Cannabis & Cannabinoids · Terpenes · A plant scent molecule found in tea tree, cajuput and pine oils, lilac flowers and cannabis

Terpineol

Q: What is terpineol?

Terpineol is a small plant scent molecule (a monoterpene alcohol, C10H18O). Usually the name means alpha-terpineol. Cannabis makes it, and so do tea tree, cajuput and pine oils and lilac flowers.

Q: Which terpineol do studies mean?

Most mean alpha-terpineol. Beta-terpineol and gamma-terpineol are other isomers (one cell paper in this page is about gamma-terpineol). Terpinen-4-ol, sometimes called 4-terpineol, is a different molecule that makes up a large part of tea tree oil. Industry papers also use plain 'terpineol' for a blend. Check which one a source means before comparing results.

Q: Where is terpineol found?

In tea tree oil (3.11 to 4.66% in seven oils), cajuput oil (about 8% in five batches), some pine oils (1.4 to 5.3%), lilac flowers, lemon leaf oil of one type, orange juice volatiles and cannabis. Abstracts also name Eucalyptus species. The lime oils in one study did not name it.

Q: Which cannabis strains have the most terpineol?

In our lab data, 12 named strains have a measurement, from 0.1 mg/g (Fortune Cookies) to 0.9 mg/g (Gelato), all means of 5 to 10 samples from one California dispensary in 2015 to 2016. The same strain name varies between samples, and these numbers say nothing about effects.

Q: Is there human research on terpineol?

Very little. No trial has tested alpha-terpineol on its own. One company-funded trial gave adults with insomnia a capsule with 300 mg CBD and eight terpenes including alpha-terpineol. Studies of terpinen-4-ol for eyelid mites are about a different molecule.

Q: Does terpineol help with pain?

In mice it reduced pain behaviour in several tests, including nerve-injury pain, and the effect depended in part on cannabinoid receptors. No one has tested it for pain in people, so no one knows.

Q: Does terpineol help with sleep or anxiety?

There is no evidence for alpha-terpineol itself. A CBD-plus-eight-terpene mixture slightly raised deep plus REM sleep in a company-funded trial, and the rat anxiety study's abstract names no alpha-terpineol effect.

Q: Does terpineol change how THC feels?

Unknown. In frog egg cells with human receptors, terpineol boosted THC's activation of CB1. Nobody has tested this in people, and THC's impairment, anxiety and dependence risks do not go away.

Q: Is terpineol safe?

There is not enough human data to say. The pure chemical is notified as a skin and eye irritant. Oils that contain it can cause skin allergy, especially when old. One rat study found fetal harm at large doses. Ask a doctor or pharmacist before using concentrated products.

Q: Is terpineol safe in pregnancy?

No human data exist. A 2026 rat study found lower fetal weight and skeletal malformations at 75 to 300 mg/kg. People who are pregnant or breastfeeding should ask their doctor before using essential oils, terpene products or cannabis.

2-(4-methylcyclohex-3-en-1-yl)propan-2-ol (alpha-terpineol), C10H18O · also called Terpineol, alpha-terpineol, alpha-terpinenol, p-menth-1-en-8-ol, 1-p-menthen-8-ol (beta-terpineol, gamma-terpineol and terpinen-4-ol are different molecules)

Terpineol is a small plant molecule (a monoterpene alcohol with ten carbon atoms). The name usually means alpha-terpineol, which PubChem lists as C10H18O. Cannabis makes it, and so do tea tree, cajuput and pine oils, and lilac flowers. Almost all research is in cells or animals. No trial has tested alpha-terpineol on its own in people.

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

About Terpineol

Terpineol (mostly alpha-terpineol) is a small plant scent molecule. Cannabis makes it, as do tea tree, cajuput and pine oils and lilac flowers. Almost all research is in cells and animals, and no trial has tested it on its own in people. The best-documented hazards are skin and eye irritation from the pure chemical, and one rat study found fetal harm at large doses. In our lab data it ranges from 0.1 to 0.9 mg/g in 12 named strains from one dispensary.

What it is

Terpineol is a monoterpene alcohol with the formula C10H18O. The name is used loosely. Alpha-terpineol (PubChem compound 17100; 2-(4-methylcyclohex-3-en-1-yl)propan-2-ol) is the one most studied and the one measured in cannabis. Beta-terpineol and gamma-terpineol are other isomers. Terpinen-4-ol, sometimes written 4-terpineol, is a different molecule that makes up about 38 to 44% of tea tree oil. Industry papers also use plain 'terpineol' for a blend of isomers.

Cannabis makes terpenes in the resin glands of the female flower. Validated lab methods measure alpha-terpineol as one of ten terpenes. In a study of 21 varieties it was higher in THC-dominant than in CBD-dominant ones. How the plant makes alpha-terpineol was not found in the sources read.

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Where you meet it

Tea tree oil is 3.11 to 4.66% alpha-terpineol in seven oils tested. Cajuput oil averaged 7.87% (6.53 to 9.28%) in five batches in the EFSA file. Pine oils vary: 2.8 to 5.0% in Nepali Pinus roxburghii oils and 1.4 to 5.3% in one American pine's needle oil, while two other American pines in the same study did not list it. Alpha-terpineol is listed among the most abundant scent compounds of fresh lilac flowers (Syringa oblata) with no percentage given, and one type of lemon leaf oil is described as linalool / linalyl acetate / alpha-terpineol. The lime peel and leaf oil types in that study did not name it, so we do not say limes are a source.

Two abstracts name Eucalyptus species as a source, and others name Salvia libanotica oil and the resin of Protium heptaphyllum. It is also an allowed food flavouring in the US (see Regulatory status). A terpineol percentage in a plant oil does not tell you what the oil will do; oils differ by species, place and batch.

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What the lab numbers show

Our data hold alpha-terpineol measurements for 12 named strains (76 samples in all). Three of them have a profile page here: Gelato, OG Kush and Trainwreck. All values come from one published study of samples bought from one California medical dispensary between February 2015 and February 2016 and tested at Excelsior Analytical Laboratory (Union City, California) by gas chromatography with a flame ionisation detector, with GC-MS used to confirm peaks. They are means of 5 to 10 dried-flower samples per name, reported in mg/g, and the paper does not say whether this was on a dry-weight basis. The values range from 0.1 to 0.9 mg/g. (Each value is recorded twice in our files, once as a summary and once with fuller notes; they are the same measurements and are counted once here.)

These numbers are real lab results from specific samples, not our own testing. The same strain name can have very different chemistry from sample to sample: the standard deviations printed in the paper run from 0.1 to 0.4 mg/g, and Fortune Cookies is listed as 0.1 mg/g with a standard deviation of 0.2, which shows how much a name can vary. Do not compare these mg/g values with percentages from other datasets, and do not compare them with the 0.19 to 0.75% of steam-distilled flower oil reported for two South African cultivars, which is a different measure.

Examples, all in mg/g as means of dispensary samples: highest, Gelato 0.9 (5 samples, SD 0.1), then Skywalker OG Kush and Superman OG Kush 0.7 each (6 and 7 samples); in the middle, OG Kush 0.5 (10 samples, SD 0.4), Trainwreck 0.5 (7 samples, SD 0.3) and Sherbert 0.5 (7 samples); lowest, Fortune Cookies 0.1 (5 samples, SD 0.2). The numbers measure the content of the flower. They say nothing about how a strain will feel or whether alpha-terpineol has any effect in people.

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The popular claims

"Terpineol makes cannabis sedating." No source read supports this. The only human trial that included it was a CBD-plus-eight-terpene mixture, and the rat anxiety study's abstract names no effect of alpha-terpineol. The mouse pain studies are not tests of sedation.

"Terpineol boosts THC." In frog egg cells, terpineol boosted THC's activation of CB1 more than expected, and the authors include employees of a medical cannabis maker. Nobody has shown this in people, and a stronger signal in a dish is not shown to be better or safer.

"Terpineol fights cancer or infection." It does not treat either. Dishes and mice only; the DNA damage that kills tumour cells in a dish is also a safety signal.

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What the research shows

Human: the only human trial that included alpha-terpineol gave 125 adults with insomnia 300 mg CBD plus eight terpenes at 1 mg each for 4 weeks. The share of the night in slow-wave plus REM sleep rose by 1.3% on average (95% CI 0.1 to 2.5%) and no adverse events were reported. It was funded by the maker, and the effect cannot be credited to alpha-terpineol. Trials of terpinen-4-ol (a different molecule) for eyelid mites exist: a 40-person open-label trial found fewer mites during treatment and a rebound after wipes alone were stopped.

Animals: in mice, alpha-terpineol reduced pain behaviour in formalin, writhing, glutamate, capsaicin, inflammatory and nerve-injury tests, with the nitric oxide pathway and CB1 and CB2 receptors involved. In a tumour model it reduced cancer-pain behaviour. In rats it protected against alcohol-induced stomach ulcers, delayed stomach emptying and reduced drug-induced heart damage. In asthmatic mice it reduced airway inflammation.

Cells: alpha-terpineol lowered inflammation signals in macrophages and mouth cells, killed several tumour cell types, and slowed bacteria. All of this is in dishes. The anxiety-like behaviour study in rats names no alpha-terpineol effect.

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Regulatory status

In the US, section 172.515 of the Code of Federal Regulations lists alpha-terpineol and beta-terpineol among synthetic flavouring substances and adjuvants that may be safely used in food under stated conditions (minimum quantity needed for the effect, good manufacturing practice). Gamma-terpineol is not on that list. This is a food-flavouring rule and says nothing about vaping, supplements or cannabis products. We read it through the eCFR on 2026-10-25.

In the EU, an EFSA opinion on cajuput oil (2024) lists alpha-terpineol in the EU register of flavouring substances and calls the whole oil an irritant and sensitiser. Companies' notified hazard classes for the pure chemical are skin and eye irritation. We did not read rules on cannabis or vape products, and this page gives no legal advice.

