leaf compounds eugenol and caryophyllene bind antioxidant enzymes. Animal study; no human data Methods, limits and funding Outcomes: Lung inflammation, oxidant and antioxidant levels Limitations: Animal and computer study only; not shown in people. Read: abstract
Such 2026 System-Level, Molecular and Cellular Mechanisms of Selected Plant Adaptogens-A Review Nutrients · PMID 41901106 · DOI	Narrative review n/a			Methods, limits and funding Read: abstract
Suresh 2022 The holy basil administration diminishes the NF-kB expression and protects alveolar epithelial cells from pneumonia infection through interferon gamma. Phytother Res · PMID 35233841 · DOI	Laboratory research in-vitro	Human lung cell line (A549) infected with Klebsiella pneumoniae	Holy basil (Ocimum sanctum) extract unspecified Pretreatment for 24 hours 24 hours · vs Infected cells without extract	Basil extract reduced cell death, increased bacteria-killing and lowered NF-kB while raising interferon-gamma in infected lung cells. Cell culture only Methods, limits and funding Outcomes: Cell death, bacteria killing, cytokines Limitations: Cell culture; not tested in animals or people in this paper. Read: abstract
Tuimah Alabedi 2021 Effects of Ocimum tenuiflorum on Induced Testicular Degeneration by Filgrastim in Wistar Rats. Arch Razi Inst · PMID 35355764 · DOI	Animal research animal	40 Male Wistar rats given filgrastim (a drug that damages sperm-making tissue)	Ocimum tenuiflorum unspecified 20 mg/kg a day by mouth 1 week · vs Filgrastim alone; saline	Filgrastim damaged sperm cells and testicular tissue; the tulsi group showed some protection. Animal study; no human data Methods, limits and funding Outcomes: Testis tissue and sperm-cell damage Limitations: Rats, 1 week, high chemical stress model; not human fertility data. Read: abstract
Ugbogu 2021 A review on the traditional uses, phytochemistry, and pharmacological activities of clove basil (Ocimum gratissimum L.) Heliyon · PMID 34901489 · DOI	Narrative review n/a			Methods, limits and funding Read: abstract
Vasincu 2025 The Neuroprotective Potential of Ocimum Plant Species: Seasoning the Mind with Sweet and Holy Basil. Nutrients · PMID 40944265 · DOI	Narrative review in-vitro	Review of laboratory and animal evidence on Ocimum sanctum and Ocimum basilicum in Alzheimer's-type brain changes	Ocimum extracts (various) unspecified Various Various · vs Various	Authors say the extracts raise the brain's own antioxidant enzymes and reduce beta-amyloid and tau in experiments, and that more research is needed. None (narrative) Methods, limits and funding Outcomes: Antioxidant enzymes, beta-amyloid and tau Limitations: Abstract only. Experimental evidence and covers two basil species (holy and sweet basil); not human trials. Read: abstract
Venkatesan and Sengupta 2015 Venkatesan 2015 (as tabulated in Jamshidi & Cohen 2017) Reported in Jamshidi & Cohen 2017 table · Source	Clinical trial	30 Adults with type 2 diabetes	Tulsi leaf powder leaf 2 g a day 2 weeks · vs Curry leaves vs tulsi plus curry leaves	The review table says both blood sugar measures fell significantly. Improvement; no numbers Methods, limits and funding Outcomes: Fasting and after-meal blood sugar Limitations: Known only from the one-line summary in the Jamshidi and Cohen 2017 review table; the original paper was not located in PubMed or read for this profile, so details may be incomplete. Read: summary-only
Venu Prasad 2014 Venu Prasad 2014 (as tabulated in Jamshidi & Cohen 2017) Reported in Jamshidi & Cohen 2017 table · Source	Controlled trial	30 Healthy adults aged 18 to 30	Snack bar with 0.5% tulsi ethanolic leaf extract (1000 mg tulsi in the bars eaten daily, per the review) leaf One bar twice a day 2 weeks · vs A control bar (contents not described)	The review table says physical performance improved, and fatigue and CK were lower and the rise in lactic acid was smaller. Improvement; no numbers Methods, limits and funding Outcomes: Physical performance, fatigue, creatine kinase, lactic acid Limitations: Known only from the one-line summary in the Jamshidi and Cohen 2017 review table; the original paper was not located in PubMed or read for this profile, so details may be incomplete. Read: summary-only
Vohora 1969 Antifertility screening of plants. 3. Effect of six indigenous plants on early pregnancy in albino rats. The Indian journal of medical research · PMID 5820437	Animal research animal	Albino rats	Six Indian plants including (per its title) Ocimum sanctum, tested on early pregnancy unspecified Not available Not available · vs Not available	Only the title was read; no abstract is in PubMed, so which plants had an effect is not known. Not available (Not available) Methods, limits and funding Outcomes: Early pregnancy Limitations: Result not read. Cited only to show that this early screening study exists (1969). Read: summary-only
Wightman 2023 Chronic supplementation of a multi-ingredient herbal supplement increases speed of cognitive task performance alongside changes in the urinary metabolism of dopamine and the gut microbiome in cognitively intact older adults experiencing subjective memory decline. Front Nutr · PMID 37885445 · DOI	Controlled trial	128 128 adults aged 55 to 75 with subjective memory decline	Ten-herb blend (includes Bacopa, gotu kola, turmeric, reishi, rosemary, cardamom, holy basil, green tea, seagreens) unspecified 90 days · vs Placebo	Faster performance on cognitive tasks and fewer false alarms on rapid visual information processing; deficits in memory were observed in the herbal group, which the authors say may be due to unequal randomisation before and after COVID-19. Not given in the abstract (null) Methods, limits and funding Outcomes: Cognitive tests, urine metabolome, gut microbiome Limitations: Abstract only. Holy basil is one of about ten ingredients, so nothing can be credited to it. Funded by Pukka Herbs, whose employee is an author. NCT05504668. Funding and conflicts: Funded by Pukka Herbs Ltd Read: abstract
Xia 2011 Quantitation of ursolic acid in human plasma by UPLC-MS/MS and its pharmacokinetic study J Chromatogr B · PMID 21169069 · DOI	Analytical method			Methods, limits and funding Read: abstract
Zhu 2013 A phase I pharmacokinetic study of ursolic acid nanoliposomes in healthy volunteers and patients with advanced solid tumors Int J Nanomedicine · PMID 23319864 · DOI	Pharmacokinetic	32		Methods, limits and funding Read: abstract