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At a glance

Traditional uses history, not proof

Flavouring ingredient in food: the US FDA lists alpha-terpineol and beta-terpineol among allowed synthetic flavourings (eCFR)
Ingredient of household disinfectants (hospital poisoning reports name Dettol, with chloroxylenol and terpineol)
Fragrance ingredient (industry safety reviews exist; the findings could not be read)
Plants that contain it have traditional uses (for example Nepali pine oil on wounds), but those are uses of the plants, not of terpineol

Studied for research

Pain: mouse studies only, very low certainty
Cancer-related pain: one mouse study, very low
Anxiety-like behaviour: one rat study that names no effect for it, insufficient
Sleep: one company-funded trial of a CBD-plus-eight-terpene mixture, insufficient for terpineol itself
Inflammation and asthma: cells and mice, very low
Cancer cells: dishes and one mouse model, very low (not a treatment)
Stomach and heart: rat studies, very low
Germ killing: lab dishes, insufficient
Terpinen-4-ol (a different molecule) for eyelid mites: kept separate, very low

Main compounds

alpha-Terpineol, C10H18O (PubChem CID 17100; R and S mirror forms CID 442501 and 443162)
beta-Terpineol (CID 8748) and gamma-terpineol (CID 11467), different isomers
Terpinen-4-ol / 4-terpineol (CID 11230), a different molecule: the main part of tea tree oil
Related cannabis terpenes: limonene, linalool, pinene, terpinolene, myrcene, beta-caryophyllene

Common forms

Natural part of cannabis flower and extracts
Component of tea tree, cajuput and pine essential oils
Pure compound in lab studies
Ingredient in flavours, fragrances and some disinfectants

Research links: PubChem: alpha-Terpineol · US eCFR: 21 CFR 172.515 (synthetic flavouring substances) · EFSA opinion on cajuput oil (PubMed) · Terpenoid chemotypes in cannabis cultivars, Fischedick 2017 (PubMed) · Terpenes in nerve-injured mice (PubMed) · Research Library · Genes & Biomarkers Library

What it is and its history

Name: Terpineol: usually alpha-terpineol (other forms are beta-terpineol, gamma-terpineol and the separate molecule terpinen-4-ol)
Chemical name: 2-(4-methylcyclohex-3-en-1-yl)propan-2-ol (alpha-terpineol)
Other names: alpha-Terpineol; p-Menth-1-en-8-ol; 1-p-Menthen-8-ol; alpha-Terpinenol; Carvomenthenol; alpha,alpha,4-Trimethyl-3-cyclohexene-1-methanol; dl-alpha-Terpineol (the form without a stated mirror image); (S)-(-)-alpha-Terpineol / L-alpha-terpineol (CID 443162)
Common names: Terpineol (English); alfa-Terpineol (Spanish)
Formula: C10H18O
Molecular weight: 154.25
CAS number: 98-55-5
PubChem ID: 17100
Chemical class: Monoterpene alcohol (monoterpenoid): a ten-carbon plant molecule with one ring and one -OH group (formula C10H18O)
How the plant makes it: Not verified here. None of the sources read describes how the cannabis plant makes alpha-terpineol. Cannabis makes terpenes in the sticky resin glands (trichomes) of the female flower, but the specific pathway for alpha-terpineol was not read.
Where it is found: Cannabis flower: alpha-terpineol is one of ten terpenes that validated lab methods measure, and in a 21-variety study it was higher in THC-dominant than in CBD-dominant varieties. In the steam-distilled flower oil of two South African cultivars it was 0.19 to 0.75% of the oil.; Tea tree oil (Melaleuca alternifolia): 3.11 to 4.66% in seven oils, next to terpinen-4-ol (37.66-44.28%).; Cajuput oil (Melaleuca cajuputi and M. leucadendra): mean 7.87% (range 6.53-9.28%) in five batches, next to 1,8-cineole (61.46%).; Pine needle, cone and bark oils: 2.8 to 5.0% in Pinus roxburghii (Nepal); 1.4 to 5.3% in P. ponderosa var. ponderosa needle oil. The needle oils of P. contorta and P. flexilis in the same study did not list it.; Lilac (Syringa oblata) flowers: listed among the most abundant scent compounds, with no percentages given.; Lemon leaf oil: one of two lemon leaf oil chemotypes was described as linalool / linalyl acetate / alpha-terpineol. The lime peel and leaf types in the same abstract did not name it.; Orange juice volatiles: found in significant amounts in the juice distillate in a cell study.; Other plants named in abstracts as sources: Eucalyptus species, Salvia libanotica essential oil, and the resin of Protium heptaphyllum.
Related or similar compounds: Name: Terpinen-4-ol (4-terpineol); Note: PubChem CID 11230, C10H18O. The main part of tea tree oil (37.66-44.28% in seven oils). It is a different molecule with its own research, including eyelid-mite trials. Writing 4-terpineol makes it easy to confuse with terpineol.; Name: Beta-terpineol and gamma-terpineol; Note: PubChem CIDs 8748 and 11467. Other isomers (same formula, different shape). The cell research on gamma-terpineol and liver cancer cells is not about alpha-terpineol.; Name: Other cannabis terpenes; Note: Limonene, linalool, pinene, terpinolene, myrcene and beta-caryophyllene are different molecules with their own pages and properties.

Traditional use and history history, not clinical proof

Tradition or era	Documented use	Source
Food flavouring ingredient	The FDA lists alpha-terpineol and beta-terpineol among synthetic flavouring substances and adjuvants that may be safely used in food under stated conditions (read 2026-10-25).	21 CFR 172.515 via eCFR
Fragrance ingredient	Alpha-terpineol and terpineol have been assessed by the fragrance industry's safety institute as fragrance ingredients (PubMed lists reviews from 2008, 2017 and 2024). The findings were not available to read.	Bhatia SP, Letizia CS, Api AM, Food and Chemical Toxicology 2008 (PubMed 18640180)
Household disinfectant ingredient	Hospital case reports from 1978 and 1984 describe poisonings with Dettol, a disinfectant whose titles name chloroxylenol and terpineol as ingredients.	Shipton EA et al., South African Medical Journal 1984 (PubMed 6505887)
Traditional use of plants that contain it (not of the pure molecule)	An abstract says the oil of Pinus roxburghii, which contains 2.8 to 5.0% alpha-terpineol, is traditionally used for cuts, wounds, boils and blisters in Nepal. Another says the resin of Protium heptaphyllum, rich in alpha-terpineol, is used by Brazilian indigenous tribes for heart conditions. These describe the plants, not alpha-terpineol itself.	Satyal P et al. 2013 (PubMed 23598924); Paulino ET et al. 2022 (PubMed 34740575)
Name and first isolation	NOT verified. When and by whom terpineol was first isolated or named was not found in any source read.	none

History shows how a substance was used or discovered. It does not show that a product works or is safe today.

What is inside, and how it may work

What it 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
alpha-Terpineol (unspecified mirror form) PubChem 17100	Monoterpene alcohol	Essential oils of tea tree, cajuput, pine, eucalyptus and other plants; cannabis flower Varies by plant and batch; see 'What the lab numbers show' on the Overview tab for measured cannabis values and their units.	Studied in mice for pain, in cells for inflammation and cancer, in rats for stomach and heart effects. No human trial alone. ^{23 41 3 8}	Animal research
(R)-(+)-alpha-Terpineol and (S)-(-)-alpha-Terpineol PubChem 442501	Monoterpene alcohol (mirror forms)	Not stated in the sources read	Most abstracts do not say which mirror form was used. CID 442501 is the (R)-(+) form and CID 443162 the (S)-(-) form. ³³	Laboratory research
beta-Terpineol PubChem 8748	Monoterpene alcohol	Not studied here	Listed with alpha-terpineol on the FDA synthetic flavouring list. No research read. ³¹	Insufficient
gamma-Terpineol PubChem 11467	Monoterpene alcohol	Not stated	Slowed liver cancer cell growth and caused cell-death signs in a dish (320 micrograms/mL gave a DNA ladder). Not alpha-terpineol. ³⁷	Laboratory research
Terpinen-4-ol (4-terpineol) PubChem 11230	Monoterpene alcohol	Tea tree oil (37.66-44.28% in seven oils); some pine oil (4.1-30.1% in one pine) 37.66-44.28% of tea tree oil	Used in eyelid wipes for Demodex mites; one open-label 40-person trial and a patch test of a 2% foam. A different molecule from alpha-terpineol. ^{35 30 34}	Low
Other cannabis terpenes measured with it	Terpenes	Cannabis flower Alpha-pinene, beta-pinene, myrcene, limonene, terpinolene, linalool, beta-caryophyllene, alpha-humulene and caryophyllene oxide are measured in the same lab methods.	Each has its own page. They are different molecules. ^{11 12}	N/a

Mechanisms, receptors and pathways

Target or pathway	Gene or receptor	What was found	Level
NF-kappaB signalling	NFKB1 / RELA pathway	In human tumour cell lines alpha-terpineol reduced NF-kappaB movement and activity and turned down NF-kappaB-related genes (IL-1 beta, IL1R1). ⁸	Lab
Inflammatory cytokines in macrophages	IL1B, IL6, IL10	In stimulated human macrophages alpha-terpineol lowered IL-1 beta, IL-6 and IL-10 but not TNF-alpha. The abstract is inconsistent about whether NF-kappaB or p38 MAPK was involved. ¹⁹	Lab
IL-6 receptor expression	IL6R	In human oral cells, alpha-terpineol lowered IL-6 formation and IL-6 receptor gene expression. ¹⁰	Lab
Nitric oxide / cGMP / KATP channel pathway	NOS, guanylyl cyclase, KATP channels	In mice the pain relief was reduced by L-NAME, methylene blue and glibenclamide and boosted by L-arginine, pointing to this pathway. ²⁶	Animal research
Inducible nitric oxide synthase (iNOS)	NOS2	In tumour-bearing mice alpha-terpineol lowered iNOS in tumours; computer docking suggested it binds in the same region as known iNOS blockers. ⁷	Animal research
Cannabinoid receptors CB1 and CB2	CNR1, CNR2	In nerve-injured mice, alpha-terpineol was 2.91 times less potent without CB1 and 11.73 times less potent without CB2. In frog egg cells with human receptors, terpineol boosted THC activation of CB1. Direct binding was not shown in the abstracts. ^{3 24}	Animal research
Vagal cholinergic and nitrergic signalling in the stomach	Muscarinic receptors, NOS	In rats, slower stomach emptying was removed by atropine and L-NAME and did not occur after vagotomy. ³⁹	Animal research
Arachidonic acid metabolism (5-lipoxygenase and cysteinyl leukotrienes)	ALOX5	In asthmatic mice, alpha-terpineol lowered arachidonic acid, 5-lipoxygenase and cysteinyl leukotrienes in lung tissue. ²⁵	Animal research
KDELC2 and Notch / PI3K / mTOR / MAPK signalling	KDELC2	In glioblastoma cells alpha-terpineol targeted KDELC2 and lowered these pathways; the authors report it reached the brain in mice. ¹⁵	Lab
Skeletal patterning genes	HOXD13, GDF11	In rat fetuses exposed to alpha-terpineol, expression of HOXD13 and GDF11 was lower, alongside malformations. ⁹	Animal research
Bacterial membranes	Not applicable	Alpha-terpineol with colistin disrupted membranes of colistin-resistant Gram-negative bacteria and raised reactive oxygen species in the lab. ³⁸	Lab

Absorption, metabolism and elimination

Absorption: No human data were found for alpha-terpineol by mouth, by inhalation, through the skin or from cannabis. The animal studies used doses of 10 to 300 mg/kg by mouth or injection.
Distribution: In a glioblastoma mouse model the authors report that alpha-terpineol penetrated the blood-brain barrier. No human tissue data.
Metabolism: Not described in any human source read. No human liver enzyme (CYP) study was found.
Elimination: No data found.
Bioavailability: Not established for any route or product. Nothing is known about blood levels from cannabis flower or vaporised terpenes.

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12benefits and uses looked at

41studies and sources checked

Very low certaintybest evidence rating found

12lab markers tracked in trials

8 very low certainty4 not enough evidence

What was looked at

The 12 benefits and uses checked for Terpineol, each with how strong the evidence is. Tap one to open it.

Pain in mice (not people)Very low certainty
Cancer-related pain in mice (not people)Very low certainty
Anxiety-like behaviour in rats (no effect named)Not enough evidence
Sleep (a mixture that contains it)Not enough evidence
Working with THC at cannabis receptors (lab)Not enough evidence
Inflammation signals in cells and miceVery low certainty
Airway inflammation in asthmatic miceVery low certainty
Cancer cells in dishes and mice (not a treatment)Very low certainty
Stomach protection and slower emptying in ratsVery low certainty
Heart damage from a drug in ratsVery low certainty
Killing germs in dishesNot enough evidence
NOT TERPINEOL: terpinen-4-ol for eyelid mitesVery low certainty

Lab markers tracked in the studies

Pain behaviour in mice (paw licking, writhing, touch and heat sensitivity)iNOS protein in mouse tumoursShare of the night in slow-wave plus REM sleep (wrist device)THC activation of the CB1 receptor in egg cellsInterleukin-6 (IL-6) and IL-1 beta in cellsWhite-cell (neutrophil) influx in mouse pleurisyWhite cells and cytokines in airway fluid (mouse asthma)Survival of tumour cells in a dishStomach ulcer score in ratsSpeed of stomach emptying in ratsHeart damage markers and infarct size in ratsDemodex mite count on eyelashes (terpinen-4-ol, not terpineol)

What is Terpineol good for?

The uses people ask about and how strong the evidence is for each. For terpineol, almost all of it is from animals or cells, and no trial has tested alpha-terpineol on its own in people. The last row is a different molecule and is shown only to avoid confusion.

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.

Pain in mice (not people)

Very low certainty

In several mouse tests, injected alpha-terpineol reduced pain behaviour. Nobody has tested it for pain in people.

4 studiesPure alpha-terpineol injected or given in lab doses, not a scent, not…

Studies, doses and limits

Results

Mice given alpha-terpineol licked their paws less in the formalin test, writhed less, and were protected in glutamate, capsaicin and carrageenan tests. In a nerve-injury model it reversed touch and heat pain behaviour, with alpha-terpineol the most potent of three terpenes tested.

Effect sizes as reported

In nerve-injured mice alpha-terpineol was 2.91 times less potent without CB1 receptors and 11.73 times less potent without CB2 receptors. Other results are significance values only in the abstracts.

Why this rating

Every result is from mice, with injected doses. There is no human study. The mechanism findings come from blocker drugs and knockout mice.

Form and dose studied

Pure alpha-terpineol injected or given in lab doses, not a scent, not cannabis flower and not an oil from a shop.

Who was studied

Mice (several strains), including mice with nerve injury.

Limits

Animal pain tests do not predict pain relief in people. Doses were milligrams per kilogram of body weight. Several abstracts do not give doses.

Why researchers looked

Alpha-terpineol is a common scent molecule in eucalyptus and other plant oils. Brazilian, Iranian and American teams asked whether it relieves pain in animals, partly because cannabis contains it.

Proposed mechanism Animal research

In mice the pain relief depended on the nitric oxide / cGMP / potassium-channel pathway, and on working CB1 and CB2 cannabinoid receptors for full potency. Whether people respond the same way is unknown.

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

Do not use these results to treat pain. The same terpene can irritate skin and eyes (see the Safety tab).

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Cancer-related pain in mice (not people)

Very low certainty

In mice with a tumour, alpha-terpineol reduced pain behaviour without shrinking the tumour. This is one mouse study.

1 studiesPure alpha-terpineol in mice.

Studies, doses and limits

Results

Alpha-terpineol significantly reduced mechanical pain sensitivity and spontaneous and palpation-induced pain behaviour in mice with sarcoma 180 tumours and improved paw use, without reducing tumour growth or grip strength. The authors saw no evident blood-chemistry or blood-count toxicity.

Effect sizes as reported

Not given in the abstract.

Why this rating

One mouse tumour model, doses not given in the abstract, and a computer-docking prediction.

Form and dose studied

Pure alpha-terpineol in mice.

Who was studied

Swiss mice with sarcoma 180 tumours.

Limits

One study from one research network, no replication, no human data.

Why researchers looked

People with cancer often have pain that is hard to treat, so researchers tried a plant terpene in a mouse tumour model.

Proposed mechanism Animal research

The study found higher antioxidant capacity and lower iNOS (an inflammation-linked enzyme) in tumours. A computer model suggested it could bind iNOS. This was not tested in people.

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

Not a cancer treatment and not a pain treatment for people.

⁷

Anxiety-like behaviour in rats (no effect named)

Not enough evidence

In one rat study that tested many cannabis compounds, alpha-terpineol is not named among the terpenes with an anxiety-lowering effect.

1 studiesPure alpha-terpineol 10 mg/kg by mouth in oil.

Studies, doses and limits

Results

The abstract names D-limonene, bisabolol, alpha-pinene and beta-caryophyllene as showing signs of lower anxiety in the novelty-feeding test. Alpha-terpineol (10 mg/kg by mouth) is not named, and the abstract says the compounds did not change general movement.

Effect sizes as reported

Not given.

Why this rating

Only the abstract was read and it names no alpha-terpineol result. One dose, males only, one test battery.

Form and dose studied

Pure alpha-terpineol 10 mg/kg by mouth in oil.

Who was studied

Adult male rats, 7 to 8 per group.

Limits

Cannot confirm from the abstract that alpha-terpineol was tested in every test; a full-text read would be needed. A single dose may have been too low or too high.

Why researchers looked

Cannabis users often talk about terpenes changing mood. Researchers tested minor cannabinoids and terpenes in rats given a single oral dose.

Proposed mechanism Animal research

No mechanism is reported for alpha-terpineol in this study.

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

None reported.

¹³

Sleep (a mixture that contains it)

Not enough evidence

One company-funded trial gave 125 people with insomnia a mix of 300 mg CBD and eight terpenes, including alpha-terpineol. Sleep improved slightly. The trial cannot say what alpha-terpineol did.

1 studiesAn oral capsule with CBD and eight terpenes at 1 mg each. It is not a…

Studies, doses and limits

What the trials found

In a double-blind, placebo-controlled crossover trial of 125 adults with insomnia, 300 mg CBD with 1 mg each of eight terpenes (linalool, myrcene, phytol, limonene, alpha-terpinene, alpha-terpineol, alpha-pinene, beta-caryophyllene) for at least 4 days a week over 4 weeks raised the share of the night in slow-wave plus REM sleep by 1.3 percentage points compared with placebo (P = .03).

Results

A small average gain in slow-wave plus REM sleep with the mixture; no change in total sleep time.

Effect sizes as reported

Mean gain 1.3% (standard error 0.60%; 95% CI 0.1 to 2.5%). Total sleep time, resting heart rate and heart rate variability did not change. No adverse events were reported.

Why this rating

For alpha-terpineol itself there is no evidence: it was one of nine active ingredients, the average gain was marginal and was measured by a wrist-worn device, and the company that makes the product ran and funded the study.

Form and dose studied

An oral capsule with CBD and eight terpenes at 1 mg each. It is not alpha-terpineol alone and not cannabis flower.

Who was studied

125 adults with insomnia.

Limits

Cannot assign the effect to alpha-terpineol. Funded by a company whose staff hold equity. Short (4 weeks).

Why researchers looked

People look for sleep aids and cannabis products often add terpenes. A company tested a CBD-terpene capsule.

Proposed mechanism None

Not tested. The trial did not isolate any single ingredient.

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

No adverse events were reported in the trial. This does not make the mixture risk-free.

³⁶

Working with THC at cannabis receptors (lab)

Not enough evidence

In frog egg cells carrying human cannabinoid receptors, terpineol made THC's effect at the CB1 receptor stronger than expected. This is a cell experiment, not an effect in people.

2 studiesPure terpenes and THC applied to cells.

Studies, doses and limits

Results

In oocytes expressing human CB1 or CB2, several terpenes boosted THC activation. Terpineol was among the terpenes with a synergistic interaction at CB1, with borneol, limonene, sabinene, alpha-pinene and ocimene.

Effect sizes as reported

Not given in the abstract.

Why this rating

Egg cells carrying human receptors do not tell us what happens in a person who inhales or swallows cannabis.

Form and dose studied

Pure terpenes and THC applied to cells.

Who was studied

Frog egg cells (Xenopus laevis oocytes).

Limits

Authors include employees of a medical cannabis maker. Which terpineol isomer was used is not stated in the abstract.

Why researchers looked

People ask whether cannabis terpenes change how THC feels (the 'entourage effect'). Researchers tested terpenes with THC in cells.

Proposed mechanism Lab and animal

The authors suggest cannabis terpenes can act as weak partial agonists or allosteric modulators (helpers that change how a receptor responds). In mice, alpha-terpineol's pain effect was weaker when CB1 or CB2 was missing, which fits an indirect link.

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

A stronger THC signal in a dish is not shown to be safer or more harmful in people. THC risks such as anxiety, impairment and dependence are covered on the THC page.

^{24 3}

Inflammation signals in cells and mice

Very low certainty

In dishes, alpha-terpineol lowered inflammation messengers such as IL-6, IL-1 beta and nitrite. In mice it reduced white-cell influx. No human study.

3 studiesPure alpha-terpineol on cells, or injected in mice.

Studies, doses and limits

Results

In lipopolysaccharide-stimulated human macrophages, alpha-terpineol significantly reduced IL-1 beta, IL-6 and IL-10. In mouth cells it lowered IL-6 and IL-6 receptor gene expression. In mice it reduced neutrophil influx in pleurisy, and in mouse macrophages it lowered nitrite production.

Effect sizes as reported

Significance values only; effect sizes are not given in the abstracts.