What we do not know yet

What the evidence supports: possibly lower stress scores and a modest fall in fasting blood sugar. Stress and sleep are low certainty; anxiety, mood, thinking and fatigue are very low.
What is uncertain: the two main stress trials (OciBest 2012, Holixer 2022) were linked to the extract makers and have not been repeated by an independent group.
Blood sugar rests mostly on small, old Indian trials; in the 24-study review only 8 had a placebo group and 7 were high quality. No newer large trial of holy basil alone for type 2 diabetes was found, and no pooled analysis.
No human data at all were found for fertility, thyroid, bleeding and clotting, or drug interactions. All of those findings are from animals or test tubes.
No trial looked for low blood sugar when holy basil is combined with diabetes medicine.
No trial of tulsi tea or plain leaf powder for stress, mood or thinking was found; the stress evidence is for branded extracts.
Human studies lasted up to 13 weeks, so long-term effects are unknown. Nothing was found on safety in children, pregnancy or breastfeeding.
Product identity is a problem: a 2024 survey found 2 of 30 'tulsi' powders were another basil species. No survey of pesticides or heavy metals in tulsi products was found.
Which compound does the work in people is unknown; all human trials used leaf or leaf extract.
Not verified: pages from NCCIH, Memorial Sloan Kettering, LiverTox and LactMed on holy basil could not be found or opened, whether an EMA herbal monograph exists is unconfirmed, and the classical Ayurvedic verses and dates were not checked at a source.
Several body-use trials are known only from the 2017 review table; their original papers were not read.
Dosage and product comparisons are not covered yet. Ask a doctor or pharmacist about amounts.

How new research is added

New studies are found by a saved PubMed search and are placed in a review queue. A person reads each one before it changes any evidence rating or safety wording. New publications never change ratings automatically.

Lab markers

What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".

Hormonal 1

↕

Cortisol

Mixed results in trials

The body's main stress hormone, measured in saliva, hair or blood.

Low certainty

Results and what it means

Why it was measured

Cortisol is used as an objective sign of the body's stress response.

Statistical vs. clinical meaning

A fall in cortisol is a lab measure, not proof that someone feels better or is healthier. The only significant result versus placebo comes from one manufacturer-linked trial.

Safety implication

Lowering cortisol is not always good; low cortisol has its own problems. See the safety file.

Study	Result	People	Product
⁵⁰	Hair cortisol lower than placebo at week 8 (p = 0.025); after a lab stress test, salivary cortisol lower than placebo (p = 0.001)	100 adults experiencing stress	Holixer Ocimum tenuiflorum extract, 125 mg twice daily, 8 weeks
⁷²	Salivary cortisol improved over time in the extract group only; the difference from placebo was not significant	Healthy adult volunteers	Ethanolic leaf extract, 300 mg a day, 30 days
⁵¹	Review of 52 trials: holy basil listed, effect on stress hormones across most plants unclear	Adults in many trials	Various plants

^{50 72 51}

Metabolic 7

▼

Fasting blood glucose

Lowered in trials

Blood sugar after not eating for several hours.

Low certainty

Results and what it means

Why it was measured

Used to track diabetes and prediabetes.

Statistical vs. clinical meaning

A drop of about 21 mg/dl is a modest change; the trials are small and short.

Safety implication

Combined with diabetes medicine could push sugar too low; ask a clinician.

Study	Result	People	Product
²	Fell 21.0 mg/dl (17.6%) more than with placebo (CI -31.4 to -11.2, p<0.001)	Adults with type 2 diabetes (n=40)	Holy basil leaves vs placebo leaves, about 5 weeks
²⁸	Fasting sugar fell significantly (no numbers in the review table)	Men with type 2 diabetes (n=40)	Tulsi leaf capsules 3 g a day, about 6.5 weeks
⁸⁴	Lower with tulsi plus glibenclamide (no numbers)	Adults with type 2 diabetes (n=60)	Tulsi 300 mg plus glibenclamide, 13 weeks

^{2 28 84 37}

▼

HbA1c (long-term blood sugar)

Lowered in trials

A blood test that reflects average blood sugar over about 3 months.

Very low certainty

Results and what it means

Why it was measured

The standard diabetes control measure.

Statistical vs. clinical meaning

Known only from review table lines; no values; one uncontrolled.

Safety implication

Same as above.

Study	Result	People	Product
⁸⁴	HbA1c lower with tulsi plus glibenclamide than with glibenclamide alone (no numbers)	Adults with type 2 diabetes (n=60)	Tulsi 300 mg a day plus glibenclamide, 13 weeks
⁶⁸	Glycated protein/HbA1c reported to improve (no numbers; uncontrolled)	Adults with type 2 diabetes/metabolic syndrome (n=27)	Tulsi leaf powder 1 g a day, 4 weeks

^{84 68}

▼

Triglycerides

Lowered in trials

A type of fat in the blood.

Low certainty

Results and what it means

Why it was measured

High levels are linked to heart disease risk.

Statistical vs. clinical meaning

Open-label pilot with no placebo.

Safety implication

Liver enzymes did not change in the same trial.

Study	Result	People	Product
⁷⁶	Improved within the tulsi group (p=0.019); not shown to be significantly better than the untreated group	Overweight/obese young adults (n=30)	Tulsi leaf extract 250 mg twice daily, 8 weeks

⁷⁶

▼

LDL cholesterol

Lowered in trials

So-called bad cholesterol.

Low certainty

Results and what it means

Why it was measured

Higher LDL raises heart disease risk.

Statistical vs. clinical meaning

One small open-label pilot.

Safety implication

None noted.

Study	Result	People	Product
⁷⁶	Improved within the tulsi group (p=0.001); not significantly better than control in the abstract	Overweight/obese young adults (n=30)	Tulsi leaf extract 250 mg twice daily, 8 weeks

⁷⁶

▲

HDL cholesterol

Raised in trials

So-called good cholesterol.

Low certainty

Results and what it means

Why it was measured

Higher HDL is associated with lower heart risk.

Statistical vs. clinical meaning

The one lipid change that beat the control group; single pilot.

Safety implication

None noted.

Study	Result	People	Product
⁷⁶	Improved within the tulsi group (p=0.001) and more than in the untreated group (p=0.037)	Overweight/obese young adults (n=30)	Tulsi leaf extract 250 mg twice daily, 8 weeks

⁷⁶

↕

Total cholesterol

Mixed results in trials

All cholesterol in the blood.

Very low certainty

Results and what it means

Why it was measured

A broad heart disease risk marker.

Statistical vs. clinical meaning

Inconsistent and small.

Safety implication

None noted.

Study	Result	People	Product
²	Mild reduction during the holy basil period	Adults with type 2 diabetes (n=40)	Holy basil leaves vs placebo leaves
³⁷	The review's table says total cholesterol was the one lipid not improved in the Satapathy obesity trial	Overweight adults	Tulsi leaf capsules

^{2 37}

▼

Insulin and insulin resistance

Lowered in trials

How much insulin the body makes and how well it responds to it.

Very low certainty

Results and what it means

Why it was measured

High insulin and resistance come before type 2 diabetes.

Statistical vs. clinical meaning

Barely significant; no placebo.

Safety implication

None noted.

Study	Result	People	Product
⁷⁶	Plasma insulin (p=0.021) and insulin resistance (p=0.049) improved in the tulsi group	Overweight/obese young adults (n=30)	Tulsi leaf extract 250 mg twice daily, 8 weeks

⁷⁶

Organ function 1

●

Liver enzymes (SGPT/ALT and SGOT/AST)

No clear change in trials

Blood markers that rise with liver damage.

Low certainty

Results and what it means

Why it was measured

A safety check, not a benefit.

Statistical vs. clinical meaning

One 8-week pilot; safety marker only.

Safety implication

No liver signal in that trial; see the safety file.

Study	Result	People	Product
⁷⁶	No significant change in either group (SGOT p=0.141, SGPT p=0.074 in the tulsi group)	Overweight/obese young adults (n=30)	Tulsi leaf extract 250 mg twice daily, 8 weeks

⁷⁶

Other 14

▼

Perceived Stress Scale (PSS)

Lowered in trials

A short questionnaire where people rate how stressed they felt over the past month. Lower scores mean less stress.

Low certainty

Results and what it means

Why it was measured

The most common self-report way to measure stress in trials.

Statistical vs. clinical meaning

A questionnaire change is a feeling, not an objective measure. Only one trial tested holy basil alone.

Safety implication

None.

Study	Result	People	Product
⁵⁰	Greater PSS improvement than placebo (p = 0.003)	100 adults experiencing stress	Holixer extract, 125 mg twice daily, 8 weeks
⁵³	PSS lower than placebo at day 60 (p < 0.0001)	186 adults with high stress	Three-herb formula (Rhodiola, holy basil, Schisandra), 60 days; holy basil cannot be credited alone

^{50 53}

▼

Stress symptom rating scale

Lowered in trials

A self-rated list of stress-related symptoms such as forgetfulness, exhaustion and sleep problems, scored at several visits.

Low certainty

Results and what it means

Why it was measured

Used in the OciBest trial to track general stress symptoms.

Statistical vs. clinical meaning

Self-rated, not a validated clinical scale as named in the abstract; one trial.

Safety implication

None.

Study	Result	People	Product
⁷⁷	Total symptom score fell more than on placebo (P <= 0.05); about 39% more improvement than placebo	150 adults with general stress	OciBest, 1200 mg of actives per day, 6 weeks

⁷⁷

↕

Anxiety rating scales

Mixed results in trials

Questionnaires on which people (or clinicians) score anxiety. Lower scores mean less anxiety.

Very low certainty

Results and what it means

Why it was measured

Used to judge whether a treatment lowers anxiety.

Statistical vs. clinical meaning

The only improvement was in an uncontrolled study; the placebo-controlled study did not show a difference.

Safety implication

None.

Study	Result	People	Product
¹⁴	Anxiety, stress and depression ratings fell (p<0.001) from day 0 to day 60; no comparison group described	35 people with generalized anxiety disorder	Leaf extract 500 mg twice daily, 60 days
⁷²	State-Trait Anxiety Inventory improved over time in the extract group only; not significantly different from placebo	Healthy adult volunteers	Ethanolic leaf extract 300 mg a day, 30 days

^{14 72}

▼

Athens Insomnia Scale (AIS)

Lowered in trials

A questionnaire scoring insomnia symptoms. Lower scores mean better sleep.

Low certainty

Results and what it means

Why it was measured

Used to track self-rated sleep problems.

Statistical vs. clinical meaning

Self-rated, one trial, secondary outcome; authors say objective sleep measures are needed.

Safety implication

None.

Study	Result	People	Product
⁵⁰	Greater improvement than placebo (p = 0.025)	100 adults experiencing stress	Holixer extract, 125 mg twice daily, 8 weeks

⁵⁰

▼

Attention and memory test speed (Sternberg, Stroop) and P300 latency

Lowered in trials

Computer tests of memory and attention reaction time and error rate. P300 latency is how fast the brain responds to a signal, measured with electrodes on the scalp.

Very low certainty

Results and what it means

Why it was measured

Used to look for a measurable effect on thinking speed in healthy volunteers.

Statistical vs. clinical meaning

One small trial in healthy people; faster test scores do not show a real-life memory benefit. Lower values mean faster reaction.

Safety implication

None.