Why this rating

Cell dishes and mice. No human study. One abstract is internally inconsistent about the pathway.

Form and dose studied

Pure alpha-terpineol on cells, or injected in mice.

Who was studied

Human macrophage and mouth cell lines; mice.

Limits

Cell results often do not carry over to the body. Amounts used in dishes are not the amounts from a scent or from cannabis.

Why researchers looked

Inflammation is part of many conditions, and terpenes from tea tree oil, orange juice and eucalyptus were tested in cells.

Proposed mechanism Lab

Lab findings include lower IL-1 beta, IL-6 and IL-10 production in human macrophages (TNF-alpha unchanged) and lower IL-6 receptor gene expression in mouth cells. The abstract on macrophages is inconsistent about which pathway is responsible.

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

Do not rely on a terpene to treat inflammation.

^{19 10 41}

Airway inflammation in asthmatic mice

Very low certainty

In mice made asthmatic with ovalbumin, alpha-terpineol before challenge reduced airway inflammation and mucus.

1 studiesPure alpha-terpineol in mice; the dose is not given in the abstract.

Studies, doses and limits

Results

Treated mice had fewer white cells and lower inflammatory cytokines in airway fluid, less inflammation around the airways, less mucus-producing cell overgrowth and lower Muc5ac.

Effect sizes as reported

Not given in the abstract.

Why this rating

One mouse study, pre-treatment rather than treatment of established asthma.

Form and dose studied

Pure alpha-terpineol in mice; the dose is not given in the abstract.

Who was studied

Mice with ovalbumin asthma.

Limits

No human asthma data. Strong scents and vapours can bother some people's airways.

Why researchers looked

Alpha-terpineol has been called an expectorant and anti-inflammatory, so researchers tested it in a mouse asthma model.

Proposed mechanism Animal research

Metabolite tests suggested changes in arachidonic acid handling: lower 5-lipoxygenase and fewer cysteinyl leukotrienes in lung tissue.

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

People with asthma should not assume a terpene is safe to vaporise or inhale.

²⁵

Cancer cells in dishes and mice (not a treatment)

Very low certainty

Alpha-terpineol killed or slowed several kinds of tumour cells in dishes, and slowed glioblastoma in one mouse model. Nothing is known in people.

4 studiesPure alpha-terpineol on cells or in mice.

Studies, doses and limits

Results

Viability of mouse sarcoma 180 cells fell to 50.9%, 38.53% and 30.82% at 100, 250 and 500 micrograms/mL. Glioblastoma growth, spread and temozolomide resistance fell in the lab, and a mouse model showed slower tumour growth. A separate paper on GAMMA-terpineol (a different isomer) slowed liver cancer cells.

Effect sizes as reported

Only percentages of surviving cells; no survival or tumour-size numbers in people.

Why this rating

Cells and mice only. The DNA damage that kills tumour cells in the dish is also a safety signal.

Form and dose studied

Pure alpha-terpineol on cells or in mice.

Who was studied

Cell lines; mice.

Limits

Authors of one paper call alpha-terpineol a 'promising alternative therapeutic option'; the data cannot support that for people.

Why researchers looked

Many plant molecules kill cancer cells in dishes. Researchers wanted to know whether alpha-terpineol works through the NF-kappaB pathway.

Proposed mechanism Lab and animal

Lab findings: lower NF-kappaB activity (small cell lung carcinoma cells most sensitive); DNA damage and cell death in mouse sarcoma cells; lower KDELC2 and Notch / PI3K / mTOR / MAPK signalling in glioblastoma cells.

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

Do not use terpineol, tea tree oil, pine oil or cannabis instead of cancer treatment.

^{8 18 15 37}

Stomach protection and slower emptying in rats

Very low certainty

In rats, alpha-terpineol protected against alcohol-induced stomach ulcers and slowed stomach emptying. No human study.

2 studiesPure alpha-terpineol by mouth in rats.

Studies, doses and limits

Results

Oral alpha-terpineol (10, 30, 50 mg/kg) protected against ethanol-induced ulcers; 50 mg/kg delayed emptying of a liquid meal at 10 minutes; it relaxed isolated stomach strips.

Effect sizes as reported

Significance values only in the abstracts.

Why this rating

Rat studies; one ulcer-model result was unclear in the abstract and was not used.

Form and dose studied

Pure alpha-terpineol by mouth in rats.

Who was studied

Rats and isolated stomach tissue.

Limits

No data for heartburn, ulcers or digestion in people.

Why researchers looked

Plant terpenes are often tested for stomach effects; a Brazilian team looked at ulcers and emptying.

Proposed mechanism Animal research

Slower emptying needed the vagus nerve and was blocked by atropine and L-NAME. Ulcer protection did not depend on extra prostaglandins or less acid.

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

Slower stomach emptying could matter for how quickly an oral medicine is absorbed; this has not been studied in people.

^{29 39}

Heart damage from a drug in rats

Very low certainty

In rats, alpha-terpineol by mouth for 15 days reduced heart damage caused by the drug isoproterenol.

1 studiesPure alpha-terpineol by mouth in rats.

Studies, doses and limits

Results

Alpha-terpineol (25, 50, 75 mg/kg) significantly reduced death, heart-damage enzymes, fast heart rate, tissue death, swelling and infarct size caused by isoproterenol.

Effect sizes as reported

Significance values only.

Why this rating

A drug-injury model in rats. It does not resemble how heart attacks happen in people.

Form and dose studied

Pure alpha-terpineol by mouth in rats.

Who was studied

Wistar and Wistar-Kyoto rats.

Limits

No human data. A related 2026 paper on nitric oxide in heart tissue appeared but was not read.

Why researchers looked

A plant resin rich in alpha-terpineol is used in Brazilian traditional medicine for heart disease, and earlier work saw blood-vessel relaxing and blood-pressure effects.

Proposed mechanism Animal research

Not established in the abstract.

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

Not a treatment or prevention for heart disease.

²²

Killing germs in dishes

Not enough evidence

Alpha-terpineol slowed or killed mouth bacteria in the lab and boosted the antibiotic colistin against resistant bacteria in the lab.

2 studiesPure alpha-terpineol in culture.

Studies, doses and limits

Results

Alpha-terpineol and linalool showed strong antimicrobial activity against gum-disease and tooth-decay bacteria, and the authors advise keeping concentrations below 0.4 mg/mL for toothpaste or gargles. With colistin it was synergistic against colistin-resistant Gram-negative bacteria and cleared biofilms.

Why this rating

Lab cultures; no person was treated.

Form and dose studied

Pure alpha-terpineol in culture.

Who was studied

Bacteria in the lab.

Limits

No dosing or safety data in people; antiseptic strength in a dish is not the same as a safe, effective treatment.

Why researchers looked

Tea tree oil and pine oil are traditional skin and wound remedies, and researchers asked which components may do the work.

Proposed mechanism Lab

In the colistin study the combination damaged bacterial membranes and raised reactive oxygen species.

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

Never swallow disinfectants. Do not combine terpineol products with antibiotics unless a doctor says so.

^{21 38}

NOT TERPINEOL: terpinen-4-ol for eyelid mites

Very low certainty

Terpinen-4-ol is a different molecule from alpha-terpineol. Wipes with terpinen-4-ol reduced eyelid mites in a small open-label trial. This does not apply to alpha-terpineol.

2 studiesTerpinen-4-ol wipes or foam, used under eye-clinic care.

Studies, doses and limits

What the trials found

In a randomised open-label trial of 40 people with Demodex blepharitis, terpinen-4-ol wipes cut mite counts after two months, but mites rose again when wipes alone were stopped. Adding deep eyelid cleaning gave a lasting gain. A separate lab and patch test of a 2% foam found no skin or eye irritation or sensitisation.

Results

Fewer eyelid mites during treatment, and a rebound after wipes alone were stopped; no skin or eye reaction to a 2% foam in the patch test.

Effect sizes as reported

Mite counts fell by 5.65 (wipes) and 7.75 (wipes plus cleaning); third-month difference between the groups 8.70 versus 4.15 (P = 0.043).

Why this rating

Small open-label trial, no placebo group; the second paper's senior author holds patents. It is about a different molecule.

Form and dose studied

Terpinen-4-ol wipes or foam, used under eye-clinic care.

Who was studied

40 adults (trial); human volunteers in the patch test.

Limits

These results are included only so readers do not confuse the two molecules.

Why researchers looked

Terpinen-4-ol is the main part of tea tree oil. Eye clinics use it for Demodex mite infection of the eyelids. It is often written 4-terpineol, which is why it is mixed up with terpineol.

Proposed mechanism Human data

Not covered here.

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

Do not put tea tree oil or any terpene near the eyes without an eye doctor's advice.

^{35 30}

Connections to the rest of health

How Terpineol 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

B. Body systems

Connected to	Kind of connection	Evidence status	Context	Studies
Nervous System	Biological association	Very low certainty	Studied for: Pain in mice (not people) Studied for: Cancer-related pain in mice (not people)	^{23 41 26 3 7 13 36 24}
Immune System	Biological association	Very low certainty	Studied for: Inflammation signals in cells and mice Studied for: Cancer cells in dishes and mice (not a treatment)	^{19 10 41 8 18 15 37 21 38 35 30}
Respiratory System	Biological association	Very low certainty	Studied for: Airway inflammation in asthmatic mice	²⁵
Digestive System	Biological association	Very low certainty	Studied for: Stomach protection and slower emptying in rats	^{29 39}
Cardiovascular System	Biological association	Very low certainty	Studied for: Heart damage from a drug in rats	²²

C. Body parts and organs

Connected to	Kind of connection	Evidence status	Context	Studies
Skin	Adverse effect or risk	Low certainty	Skin irritation is the most common notified hazard class; allergy is documented for tea tree oil as a whole. Preparation or compound: Pure alpha-terpineol; essential oils that contain it	^{32 40}
Eyes	Adverse effect or risk	Low certainty	Serious eye irritation is a notified hazard class. Preparation or compound: Pure alpha-terpineol	³²
Pregnancy (fetal development)	Adverse effect or risk	Very low certainty	One 2026 rat study found skeletal malformations at 75 to 300 mg/kg; no human data. Preparation or compound: Alpha-terpineol in pregnant rats	⁹