Study	Result	People	Product
⁷²	Reaction time and error rate improved more than placebo on Sternberg and Stroop tasks; P300 latency significantly better than placebo	Healthy adult volunteers	Ethanolic leaf extract, 300 mg a day, 30 days

⁷²

▼

After-meal (postprandial) blood glucose

Lowered in trials

Blood sugar measured after a meal.

Low certainty

Results and what it means

Why it was measured

Shows how well the body handles carbohydrate.

Statistical vs. clinical meaning

Smaller drop than fasting glucose; small trials.

Safety implication

Same caution as fasting glucose.

Study	Result	People	Product
²	Fell 15.8 mg/dl (7.3%) more than with placebo (CI -27.0 to -5.6, p<0.02)	Adults with type 2 diabetes (n=40)	Holy basil leaves vs placebo leaves
⁹¹	Reported significantly lower (no numbers)	Adults with type 2 diabetes (n=30)	Tulsi leaf powder 2 g a day, 2 weeks

^{2 91 37}

↕

Blood pressure

Mixed results in trials

The pressure of blood on artery walls.

Very low certainty

Results and what it means

Why it was measured

High pressure raises risk of stroke and heart disease.

Statistical vs. clinical meaning

No mmHg values; old and tiny trials.

Safety implication

Possible additive effect with blood pressure drugs; low blood pressure people should be cautious.

Study	Result	People	Product
⁷⁵	Fell significantly with tulsi juice in two small trials (about 25% in the second)	Adults with hypertension (n=36 across two trials)	Fresh juice about 75% tulsi, 30 mL once or twice a day, 10 to 12 days
²⁵	Improved (no numbers)	Adults with metabolic syndrome (n=100)	Aqueous tulsi leaf, 12 weeks
¹²	Changed significantly in women with low blood pressure (direction not stated)	Women with hypotension (n=50)	Juice of 15 tulsi leaves twice daily, 4 weeks

^{75 25 12}

▲

Interferon-gamma

Raised in trials

An immune signal made by T-helper cells (Th1).

Low certainty

Results and what it means

Why it was measured

Used to see whether immune cells are more active.

Statistical vs. clinical meaning

Lab marker; no infection outcomes.

Safety implication

Immune stimulation may not suit autoimmune disease.

Study	Result	People	Product
⁵⁵	Higher than placebo after 4 weeks (p=0.039)	22 healthy adults	Tulsi ethanolic leaf extract 300 mg a day, crossover

⁵⁵

▲

Interleukin-4

Raised in trials

An immune signal made by T-helper 2 cells.

Low certainty

Results and what it means

Why it was measured

Used to see whether immune cells are more active.

Statistical vs. clinical meaning

Lab marker; no infection outcomes.

Safety implication

As above.

Study	Result	People	Product
⁵⁵	Higher than placebo after 4 weeks (p=0.001)	22 healthy adults	Tulsi ethanolic leaf extract 300 mg a day, crossover

⁵⁵

▲

Natural killer (NK) cells

Raised in trials

Immune cells that attack infected and abnormal cells.

Low certainty

Results and what it means

Why it was measured

A measure of the body's early defence.

Statistical vs. clinical meaning

Lab marker; mixed-herb in one study.

Safety implication

As above.

Study	Result	People	Product
⁵⁵	Share of NK cells higher than placebo after 4 weeks (p=0.017); T-helper cells also higher (p=0.001)	22 healthy adults	Tulsi ethanolic leaf extract 300 mg a day, crossover
¹³	NK cell activity higher with a five-herb tea including tulsi	Adults 55+ with low NK activity (n=32 and 110)	Fortified tea vs regular tea

^{55 13}

▼

Dental plaque index

Lowered in trials

A score of how much plaque is on teeth.

Low certainty

Results and what it means

Why it was measured

Plaque causes gum disease and decay.

Statistical vs. clinical meaning

Short trials; scores, not tooth loss.

Safety implication

None noted.

Study	Result	People	Product
⁶⁵	Lowered by tulsi mouthwash like chlorhexidine at 30 days	Adults with gingivitis (n=60)	Tulsi mouthwash twice daily for 1 month
⁶⁰	Fell more with 4% tulsi toothpaste than placebo toothpaste (P=0.01)	Schoolchildren (n=84)	4% tulsi toothpaste, 21 days
⁸⁰	Fell with tulsi but less than chlorhexidine	Adults (n=45)	Tulsi mouthwash 10 ml twice daily, 15 days

^{65 60 80 40}

▼

Gum (gingival) inflammation index

Lowered in trials

A score of gum redness and swelling.

Low certainty

Results and what it means

Why it was measured

Shows gum inflammation.

Statistical vs. clinical meaning

Mixed between trials.

Safety implication

None noted.

Study	Result	People	Product
⁶⁵	Lowered about the same as chlorhexidine at 30 days	Adults with gingivitis (n=60)	Tulsi mouthwash twice daily
²⁴	No significant change in gingival index with tulsi gel vs chlorhexidine gel	Adults with gingivitis (n=30)	2% tulsi gel, 1 month

^{65 24 60}

▼

Salivary Streptococcus mutans

Lowered in trials

A cavity-causing mouth germ counted in saliva.

Low certainty

Results and what it means

Why it was measured

Shows effect of rinses on decay-causing bacteria.

Statistical vs. clinical meaning

A germ count, not cavities.

Safety implication

None noted.

Study	Result	People	Product
¹	Lowered, similar to chlorhexidine and Listerine	Schoolchildren (n=45)	4% tulsi rinse, 8-day phases
⁵⁴	Lowered more than fluoride rinse at 1 hour	High caries-risk patients (n=60)	4% tulsi rinse, 7 days
³⁶	Lowered in all groups including tulsi	Dental students (n=80)	Tulsi rinse twice daily, 2 weeks

^{1 54 36}

▼

Serum uric acid

Lowered in trials

A waste product that builds up in gout.

Very low certainty

Results and what it means

Why it was measured

High levels cause gout.

Statistical vs. clinical meaning

Known from a review table only.

Safety implication

None noted.

Study	Result	People	Product
⁵	Fell significantly with tulsi tincture compared with a wild rosemary tincture (no numbers)	Adults with gouty arthritis (n=200)	Tulsi tincture 10 drops three times a day, 12 weeks

⁵

Safety

What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.