I. Biomarkers

Connected to	Kind of connection	Evidence status	Context	Studies
Pain behaviour in mice (paw licking, writhing, touch and heat sensitivity)	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{23 3 7 26}
iNOS protein in mouse tumours	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	⁷
Share of the night in slow-wave plus REM sleep (wrist device)	Biological association	Not enough evidence	Measured in trials: raised. A lab change is not the same as a health benefit.	³⁶
THC activation of the CB1 receptor in egg cells	Biological association	Not enough evidence	Measured in trials: raised. A lab change is not the same as a health benefit.	²⁴
Interleukin-6 (IL-6) and IL-1 beta in cells	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{19 10}
White-cell (neutrophil) influx in mouse pleurisy	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	⁴¹
White cells and cytokines in airway fluid (mouse asthma)	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	²⁵
Survival of tumour cells in a dish	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{18 8 15}
Stomach ulcer score in rats	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	²⁹
Speed of stomach emptying in rats	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	³⁹
Heart damage markers and infarct size in rats	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	²²
Demodex mite count on eyelashes (terpinen-4-ol, not terpineol)	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	³⁵

L. Active compounds

Connected to	Kind of connection	Evidence status	Context	Studies
alpha-Terpineol (unspecified mirror form)	Biological association	Animal	Studied in mice for pain, in cells for inflammation and cancer, in rats for stomach and heart effects. No human trial alone. Preparation or compound: Essential oils of tea tree, cajuput, pine, eucalyptus and other plants; cannabis flower	^{23 41 3 8}
(R)-(+)-alpha-Terpineol and (S)-(-)-alpha-Terpineol	Biological association	In vitro	Most abstracts do not say which mirror form was used. CID 442501 is the (R)-(+) form and CID 443162 the (S)-(-) form.	³³
beta-Terpineol	Biological association	Not enough evidence	Listed with alpha-terpineol on the FDA synthetic flavouring list. No research read. Preparation or compound: Not studied here	³¹
gamma-Terpineol	Biological association	In vitro	Slowed liver cancer cell growth and caused cell-death signs in a dish (320 micrograms/mL gave a DNA ladder). Not alpha-terpineol.	³⁷
Terpinen-4-ol (4-terpineol)	Biological association	Low certainty	Used in eyelid wipes for Demodex mites; one open-label 40-person trial and a patch test of a 2% foam. A different molecule from alpha-terpineol. Preparation or compound: Tea tree oil (37.66-44.28% in seven oils); some pine oil (4.1-30.1% in one pine)	^{35 30 34}
Other cannabis terpenes measured with it	Biological association	N/a	Each has its own page. They are different molecules. Preparation or compound: Cannabis flower	^{11 12}

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 12 lab markers

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

Other102

The evidence

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

Evidence by outcome

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 read the abstracts of about 38 sources, read the EFSA cajuput oil opinion in full through PubMed Central, read the FDA flavouring list through the Electronic Code of Federal Regulations, read PubChem for chemical identity and hazard notifications, and used our own cultivar lab-data file for the cannabis numbers. We say which sources we could not read.

Study library: every study we checked 41

Design Research type Year from Search

Study	Design	People	Product, dose, length	Result
Ankney 2022 Essential Oil Compositions of Pinus Species (P. contorta Subsp. contorta, P. ponderosa var. ponderosa, and P. flexilis); Enantiomeric Distribution of Terpenoids in Pinus Species. Molecules · PMID 36080426 · DOI	Chemical analysis plant oil	Needle oils of three western North American pines	Essential oils by hydrodistillation; GC and chiral GC Pine needle	In Pinus ponderosa var. ponderosa leaf oil, beta-pinene (21.5-55.3%), methyl chavicol (8.5-41.5%), alpha-pinene (3.6-9.6%), delta-3-carene (3.6-6.2%) and alpha-terpineol (1.4-5.3%) were the main compounds. P. contorta oil was dominated by beta-phellandrene and terpinen-4-ol; P. flexilis by alpha-pinene, beta-pinene, bornyl acetate and camphene (no alpha-terpineol named for those two). One pine species oil with 1.4 to 5.3% alpha-terpineol; others do not name it Methods, limits and funding Outcomes: Chemical composition Limitations: Three pine species; amounts differ between trees. Funding and conflicts: No conflict of interest declared. Read: abstract
Bhatia 2008 Fragrance material review on alpha-terpineol. Food Chem Toxicol · PMID 18640180 · DOI	Safety assessment review	Fragrance-ingredient safety review	Alpha-terpineol as a fragrance ingredient Isolated compound Not given	The PubMed record is a title and one-line summary only ('a toxicologic and dermatologic review of alpha-terpineol when used as a fragrance ingredient is presented'). The findings were not available to read. A review exists; its findings were not read Methods, limits and funding Outcomes: Toxicology and dermatology review of alpha-terpineol as a fragrance ingredient Limitations: No results visible, so none are used. The later updated assessments of 'terpineol' (CAS 8000-41-7) by the same industry research institute are listed on PubMed (2017: PubMed 28743522; 2024: PubMed 38228281) but their abstracts also contain no findings. Funding and conflicts: Written by staff of the Research Institute for Fragrance Materials, an industry body (affiliation not shown in the abstract). Read: abstract
Bilbrey 2022 Evaluation of the terpenes β-caryophyllene, α-terpineol, and γ-terpinene in the mouse chronic constriction injury model of neuropathic pain: possible cannabinoid receptor involvement. Psychopharmacology (Berl) · PMID 34846548 · DOI	Animal research mouse	Mice with chronic constriction injury of the sciatic nerve (a neuropathic pain model), including mice lacking CB1 or CB2 receptors	Alpha-terpineol, beta-caryophyllene or gamma-terpinene, given as single doses Isolated compounds Dose ranges not given in the abstract Acute tests · vs Wild-type mice and vehicle	Each terpene gave dose-related reversal of mechanical allodynia and thermal hyperalgesia; the order of potency was alpha-terpineol, then beta-caryophyllene, then gamma-terpinene. In mice lacking CB1 receptors, alpha-terpineol was 2.91 times less potent at reversing mechanical allodynia, and in mice lacking CB2 receptors 11.73 times less potent. Each terpene also produced some effects on movement, body temperature or acute pain tests. Less nerve-pain behaviour in mice; the effect needed working cannabinoid receptors to be fully potent Methods, limits and funding Outcomes: Mechanical allodynia (von Frey), thermal hyperalgesia (hot plate), locomotion, body temperature, acute pain Limitations: Mice, injected doses, nerve-injury model. The knockout result suggests the terpene works partly through cannabinoid receptors indirectly; the abstract does not show that it binds them. Not evidence for people. Funding and conflicts: Not stated in the abstract. Read: abstract
EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) 2024 Safety and efficacy of a feed additive consisting of an essential oil derived from fresh leaves of Melaleuca cajuputi Maton & Sm. ex R. Powell and Melaleuca leucadendra (L.) L. (cajuput oil) for use in all animal species (FEFANA asbl). EFSA J · PMID 38601874 · DOI	Authoritative guidance plant oil	EFSA safety assessment of cajuput oil as an animal feed additive	Cajuput oil from fresh leaves of Melaleuca cajuputi and Melaleuca leucadendra Essential oil Safe use levels of 5 to 78 mg/kg complete feed depending on species	The full text (read via PubMed Central) lists alpha-terpineol at a mean of 7.87% (range 6.53 to 9.28%) in five batches of cajuput oil, next to 1,8-cineole (61.46%) and d-limonene (6.23%). It lists alpha-terpineol (FLAVIS number 02.014) among the components in the EU register of flavouring substances. For risk calculations it applies a no-observed-adverse-effect level of 250 mg/kg body weight per day from subchronic data on terpineol (taken from earlier EFSA opinions that were not read). It concludes the oil is an irritant to skin and eyes and a dermal and respiratory sensitiser. Cajuput oil is about 8% alpha-terpineol; EFSA calls the whole oil a skin and eye irritant and a sensitiser Methods, limits and funding Outcomes: Safety and efficacy of the oil in animal feed; composition Limitations: A feed-additive opinion for animals, not people. The sensitiser label is for the whole oil, not for alpha-terpineol alone. The 250 mg/kg figure is quoted second-hand. Funding and conflicts: EFSA panel opinion; declarations of interests are held by EFSA. Read: full-text
Fischedick 2017 Identification of Terpenoid Chemotypes Among High (-)-trans-Δ(9)- Tetrahydrocannabinol-Producing Cannabis sativa L. Cultivars. Cannabis Cannabinoid Res · PMID 28861503 · DOI	Chemical analysis plant material	233 233 cannabis samples from one medical dispensary in California over a year, representing 30 cultivars	Terpenoid content by GC-FID with GC-MS confirmation Dried cannabis flower	Sixteen major terpenoids were measured and used to sort the cultivars into five groups and 13 classes. Some cultivars fit distinct chemotypes and others a continuum. Alpha-terpineol values for named cultivars used on this page come from this paper's dataset as recorded in our lab-data file (Excelsior Analytical Laboratory, Union City, California; GC-FID). Cannabis terpene profiles differ by cultivar but overlap Methods, limits and funding Outcomes: Terpenoid chemotypes of high-THC cultivars Limitations: One dispensary, one year. The abstract has no alpha-terpineol numbers; those come from the paper's data as read earlier for our cultivar lab-data file. Funding and conflicts: No competing financial interests reported. Read: abstract
Friedrich 2007 Assessment of sensitization potential of monoterpenes using the rat popliteal lymph node assay. Food Chem Toxicol · PMID 17383062 · DOI	Animal research rat	Female Wistar rats	Ten monoterpenes injected into the hind footpad (0.5, 2.5 or 5 mg), including terpineol Isolated compounds 0.5-5 mg per paw Lymph node weight and cell counts after 7 days · vs Chlorpromazine (positive), barbital (negative), vehicle	The primary test was negative for terpineol (as for menthol, 1,8-cineole, citronellal, limonene and camphor) and positive for citral, alpha-terpinene, beta-myrcene and (-)-alpha-pinene. The authors summarise that no monoterpene proved to be a sensitising agent in this test; the positive ones acted as irritants. Terpineol did not trigger the lymph node screening test Methods, limits and funding Outcomes: Popliteal lymph node assay (a screening test for skin-sensitising and immune-stimulating chemicals) Limitations: A rat screening test, injected under the skin; it is not a human patch test. The abstract says 'terpineol' without naming which isomer. Funding and conflicts: Not stated in the abstract. Read: abstract
Gouveia 2018 α-Terpineol reduces cancer pain via modulation of oxidative stress and inhibition of iNOS. Biomed Pharmacother · PMID 29902764 · DOI	Animal research mouse	Swiss mice with sarcoma 180 tumours	Alpha-terpineol (TP) Isolated compound Doses not given in the abstract Not given in the abstract · vs Vehicle	Alpha-terpineol significantly reduced mechanical hyperalgesia and spontaneous and palpation-induced pain behaviour and improved paw use, without reducing tumour growth or grip strength. No evident biochemical or blood toxicity was seen. It raised tissue antioxidant capacity (FRAP and glutathione) and lowered iNOS protein in tumours. Computer docking suggested it fits where known iNOS blockers bind. Less cancer-related pain behaviour in mice, with no change in tumour size Methods, limits and funding Outcomes: Cancer pain behaviours, tumour growth, grip strength, blood chemistry, antioxidant markers, iNOS in tumours Limitations: Mouse tumour model. The docking result is a computer prediction. Not evidence for people. The authors' wording ('strong evidence') goes beyond what a mouse study can show. Funding and conflicts: Not stated in the abstract. Read: abstract
Hassan 2010 Alpha terpineol: a potential anticancer agent which acts through suppressing NF-kappaB signalling. Anticancer Res · PMID 20651334	Laboratory research cells	Human tumour cell lines	Alpha-terpineol (a component of Salvia libanotica essential oil) Isolated compound Concentrations not given in the abstract Cell culture · vs Untreated cells	Small cell lung carcinoma cells were the most sensitive. NF-kappaB activity and movement into the nucleus fell in a dose-dependent way in two assays, and NF-kappaB-related genes such as IL-1 beta and IL1R1 were turned down. The authors suggest alpha-terpineol slows tumour cell growth by blocking the NF-kappaB pathway. Killed or slowed tumour cells in dishes, with lower NF-kappaB activity Methods, limits and funding Outcomes: Cell killing across a tumour cell panel; NF-kappaB movement and activity; gene expression Limitations: Cells only. Says nothing about whether it would act in the body or be safe. Funding and conflicts: Not stated in the abstract. Read: abstract
Hegde 2026 Alpha-terpineol induced developmental toxicity in Wistar rats: Embryotoxic, teratogenic, and targeted gene expression effects. Toxicol Appl Pharmacol · PMID 41932552 · DOI	Animal research rat	Pregnant Wistar rats	Alpha-terpineol at 0, 75, 150 and 300 mg/kg (5 mL/kg dose volume) during organogenesis Isolated compound 75, 150, 300 mg/kg During the organ-forming period of pregnancy · vs 0 mg/kg	The authors report dose-dependent embryo toxicity and teratogenic effects: lower fetal weight and a range of skeletal malformations (including anophthalmia, club foot, micrognathia, phocomelia, and irregular spine, rib and limb bones). Expression of the HOXD13 and GDF11 genes, important for skeleton and limb patterning, was lower. Fetal harm and malformations in rats at 75 to 300 mg/kg Methods, limits and funding Outcomes: Fetal weight, malformations, expression of limb and skeleton genes Limitations: One 2026 study, not yet repeated that we know of. Doses are far above what anyone gets from scent or cannabis. Route is not stated in the abstract. It cannot be used to estimate human risk, but it is a reason for caution in pregnancy. Funding and conflicts: The authors hold an Indian patent on a fetal-staining technique; no other conflict stated. Read: abstract
Held 2007 Characterization of alpha-terpineol as an anti-inflammatory component of orange juice by in vitro studies using oral buccal cells. J Agric Food Chem · PMID 17867636 · DOI	Laboratory research cells	Human oral (KB) epithelial cells exposed to orange juice fractions	Orange juice fractions and single volatile compounds (limonene, linalool, alpha-terpineol) Juice fractions and isolated compounds Not given in the abstract Cell assays · vs Untreated cells	Whole orange juice raised IL-6 formation by 23%. Of the volatile compounds found in the juice distillate, limonene stimulated IL-6, alpha-terpineol inhibited it and linalool had no effect. Alpha-terpineol also reduced expression of the IL-6 receptor gene. Alpha-terpineol lowered an inflammation signal (IL-6) in mouth cells in a dish Methods, limits and funding Outcomes: Intracellular interleukin-6 (IL-6) and IL-6 receptor gene expression Limitations: Cells only. The amounts were those of juice distillates in a dish, not drinking juice. Funding and conflicts: Not stated in the abstract. Read: abstract
Ibrahim 2019 Analysis of Terpenes in Cannabis sativa L. Using GC/MS: Method Development, Validation, and Application. Planta Med · PMID 30646402 · DOI	Chemical analysis plant material	Cannabis sativa plant material (University of Mississippi biomass and confiscated marijuana)	Validated GC-MS method for ten terpenes including alpha-terpineol Cannabis plant material	The method measures alpha-pinene, beta-pinene, beta-myrcene, limonene, terpinolene, linalool, alpha-terpineol, beta-caryophyllene, alpha-humulene and caryophyllene oxide. Average recoveries were 95.0 to 105.7% except terpinolene (67-70%). Detection and quantification limits were 0.25 and 0.75 micrograms/mL. Alpha-terpineol is one of ten terpenes that can be measured accurately in cannabis Methods, limits and funding Outcomes: Method validation for terpene measurement Limitations: A method paper; the abstract gives no alpha-terpineol amounts. Funding and conflicts: No conflict of interest declared. Read: abstract