Main points to know 8

In human trials holy basil looks well tolerated, but the trials are short and small. A review of 24 human studies (1,111 people, 2 to 13 weeks) found that 15 reported no adverse events, 8 did not describe any, and only one reported occasional mild nausea. In an 8-week placebo-controlled trial of 100 stressed adults taking 250 mg a day of a standardised leaf extract, no serious adverse events occurred and mild effects were about equally common on extract and placebo (12 versus 10 events). The longest human study was 13 weeks, many were small, so rare or long-term problems cannot be ruled out. Systematic review ^{37 50 77}
Pregnancy and trying to conceive: avoid it, based on animal findings and no human safety data. In rats, holy basil leaf extract and its main compound eugenol changed female hormones and were reported to reduce ovulation and impair fertility; early tests in rats from the 1960s and 1970s were titled as antifertility or early-pregnancy studies (only their titles could be read). No human pregnancy-outcome study was found. This is a precaution built on animal studies and the lack of human data, not proof that holy basil harms a pregnancy. Tea in cooking amounts is a different thing from capsules and concentrated extracts, but no source separates the two. Animal research ^{66 93 41 44}
Men trying to have a child: animal studies show lower sperm counts that came back to normal. In male rats a benzene leaf extract at 250 mg/kg for 48 days lowered sperm count and movement, and everything returned to normal 2 weeks after stopping. In rabbits fed 2 g of fresh leaves a day for 30 days, sperm count fell and testosterone rose. No study of sperm or fertility in men was found, and one rat study with a low dose of a different preparation found the opposite (it protected testes from a damaging drug). Men trying to father a child may want to avoid concentrated products until human data exist. Animal research ^{6 78 88}
It can lower blood sugar: people on diabetes medicines should talk to their prescriber. In a 1996 single-blind crossover trial in type 2 diabetes, holy basil leaves lowered fasting blood glucose by 21.0 mg/dl and after-meal glucose by 15.8 mg/dl compared with placebo. The 2017 review also describes a 12-week trial in which a leaf extract added to glibenclamide lowered glucose and HbA1c more than the drug alone (not individually read). Neither source we read reports low blood sugar episodes, but they were not designed to look for them. If you take insulin or glucose-lowering tablets, check your sugars more often and tell your prescriber. Controlled trial ^{2 37}
Possible effect on blood clotting: unproven in people. A fixed (seed) oil from Ocimum sanctum raised clotting time in dogs by about as much as aspirin, and a leaf extract reduced human platelet clumping in the test tube. Eugenol, one of its main compounds, reduced platelet clumping in test tubes and in mice without lengthening mouse bleeding time. No trial or case report of bleeding in people taking holy basil was found. If you take warfarin, aspirin, clopidogrel or a blood thinner, or have surgery planned, tell your doctor before using concentrated holy basil. Pharmacological theory ^{82 52 35 18}
Thyroid: a mouse study found lower T4; no human thyroid data. In male mice, 0.5 g/kg of leaf extract for 15 days lowered thyroxine (T4) without changing T3 and the authors called it antithyroidic. No study of thyroid function in people taking holy basil was found. If you have a thyroid condition or take thyroid medicine, ask your prescriber before using it. Animal research ⁶⁴
No liver injury reports were found, and liver tests did not change in one small trial. We found no case report of liver injury from holy basil, and no LiverTox entry for it. In an 8-week open-label trial of 16 overweight adults taking 250 mg of leaf extract twice daily, liver enzymes SGOT and SGPT did not change significantly. Animal studies at up to 1,000 mg/kg for 28 days showed no liver changes. Not finding cases does not prove none occur; liver injury from herbs is often missed or unreported. Controlled trial ^{76 69 29 62}
What you are buying may not be the right plant. DNA tests found that some products and plants sold as tulsi are another Ocimum species: 2 of 30 Indian market powders (6.5%) were O. gratissimum, and a UK study found possible O. gratissimum substitution in household plants and could not authenticate many commercial products. A 2014 review also says European tulsi products have shown frequent substitution with other herbs, including sweet basil (secondary citation, not checked at source). Purple tulsi, which was most of the Indian samples, is described by the authors as higher in methyl eugenol. Other ^{10 11 21}

Side effects 13

Effect	How often	Severity and recovery	Evidence
Digestive disturbances (stomach upset, nausea) The 2017 review says one trial of leaf extract capsules before meals (250 mg twice daily, 16 obese adults) reported occasional nausea. In the 2022 trial one participant on placebo withdrew because of nausea.	5 events on holy basil and 5 on placebo (about 100 adults, 250 mg/day for 8 weeks)	mild Reversible	Controlled trial ^{50 37}
Headache Same 8-week trial; the difference is within chance.	3 on holy basil vs 2 on placebo	mild Reversible	Controlled trial ⁵⁰
Agitation A single case; cannot be called a drug effect.	1 on holy basil vs 0 on placebo (the person withdrew)	mild Resolved after withdrawal, as presumed	Controlled trial ⁵⁰
Skin rash Equal in both groups.	1 on holy basil vs 1 on placebo	mild Not described	Controlled trial ⁵⁰
Vivid dreams Equal in both groups.	1 vs 1	mild Not described	Controlled trial ⁵⁰
Reduced libido A single report. Separately, rabbit data show lower sperm count and higher testosterone; no human libido study was found.	1 on holy basil vs 0 on placebo	mild Not described	Controlled trial ^{50 78}
Sleep disturbance Occurred on placebo only.	0 on holy basil vs 1 on placebo	mild Not described	Controlled trial ⁵⁰
Low blood sugar (hypoglycemia) when combined with diabetes drugs A theoretical risk from glucose lowering of about 21 mg/dl fasting in type 2 diabetes. The trials did not report looking for it.	No hypoglycemia events were reported in the sources we read; frequency unknown	moderate Not applicable	Controlled trial ^{2 37}
Longer blood clotting time or easier bruising and bleeding Based on an oil in dogs, a leaf extract on human platelets in the test tube and eugenol in the test tube and in mice. Mouse bleeding time was not prolonged by eugenol.	Not reported in any human study found	moderate Not applicable	Pharmacological theory ^{82 52 35}
Low blood pressure or dizziness A fixed oil lowered blood pressure in anaesthetised dogs. The 2017 review describes small human trials where blood pressure fell in hypertensive people and was normalised in people with low blood pressure; the individual studies were not read.	Not reported in the human safety data read	moderate Not applicable	Pharmacological theory ^{82 37}
Lower sperm count and fertility (men) or changed cycle hormones (women) No human fertility study was found. See pregnancy and fertility notes.	Animal studies only; no rate in humans	moderate In the rat study, sperm values recovered 2 weeks after stopping	Animal research ^{6 78 66}
Lower thyroxine (T4) No human thyroid study found.	Mouse study only	moderate Not tested	Animal research ⁶⁴
Raised liver enzymes or liver injury No case reports found. The absence of reports is not proof of safety.	None reported; liver enzymes unchanged in 16 treated adults (8 weeks)	serious Not applicable	Controlled trial ^{76 62}