Ibrahim 2023 Quantitative Determination of Cannabis Terpenes Using Gas Chromatography-Flame Ionization Detector. Cannabis Cannabinoid Res · PMID 36322895 · DOI	Chemical analysis plant material	Three main cannabis chemovars	Validated GC-FID method for ten terpenes including alpha-terpineol Cannabis biomass	The method measures ten major terpenes including alpha-terpineol with limits of detection and quantification of 0.3 and 1.0 micrograms/mL and recoveries of 89% to 111%. Alpha-terpineol is one of ten terpenes in a validated cannabis testing method Methods, limits and funding Outcomes: Method validation for terpene measurement Limitations: A method paper; no amounts. Funding and conflicts: No competing financial interests. Read: abstract
Jenkins 2023 Evaluating Potential Anxiolytic Effects of Minor Cannabinoids and Terpenes After Acute and Chronic Oral Administration in Rats. Cannabis Cannabinoid Res · PMID 37721993 · DOI	Animal research rat	Adult male Sprague Dawley rats (7 to 8 per group)	Alpha-terpineol 10 mg/kg by mouth (also D-limonene, alpha-pinene, bisabolol, beta-caryophyllene and minor cannabinoids) Isolated compounds in MCT oil Alpha-terpineol 10 mg/kg Single dose tested 30 minutes later · vs MCT oil vehicle; ethanol as an active comparison	In the abstract, bisabolol and D-limonene raised food intake and bisabolol, D-limonene, alpha-pinene and beta-caryophyllene decreased time in the outer zone in the novelty test, which suggests less anxiety. Alpha-terpineol is not named among the terpenes with an effect. The abstract says the terpenes did not impair or stimulate general movement. No anxiety-related effect of alpha-terpineol is named in the abstract Methods, limits and funding Outcomes: Marble burying, social interaction, novelty-induced hypophagia, motor activity Limitations: Only the abstract was read, which names no alpha-terpineol result; a null result in the full paper cannot be confirmed. One dose, one species, males only, short test. Funding and conflicts: Not stated in the abstract. Read: abstract
Jin 2021 Identification of Chemotypic Markers in Three Chemotype Categories of Cannabis Using Secondary Metabolites Profiled in Inflorescences, Leaves, Stem Bark, and Roots. Front Plant Sci · PMID 34276749 · DOI	Chemical analysis plant material	21 cannabis varieties grouped as THC-dominant, intermediate and CBD-dominant	Chemical profiling of inflorescences, leaves, stem bark and roots Cannabis plant parts	THC-dominant varieties had higher amounts of camphene, limonene, ocimene, sabinene hydrate, terpinolene, linalool, fenchol, alpha-terpineol, beta-caryophyllene, trans-beta-farnesene, alpha-humulene, trans-nerolidol and other compounds than CBD-dominant ones; intermediate varieties were in between. Alpha-terpineol was higher in THC-dominant than in CBD-dominant varieties in this study Methods, limits and funding Outcomes: Chemical markers of cannabis chemotypes Limitations: 21 varieties; the abstract gives no amounts. Two authors are employed by companies. Funding and conflicts: Two authors were employed by PBG BioPharma Inc.; one by Egret Bioscience and Lighthouse Genomics; the study reports no commercial conflict. Read: abstract
Jin 2024 Effectively α-Terpineol Suppresses Glioblastoma Aggressive Behavior and Downregulates KDELC2 Expression. Phytomedicine · PMID 38452695 · DOI	Laboratory research cells and mouse	Human glioblastoma cell lines, and an orthotopic glioblastoma mouse model	Alpha-terpineol (a monoterpenoid alcohol derived from Eucalyptus globulus and Pinus merkusii) Isolated compound Not given in the abstract Cell assays and a mouse model · vs Untreated cells and animals	Alpha-terpineol reduced glioblastoma growth, migration, invasion, blood-vessel formation and temozolomide resistance in the lab. It lowered KDELC2 and the Notch and PI3K/mTOR/MAPK pathways. In the mouse model it reached the brain, slowed tumour growth, and showed reduced cytotoxicity to vital organs, according to the authors. Slowed glioblastoma cells in dishes and in a mouse model Methods, limits and funding Outcomes: Glioblastoma growth, spread, new blood vessels, stem-cell traits, temozolomide resistance, KDELC2 and signalling pathways Limitations: Cells and mice. The authors call it a 'promising alternative therapeutic option', which a lab and mouse study cannot support. Not a treatment. Funding and conflicts: The authors declare no conflict of interest. Read: abstract
Li 2006 Analysis of volatile compounds emitted from fresh Syringa oblata flowers in different florescence by headspace solid-phase microextraction-gas chromatography-mass spectrometry. Anal Chim Acta · PMID 17723612 · DOI	Chemical analysis plant volatiles	Fresh flowers of Syringa oblata (a lilac species)	Headspace volatiles by SPME and GC-MS Flowers	Alpha-terpineol is listed among the most abundant volatiles from fresh flowers of S. oblata var. alba, along with lilac aldehydes and lilac alcohols, alpha-pinene, sabinene, beta-pinene, myrcene, d-limonene, eucalyptol, linalool, terpinolene and others. The abstract does not give percentages. Alpha-terpineol is one of the many scent compounds of one lilac species Methods, limits and funding Outcomes: Scent compounds released by the flowers Limitations: No amounts in the abstract; one lilac species. Funding and conflicts: Not stated in the abstract. Read: abstract
Lota 2002 Volatile components of peel and leaf oils of lemon and lime species. J Agric Food Chem · PMID 11829647 · DOI	Chemical analysis plant oil	Peel and leaf oils of 43 lemon and lime taxa	Essential oils by GC, GC-MS and 13C NMR Citrus peel and leaf	One of the two lemon leaf oil chemotypes was described as linalool / linalyl acetate / alpha-terpineol. The lime peel and lime leaf chemotypes in the abstract are built around limonene, beta-pinene, gamma-terpinene, geranial, neral, linalool, citronellal and sabinene; alpha-terpineol is not named for lime. Alpha-terpineol is named for one lemon leaf oil type, not for lime Methods, limits and funding Outcomes: Chemical variability (chemotypes) Limitations: Abstract only; amounts are not given. Funding and conflicts: Not stated in the abstract. Read: abstract
Negreiros 2021 Alpha-Terpineol as Antitumor Candidate in Pre-Clinical Studies. Anticancer Agents Med Chem · PMID 33397274 · DOI	Laboratory research cells	Murine sarcoma 180 cells taken from mouse abdominal fluid	Alpha-terpineol at 100, 250 and 500 micrograms/mL Isolated compound 100, 250, 500 micrograms/mL Cell assays · vs Doxorubicin and cisplatin as positive controls	Cell viability fell to 50.9%, 38.53% and 30.82% at 100, 250 and 500 micrograms/mL. Alpha-terpineol damaged DNA (more DNA fragmentation, micronuclei, nucleoplasmic bridges and nuclear buds) and the pattern fitted early, late and necrotic cell death. Killed mouse tumour cells in a dish and damaged their DNA Methods, limits and funding Outcomes: Cell viability, DNA damage, micronuclei, DNA fragmentation, cell death Limitations: Cells only. The DNA damage that kills tumour cells is also a safety signal to keep in mind; the abstract does not test normal cells. Funding and conflicts: Not stated in the abstract. Read: abstract
Nogueira 2014 Terpinen-4-ol and alpha-terpineol (tea tree oil components) inhibit the production of IL-1β, IL-6 and IL-10 on human macrophages. Inflamm Res · PMID 24947163 · DOI	Laboratory research cells	Human monocyte-derived (U937) macrophages stimulated with bacterial lipopolysaccharide	Tea tree oil, terpinen-4-ol and alpha-terpineol Isolated compounds and an essential oil Not given in the abstract Cell assays · vs Untreated stimulated cells	Tea tree oil and both components significantly reduced IL-1 beta, IL-6 and IL-10 production. TNF-alpha was not affected. The results section says the cytokine changes were not explained by changes in NF-kappaB or p38 MAPK activation, while the conclusion mentions interference with the NF-kappaB, p38 or ERK MAPK pathways. Lower IL-1 beta, IL-6 and IL-10 in stimulated human macrophages Methods, limits and funding Outcomes: Cytokines TNF-alpha, IL-1 beta, IL-6 and IL-10; NF-kappaB and p38 MAPK activation Limitations: Cells only. The abstract is inconsistent about the pathway, so only the cytokine result is used. Funding and conflicts: Not stated in the abstract. Read: abstract
Odieka 2026 Chemical Characterization and Biological Potential of the Essential Oils from the Flowers of Two Cannabis sativa L. Cultivars from Komga, South Africa. Molecules · PMID 42280118 · DOI	Chemical analysis plant oil	Flower essential oils from two cannabis cultivars (Lifter and Cherrywine) grown in South Africa	Hydro-distilled oils analysed by GC-MS Fresh and dried cannabis flowers	Eighteen compounds were found in the oils of both cultivars, including terpineol (0.14-1.38%) and alpha-terpineol (0.19-0.75%). The main ones were caryophyllene (10.71-19.96%), beta-pinene (1.37-13.21%) and humulene (5.88-9.77%). Antioxidant and anti-inflammatory lab tests were weak or limited by variability. Alpha-terpineol was 0.19 to 0.75% of the flower oil in two South African cultivars Methods, limits and funding Outcomes: Chemical composition and in vitro antioxidant and anti-inflammatory tests Limitations: Percentages are of steam-distilled oil, not of flower weight, and cannot be compared with mg/g flower values. Two cultivars only. Funding and conflicts: No conflicts of interest declared. Read: abstract
Park 2012 Antimicrobial effect of linalool and α-terpineol against periodontopathic and cariogenic bacteria. Anaerobe · PMID 22537719 · DOI	Laboratory research bacteria in vitro	Cultures of periodontopathic and cariogenic (gum-disease and tooth-decay) bacteria	Linalool and alpha-terpineol Isolated compounds The authors advise staying below 0.4 mg/mL for toothpaste or mouthwash use Lab culture · vs Untreated bacteria	Linalool and alpha-terpineol showed strong antimicrobial activity against the gum-disease and tooth-decay bacteria tested. The authors say their concentration should be kept below 0.4 mg/mL if used in toothpaste or gargles and that other antimicrobial compounds should be combined with them. Killed or slowed mouth bacteria in dishes Methods, limits and funding Outcomes: Antibacterial activity Limitations: Only the short conclusion section was visible in the abstract. Lab cultures; no person was treated. Funding and conflicts: Not stated in the abstract. Read: abstract
Paulino 2022 Alpha-terpineol prevents myocardial damage against isoproterenol-MI induced in Wistar-Kyoto rats: new possible to promote cardiovascular integrity. Life Sci · PMID 34740575 · DOI	Animal research rat	Wistar and Wistar-Kyoto rats given isoproterenol to cause heart damage	Alpha-terpineol by mouth at 25, 50 and 75 mg/kg Isolated compound 25, 50, 75 mg/kg by mouth 15 days, with isoproterenol on days 14 and 15 · vs Control groups	Isoproterenol caused higher death, raised heart-damage enzymes, fast heart rate, tissue death and larger infarcts. Pre-treatment with alpha-terpineol significantly reduced these effects, and tissue findings agreed with the blood tests. The abstract says the Protium heptaphyllum resin, a plant source of alpha-terpineol, is used in Brazilian indigenous medicine for heart disease. Less heart damage in rats given a heart-stressing drug Methods, limits and funding Outcomes: Death rate, heart marker enzymes, ECG, heart rate, tissue damage, infarct size Limitations: Rats, pre-treatment before a drug-induced heart injury. Not a model of the heart disease people have. Not evidence for people. Funding and conflicts: Not stated in the abstract. Read: abstract
Quintans-Júnior 2011 α-Terpineol reduces nociceptive behavior in mice. Pharm Biol · PMID 21385090 · DOI	Animal research mouse	Mice	Alpha-terpineol (TPN) Isolated compound Doses and route not given in the abstract Acute tests · vs Vehicle	Alpha-terpineol significantly reduced paw licking in both phases of the formalin test and reduced writhing. In the glutamate test all doses protected, and in the capsaicin test it reduced pain behaviour in a dose-related way. The hot-plate test suggested a central (brain and spinal cord) effect. The authors say the results were unlikely to be caused by movement problems. Less pain behaviour in several mouse pain tests Methods, limits and funding Outcomes: Pain behaviour in acetic acid writhing, formalin, glutamate and capsaicin tests; hot-plate test; motor function Limitations: Mice only, acute pain tests. The abstract gives neither the doses nor the route. Does not show pain relief in people. Funding and conflicts: Not stated in the abstract. Read: abstract
Raz 2026 Synergistic and additive terpene-THC interactions in cannabinoid CB1 and CB2 receptors. Biochem Pharmacol · PMID 42349621 · DOI	Laboratory research cells	Xenopus laevis frog egg cells (oocytes) carrying human CB1 or CB2 receptors and GIRK channels	THC with individual cannabis terpenes (including terpineol) and terpene mixtures Isolated compounds Concentration-response curves Electrical recordings · vs THC alone	Several terpenes boosted THC activation of CB1 and CB2. The abstract names terpineol (isomer not stated) among those that synergised with THC at CB1 (with borneol, limonene, sabinene, alpha-pinene and ocimene). The authors suggest terpenes may act as weak partial agonists or allosteric modulators. In egg cells, terpineol added to THC's activation of the CB1 receptor more than expected Methods, limits and funding Outcomes: Receptor activation by THC alone or with terpenes (isobolographic analysis) Limitations: Frog egg cells expressing human receptors, not people. The study team includes employees of a medical cannabis maker (Bazelet). Says nothing about how cannabis feels or about safety. Funding and conflicts: Three authors are employees of the Bazelet group, a medical cannabis manufacturer in Israel; the others report no competing interests. Read: abstract