Liver

We found no published case of liver injury from holy basil (Ocimum tenuiflorum or O. sanctum) and no LiverTox entry for it. In one small open-label trial (16 overweight adults, 250 mg leaf extract twice daily for 8 weeks), SGOT and SGPT did not change significantly. In rats, extracts up to 1,000 mg/kg a day for 28 days caused no changes in liver tests or tissue, and in other rat studies the extract lowered liver enzyme rises caused by toxic chemicals. Those animal findings suggest it does not harm the liver at the tested doses but are not proof for people. ^{76 69 29 52 62}

How often. No frequency of human liver injury exists. No reports were found, which is not proof that none occur. Herb liver injuries are often missed unless a product is named.

Monitoring. No agency monitoring advice was found. If you notice yellow skin or eyes, dark urine, pale stools or severe itching, stop the product and seek care.

This is a safety connection. It is not evidence that Holy Basil (Tulsi) supports liver health.

Medicines and supplements 10

With	Why it matters	Importance	Evidence	What to do
Diabetes medicines (insulin, metformin, glibenclamide and others) prescription	Holy basil lowered fasting glucose by 21.0 mg/dl and after-meal glucose by 15.8 mg/dl in people with type 2 diabetes. Combined with glucose-lowering drugs the effect could add up.	The 2017 review describes a 12-week trial in which 300 mg of leaf extract with glibenclamide lowered glucose and HbA1c more than the drug alone (not individually read). No hypoglycemia events were reported in the sources read, but they were not looked for specifically.	Controlled trial Low certainty ^{2 37}	Tell your prescriber. Check blood sugar more often at the start, and know the signs of low blood sugar (sweating, shakiness, hunger, confusion).
Blood thinners and antiplatelet drugs (warfarin, apixaban, clopidogrel, aspirin) and NSAIDs prescription	Fixed oil lengthened clotting time in dogs by about as much as aspirin; a leaf extract and eugenol reduced human platelet clumping in the test tube. Eugenol did not lengthen bleeding time in mice.	Theory and lab only. No human bleeding report or trial was found.	Pharmacological theory Very low certainty ^{82 52 35 18 43}	Do not combine without telling your prescriber; ask whether extra clotting tests are needed if you take warfarin.
Thyroid medicines (levothyroxine) and anti-thyroid drugs prescription	Leaf extract lowered T4 in mice. In people, the effect is unknown.	Animal only.	Animal research Very low certainty ⁶⁴	Ask your prescriber before using it, and ask for thyroid tests if you start.
Seizure medicines (valproate, levetiracetam) prescription	In rats, a leaf extract did not significantly change valproate blood levels; with levetiracetam the only change was a later peak time.	Rats given 1,000 mg/kg showed no important interaction, and the extract itself had some anticonvulsant effect. This does not tell us what happens in people.	Animal research Very low certainty ^{73 74}	Tell your neurologist; do not stop or change epilepsy medicine because of holy basil.
Sedatives, sleeping pills and alcohol prescription	A fixed oil lengthened pentobarbitone sleeping time in rats, which the authors link to slower breakdown in the liver.	Animal only and for a seed oil; no human sedation reports were found in the trials read.	Animal research Very low certainty ⁸²	Be cautious combining with sedatives until you know how you react.
Drugs cleared by liver CYP enzymes and drug pumps (many medicines) prescription	A five-herb mixture containing Ocimum sanctum raised phase II enzymes and lowered the intestinal drug pump P-glycoprotein in rats. Tulsi alone was not tested.	Rat data on a mixture; cannot be assigned to tulsi. No human CYP data were found.	Animal research Very low certainty ^{48 49}	Treat medicines with a narrow safe range (for example transplant or heart medicines) with extra caution and ask a pharmacist.
Antibiotics (ceftriaxone) prescription	In goats, raw leaf juice (5 ml/kg) raised ceftriaxone levels and slowed its removal.	Single animal study with very large juice doses.	Animal research Very low certainty ²²	No human advice is possible from one goat study; mention holy basil to your doctor when you take antibiotics.
Blood pressure medicines prescription	A fixed oil lowered blood pressure in dogs; the review describes human blood pressure changes in small studies.	Blood-pressure effects in people are unclear and the studies were not read individually.	Pharmacological theory Very low certainty ^{82 37}	Check your blood pressure if you add it to medicines for blood pressure.
Immune-suppressing medicines (after transplant or for autoimmune disease) prescription	In 22 healthy volunteers 300 mg a day of leaf extract for 4 weeks raised interferon-gamma, IL-4, T-helper cells and NK cells.	Unknown meaning for people on immune drugs; theory only.	Controlled trial Very low certainty ⁵⁵	Ask your specialist before using it if you take immune-suppressing medicine.
Fertility treatment, contraceptives and hormone medicines prescription	Extract and eugenol changed estradiol and progesterone in rats; extracts changed sperm values in male rats and rabbits.	Animal only.	Animal research Very low certainty ^{66 6 78}	Avoid while trying to conceive or on fertility treatment unless your doctor agrees.

Who should check first 11

Situation	Advice	Evidence
Pregnancy	Avoid concentrated products. No human safety data; animal studies suggest hormone and fertility effects. A precaution, not proof of harm.	Animal research ^{66 93 41}
Breastfeeding	Avoid concentrated products. We found no information on holy basil in breast milk; no LactMed entry was found.	Authoritative guidance ¹⁹
Trying to conceive (both partners)	Avoid concentrated products until human data exist. Rat and rabbit studies show lower sperm counts and altered hormones.	Animal research ^{6 78 66}
Children and teenagers	No safety guidance for children was found. The 2017 review included participants aged 10 to 80, but the child data were not examined. Ask a paediatrician.	Systematic review ³⁷
Diabetes treated with insulin or tablets	Use only with your prescriber's knowledge; check blood sugar.	Controlled trial ^{2 37}
Bleeding disorders or blood-thinning medicines	Avoid concentrated products unless your doctor agrees. Theory-based.	Pharmacological theory ^{82 52}
Planned surgery	No holy-basil-specific guidance was found. Because of the theoretical effects on clotting and blood sugar, tell your surgical team about any supplement and ask whether to pause it beforehand.	Pharmacological theory ^{82 35}
Thyroid disease	Ask your prescriber first. Mouse data show lower T4.	Animal research ⁶⁴
Low blood pressure	Be cautious; blood pressure effects are possible.	Pharmacological theory ⁸²
Liver disease	No data. As with any herb, discuss with your doctor.	Authoritative guidance ⁶²
Allergy to basil or other Lamiaceae (mint family) plants	Avoid. We found no allergy case report for holy basil; this is a general precaution.	Pharmacological theory

Overdose, product quality and regulators

Summary. In animal tests, holy basil leaf extracts show low toxicity: no deaths at 5 g/kg in a single dose and no organ damage in 28-day tests up to 1,000 mg/kg. Repeated-dose testing beyond 28 days and reproduction and cancer testing of tulsi were not found, and there are no human overdose data.

Animal. OciBest extract at 5 g/kg in rats: no treatment-related toxic effects over 14 days, and it was not mutagenic or chromosome-damaging in the standard tests. Holixer extract: non-mutagenic and non-clastogenic, and no acute toxicity up to 5 g/kg in rats. A methanolic/aqueous extract at 250, 500 and 1,000 mg/kg for 28 days in rats: no toxic changes except slightly higher mean corpuscular haemoglobin at 1,000 mg/kg. A 50% ethanol extract at 200 to 800 mg/kg for 28 days in rats and up to 2,000 mg/kg once in mice: no toxic signs. The essential oil had a mouse LD50 of 4,571.43 microlitres per kg.

Human doses studied. The 2017 review lists 300 mg to 3,000 mg a day of leaf extract, 300 to 1,000 mg once or twice daily of ethanolic extract, 6 to 14 g a day of whole-plant aqueous extract and 10 g of fresh leaf, for 2 to 13 weeks. The 2022 trial used 250 mg a day for 8 weeks; the 2012 trial used 1,200 mg of actives a day for 6 weeks.

High dose or long term signals. No human high-dose or long-term (over 13 weeks) data were found. In animals, hormone and sperm effects and lower T4 were reported at doses well above supplement doses per kg.

Overdose response. No human overdose case was found.

Genotoxicity. Two commercial extracts were not mutagenic or chromosome-damaging in standard tests. Methyl eugenol, which is higher in purple tulsi according to one author group, is described by them as potentially carcinogenic; no measurements or human risk numbers were read. The effect of normal tea or supplement intake on cancer risk has not been studied.

Toxic plant parts. No toxic plant part was identified in the sources read. Essential oil is concentrated eugenol-rich oil and should not be swallowed undiluted; the LD50 is for mice and not a safe dose for people. Eugenol content of tulsi was not quantified here. The concern for consumers is substitution with O. gratissimum or other plants rather than a poisonous part of tulsi itself.

Product identity is the documented quality problem: DNA tests found other Ocimum species sold or grown as tulsi. We found no survey of pesticide or heavy-metal residues in tulsi supplements, so quality is unknown rather than known to be good.

Wrong species (Ocimum gratissimum). 2 of 30 Indian market tulsi powders (6.5%) were O. gratissimum, not O. tenuiflorum. A UK study found possible substitution of O. gratissimum in plants shared in South Asian households. ^{10 11}

Commercial products hard to authenticate. In a UK DNA barcoding study 47 commercial samples were difficult to authenticate, probably because manufacturing degraded the DNA. This means labels cannot be confirmed from the DNA alone. ¹¹

Purple vs green tulsi (methyl eugenol). 80% of 30 Indian market powders were purple tulsi, which the authors say contains more methyl eugenol, a compound they describe as moderately toxic and potentially carcinogenic. A methyl-eugenol-rich chemotype of O. tenuiflorum has been described. How much methyl eugenol is in typical products, and whether it matters at normal intake, was not shown. ^{10 46 39}

Sweet basil substitution. A 2014 review says European tulsi products had frequent substitution with other herbs including Ocimum basilicum. The original 2009 paper was not read. ²¹

Heavy metals in polluted soils. The same review says leaves from polluted areas had nearly twice the toxic-element levels of leaves from unpolluted areas, citing a 2003 Indian paper that we could not verify. No survey of retail products was found. ²¹

Body	Action	Date

When to get medical help

Trouble breathing, swelling of the face or throat, or a widespread rash soon after taking holy basil: call emergency services (possible allergy).
Yellow skin or eyes, dark urine, pale stools or severe itching: stop it and get medical care the same day (liver warning signs; none are documented for holy basil, but any herb can rarely cause them).
Shakiness, sweating, confusion or fainting if you take diabetes medicine: check your blood sugar and treat low sugar; call for help if you cannot recover.
Unusual bruising, nosebleeds, blood in urine or stool, or heavy bleeding while on blood thinners: seek medical care promptly and stop the product.
Pregnancy, or vaginal bleeding or cramps while using a concentrated product: stop it and contact your doctor.
Fast heartbeat, tremor or heat intolerance if you have a thyroid condition: see a doctor (thyroid effects are untested in people).

Stop the supplement and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.

General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.

Frequently asked questions

Does holy basil help with stress?

It may help a little, but the confidence is low. Two placebo-controlled trials of branded extracts (OciBest in 150 adults for 6 weeks, Holixer in 100 adults for 8 weeks) found lower stress scores than placebo, and the newer one also found lower hair cortisol. Both were funded by or linked to the extract makers, and no independent group has repeated them. Sleep looked a little better in the same trials (low certainty).

^{77 50 72 51}

Does holy basil help with anxiety?

There is no good evidence yet. The only anxiety study in patients was small (35 people with generalized anxiety disorder), ran for 60 days and had no placebo group, so it cannot show the herb caused the improvement. The stress trials give only indirect hints. Certainty is very low. Anxiety that is affecting daily life deserves a proper check-up.

^{14 72 53}

Does holy basil lower blood sugar?

It is the one effect with a real human signal, but the certainty is low. In a 1996 single-blind crossover trial in people with type 2 diabetes, holy basil leaves lowered fasting blood glucose by about 21 mg/dl compared with placebo. A review of 24 human studies (most from India, many old) found good results, but only 8 of the 24 had a placebo group and only 7 were high quality. It is not a replacement for diabetes medicine.

^{2 37}

Does holy basil lower cholesterol?

Maybe a little, but the evidence is low certainty. A handful of small trials report better triglycerides, LDL and HDL. In the one trial we could read (30 overweight young adults, 8 weeks), all three improved compared with the start, but only HDL was clearly better than the untreated group.

^{76 37}

Does holy basil affect fertility or pregnancy?

Nobody knows for people. No human study has looked at fertility, sperm or pregnancy outcomes with holy basil. In rats and rabbits, extracts changed hormones, lowered sperm counts (which recovered after stopping in one rat study) and reduced ovulation. Animal results do not prove harm in people, but they are the reason to avoid concentrated products while trying to conceive.

^{66 6 78 88}

Does holy basil affect the thyroid?

No human thyroid data were found. In male mice, a leaf extract lowered the thyroid hormone T4 (0.5 g/kg for 15 days). If you have a thyroid condition or take thyroid medicine, ask your prescriber before using concentrated holy basil.

^{64 63}

Can I take holy basil with diabetes medicine?

Only with your prescriber's knowledge. Holy basil lowered blood sugar in trials, so with insulin or glucose-lowering tablets the effects could add up and cause low blood sugar. The sources we read did not report low-sugar episodes, but they were not designed to look for them. Check your sugars more often when you start, and know the signs: sweating, shakiness, hunger and confusion.

^{2 37}

Is holy basil safe in pregnancy or while breastfeeding?

Not enough is known, so avoid concentrated products. There is no human pregnancy or breast-milk safety information. Rat studies found hormone and fertility effects, which is a precaution and not proof of harm. Tea in food-like amounts is a different thing from capsules and extracts, but no source separates the two. Ask your doctor.

^{66 93 41 19}

What about tulsi tea?

Tea is how tulsi is traditionally taken, but the stress trials used branded extracts and no trial of tea or plain leaf powder for stress, mood or thinking was found. So the trial results cannot be assumed for tea. The one tea study found was in people having radioactive iodine treatment, and it looked at anxiety and mouth side effects. For amounts, ask a doctor or pharmacist. Check that a label names Ocimum tenuiflorum (also called Ocimum sanctum).

^{63 77 50 10}

What is the difference between holy basil and sweet basil?

They are different plants in the same genus. Holy basil or tulsi is Ocimum tenuiflorum. Sweet basil (Ocimum basilicum) is the pesto and Italian-cooking basil. The research on holy basil should not be applied to sweet basil. Mix-ups happen in the market: a 2024 survey of 30 'tulsi' powders in India found 2 were actually another basil species (Ocimum gratissimum), and a review says European tulsi products have shown substitution with other herbs, including sweet basil (that review was not checked at its original source).

^{10 11 21}

Who should avoid holy basil?

Talk to a doctor first if you are pregnant, breastfeeding or trying to conceive, take diabetes medicine, blood thinners or aspirin, thyroid medicine or immune-suppressing medicine, have a bleeding disorder, a thyroid condition or low blood pressure, or have surgery planned. Avoid it if you are allergic to basil or other mint-family plants. No safety guidance for children was found. Most of these cautions come from animal and test-tube findings, not from human cases.

^{64 82 52 2 55 37}

How long have the studies on holy basil lasted?

Not long. A review of 24 human studies (1,111 people) covered 2 to 13 weeks, and the two main stress trials ran for 6 and 8 weeks. Of the 24 studies, 15 reported no side effects, 8 did not describe any, and one reported occasional mild nausea. So it looks well tolerated in the short term, but long-term effects and rare problems are unknown.

^{37 77 50}

Editorial transparency

Written by: AlternativeMed editorial team. Research compiled with AI assistance, then checked against PubMed records.
Medical review: None. This page has not been reviewed by a physician or pharmacist.
First published: 2026-10-25
Last substantive update: 2026-10-25
How we research: We searched PubMed and Europe PMC, read the abstracts of the studies cited, and read the full text of a 2017 systematic review and a 2014 review for history and for trials known only from its table. Plant names were checked in GBIF and NCBI Taxonomy. Pages from NCCIH, Memorial Sloan Kettering, LiverTox, LactMed and the FDA on holy basil could not be found or opened, and whether an EMA herbal monograph exists was not confirmed; all are marked not verified. The classical Ayurvedic verses were not checked at a source. Certainty ratings are the compiler's own reading, not formal grades. No study is cited that we could not verify.
How we rate evidence: See "How we rate evidence" in the Evidence tab.
Independence: No product is promoted on this page. No affiliate links are shown. If one is added later it will be labelled and kept apart from the evidence.

Sources 96

Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.

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