Rong 2024 Reprogramming of arachidonic acid metabolism using α-terpineol to alleviate asthma: insights from metabolomics. Food Funct · PMID 38526853 · DOI	Animal research mouse	Mice with ovalbumin-induced asthma	Alpha-terpineol before challenge Isolated compound Dose not given in the abstract Treatment around a one-week challenge · vs Control and model groups	Treated mice had fewer white cells and lower inflammatory cytokines in airway fluid, less inflammation around the airways, less goblet-cell overgrowth and mucus, and less Muc5ac. Metabolite tests pointed to arachidonic acid handling: lower arachidonic acid, less 5-lipoxygenase and fewer cysteinyl leukotrienes in lung tissue. Less airway inflammation and mucus in asthmatic mice Methods, limits and funding Outcomes: White cells and cytokines in airway fluid, lung tissue changes, mucus, lung and blood metabolites Limitations: Mice. Pre-treatment, not treatment of established asthma. Not evidence for people. Funding and conflicts: Not stated in the abstract. Read: abstract
Safaripour 2018 Role of l-arginine/SNAP/NO/cGMP/K(ATP) channel signalling pathway in antinociceptive effect of α-terpineol in mice. J Pharm Pharmacol · PMID 29380385 · DOI	Animal research mouse	Male NMRI mice	Alpha-terpineol 40 and 80 mg/kg given into the abdomen, with blockers and boosters of the nitric oxide pathway Isolated compound 40 and 80 mg/kg i.p. Single doses, formalin test over 30 minutes · vs Vehicle	Alpha-terpineol produced dose-dependent pain relief in both phases of the formalin test. L-NAME (a nitric oxide synthase blocker) reduced the effect, L-arginine increased it in the second phase, methylene blue reduced it, and glibenclamide (a potassium-channel blocker) significantly reversed it. The authors conclude the effect runs through the L-arginine / nitric oxide / cGMP / KATP channel pathway. Pain relief in mice that depended on the nitric oxide pathway and potassium channels Methods, limits and funding Outcomes: Pain responses in the formalin test Limitations: Mice, injected doses, one pain test. Mechanism inferred from blockers. Funding and conflicts: Not stated in the abstract. Read: abstract
Satyal 2013 Volatile constituents of Pinus roxburghii from Nepal. Pharmacognosy Res · PMID 23598924 · DOI	Chemical analysis plant oil	Cone, needle and bark oils of Pinus roxburghii from Nepal	Essential oils by hydrodistillation, GC-MS Pine cone, needle and bark	The three oils were dominated by sesquiterpenes (E-caryophyllene 26.8-34.5%; alpha-humulene 5.0-7.3%) and by the monoterpene alcohols terpinen-4-ol (4.1-30.1%) and alpha-terpineol (2.8-5.0%). The abstract says the cone oil killed MCF-7 cancer cells in the lab and was active against one fungus, and that the oil is traditionally used for cuts, wounds, boils and blisters. A pine oil with 2.8 to 5.0% alpha-terpineol Methods, limits and funding Outcomes: Chemical composition and lab activity Limitations: One pine species from one place; pine oils differ widely. Funding and conflicts: Conflict of interest: none declared. Read: abstract
Shipton 1984 Dettol (chloroxylenol and terpineol) poisoning in a pregnant patient. A case report. S Afr Med J · PMID 6505887	Case report	1 A 30-year-old woman, 28 weeks pregnant, who swallowed 300 ml of Dettol on purpose	Dettol, a household disinfectant sold as containing chloroxylenol and terpineol Commercial disinfectant mixture 300 ml swallowed Single event	The abstract only says that she was admitted after deliberately swallowing 300 ml of Dettol and that her management and the management of Dettol overdose are discussed. It does not give the outcome. Hospital admission after a large swallowed amount of a disinfectant that contains terpineol among other ingredients Methods, limits and funding Outcomes: Hospital management of a Dettol overdose Limitations: A one-paragraph abstract with no outcome. The product is a mixture (the title names chloroxylenol and terpineol), so nothing here can be blamed on terpineol alone. A second report (British Medical Journal 1978, PubMed 638509) is titled 'Severe Dettol (chloroxylenol and terpineol) poisoning' but has no abstract and was not read. Funding and conflicts: Not stated in the abstract. Read: abstract
Souza 2011 Gastroprotective activity of α-terpineol in two experimental models of gastric ulcer in rats. Daru · PMID 22615669	Animal research rat	Rats	Alpha-terpineol by mouth at 10, 30 and 50 mg/kg, before ulcer-causing agents Isolated compound 10, 30, 50 mg/kg by mouth Single doses one hour before the challenge · vs Vehicle	Alpha-terpineol protected against ethanol-induced stomach ulcers at 10, 30 and 50 mg/kg. Pre-treatment with indomethacin did not block the protection, and alpha-terpineol did not change gastric secretion in pylorus-ligated rats. The authors conclude the protection involves neither extra prostaglandins nor less acid. (The abstract's text on the indomethacin ulcer model mentions another compound, epoxy-carvone, so that result is not used here.) Fewer ethanol-induced stomach ulcers in rats Methods, limits and funding Outcomes: Stomach ulcer scores after ethanol and indomethacin; gastric acid and volume in pylorus-ligated rats Limitations: Rats; the indomethacin-ulcer result in the abstract is unclear and was not used. Not evidence for heartburn or ulcers in people. Funding and conflicts: Not stated in the abstract. Read: abstract
Su 2018 Safety and efficacy of 4-terpineol against microorganisms associated with blepharitis and common ocular diseases. BMJ Open Ophthalmol · PMID 30123842 · DOI	Mixed human patch test and lab human and in vitro	Human volunteers (repeated insult patch test) plus laboratory microbe tests; number of volunteers not given in the abstract	2% 4-terpineol (terpinen-4-ol) foam formulation. THIS IS A DIFFERENT MOLECULE FROM ALPHA-TERPINEOL. Isolated compound in a foam 2% in the foam Patch test and 14-28 day lab tests · vs Standard lab methods	The 2% terpinen-4-ol foam did not cause eye irritation, skin irritation, sensitisation or allergic contact dermatitis in the human patch test. It met the United States Pharmacopeia antimicrobial test and killed 13 bacteria, 1 fungus and Acanthamoeba castellanii within 60 seconds in the lab. The authors say clinical efficacy in eye disease was not studied. No skin or eye reaction to a 2% terpinen-4-ol foam in the patch test; strong germ-killing in the dish Methods, limits and funding Outcomes: Antimicrobial effectiveness; skin and eye irritation; skin sensitisation Limitations: A different molecule (terpinen-4-ol), a 2% foam, number of volunteers not given in the abstract. The senior author is an inventor and shareholder of the company and holds patents on tea tree oil ingredients for eyelid mites. Funding and conflicts: Competing interests: the senior author is an inventor, shareholder and employee of TissueTech, Inc. and has filed patents on tea tree oil and its ingredients for treating demodecosis. Read: abstract
US Food and Drug Administration 2026 US Code of Federal Regulations Title 21, section 172.515: Synthetic flavoring substances and adjuvants eCFR (API; text version dated 2026-10-01, retrieved 2026-10-25) · Source	Authoritative guidance n/a	n/a	n/a	Section 172.515 says that synthetic flavouring substances and adjuvants may be safely used in food under the stated conditions, including use in the minimum quantity required for the intended effect and following good manufacturing practice. The list includes 'alpha-Terpineol; p-menth-1-en-8-ol' and 'beta-Terpineol'. gamma-Terpineol does not appear on the list. Section 172.515 says that synthetic flavouring substances and adjuvants may be safely used in food under the stated conditions, including use in the minimum quantity required for the intended effect and following good manufacturing practice. The list includes 'alpha-Terpineol; p-menth-1-en-8-ol' and 'beta-Terpineol'. gamma-Terpineol does not appear on the list. Methods, limits and funding Outcomes: Whether alpha-terpineol is on the FDA's list of synthetic flavouring substances allowed in food Limitations: A food-flavouring rule. It says nothing about inhaling, vaping or heating terpineol, supplements, or use in cannabis products. Funding and conflicts: n/a Read: full-text
US National Library of Medicine (PubChem) 2026 PubChem: GHS classification for alpha-terpineol (aggregated from company notifications to the ECHA C&L Inventory) PubChem PUG-View API (retrieved 2026-10-25) · Source	Authoritative guidance n/a	n/a	n/a	In the main aggregate (2,747 reports from 16 notifications): causes skin irritation (H315, 98.9%) and causes serious eye irritation (H319, 81.8%); 1.1% of reports said the chemical does not meet GHS hazard criteria. PubChem notes that classifications vary between notifications. No sensitiser class is shown above its 10% display threshold. In the main aggregate (2,747 reports from 16 notifications): causes skin irritation (H315, 98.9%) and causes serious eye irritation (H319, 81.8%); 1.1% of reports said the chemical does not meet GHS hazard criteria. PubChem notes that classifications vary between notifications. No sensitiser class is shown above its 10% display threshold. Methods, limits and funding Outcomes: Hazard classes that companies notify for the pure chemical Limitations: Company-notified classifications for the pure chemical, not a regulator's ruling, and not about scent or low-level food exposure. Funding and conflicts: n/a Read: full-text
US National Library of Medicine (PubChem) 2026 PubChem: alpha-Terpineol (CID 17100), with compound records for the (R)-(+) form (CID 442501), the (S)-(-) form (CID 443162), beta-terpineol (CID 8748), gamma-terpineol (CID 11467) and terpinen-4-ol (CID 11230) PubChem REST API (retrieved 2026-10-25) · Source	Authoritative guidance n/a	n/a	n/a	CID 17100: C10H18O, molecular weight 154.25, IUPAC name 2-(4-methylcyclohex-3-en-1-yl)propan-2-ol, CAS 98-55-5 (with 8006-39-1 and other numbers also listed as synonyms). CID 442501 is the (R)-(+) form, 2-[(1R)-4-methylcyclohex-3-en-1-yl]propan-2-ol; CID 443162 the (S)-(-) form. Beta-terpineol (CID 8748) is 1-methyl-4-prop-1-en-2-ylcyclohexan-1-ol; gamma-terpineol (CID 11467) is 1-methyl-4-propan-2-ylidenecyclohexan-1-ol; terpinen-4-ol (CID 11230) is 4-methyl-1-propan-2-ylcyclohex-3-en-1-ol. All have the formula C10H18O. CID 17100: C10H18O, molecular weight 154.25, IUPAC name 2-(4-methylcyclohex-3-en-1-yl)propan-2-ol, CAS 98-55-5 (with 8006-39-1 and other numbers also listed as synonyms). CID 442501 is the (R)-(+) form, 2-[(1R)-4-methylcyclohex-3-en-1-yl]propan-2-ol; CID 443162 the (S)-(-) form. Beta-terpineol (CID 8748) is 1-methyl-4-prop-1-en-2-ylcyclohexan-1-ol; gamma-terpineol (CID 11467) is 1-methyl-4-propan-2-ylidenecyclohexan-1-ol; terpinen-4-ol (CID 11230) is 4-methyl-1-propan-2-ylcyclohex-3-en-1-ol. All have the formula C10H18O. Methods, limits and funding Outcomes: Chemical identity of the terpineol isomers Limitations: Database records; they identify the molecules but say nothing about effects. Funding and conflicts: n/a Read: full-text
Vázquez 2023 HPTLC Analysis and Chemical Composition of Selected Melaleuca Essential Oils. Molecules · PMID 37175338 · DOI	Chemical analysis plant oil	Seven tea tree oils (Melaleuca alternifolia) and four other Melaleuca oils	Essential oils analysed by GC-MS and HPTLC Essential oil	Among the seven tea tree oils, terpinen-4-ol (37.66-44.28%), gamma-terpinene (16.42-20.75%), alpha-terpinene (3.47-12.62%), alpha-terpineol (3.11-4.66%) and terpinolene (2.75-4.19%) were the most abundant. In the cajuput (M. cajuputi) oil tested, 1,8-cineole was 64.63%; the abstract does not give alpha-terpineol for it. Tea tree oil contains about 3 to 5% alpha-terpineol Methods, limits and funding Outcomes: Chemical composition Limitations: Seven tea tree oils from one study. Composition varies by batch. Funding and conflicts: No conflict of interest. Mention of a proprietary product does not imply endorsement by the US Department of Agriculture. Read: abstract
Wang 2024 Efficacy of Terpinen-4-ol Combined With Eyelid Deep Cleaning for the Treatment of Demodex Blepharitis: A Randomized, Open-Label Trial. Transl Vis Sci Technol · PMID 39560630 · DOI	Controlled trial	40 Adults with Demodex blepharitis (eyelid mite infection) at one eye clinic in China	Terpinen-4-ol (T4O) cleaning wipes alone, or T4O wipes plus deep eyelid cleaning. THIS IS TERPINEN-4-OL, A DIFFERENT MOLECULE FROM ALPHA-TERPINEOL. Isolated compound in a wipe Not given in the abstract 2 months of treatment, 1 month of follow-up · vs The two arms were compared with each other; no placebo group	Both groups had fewer mites after two months (reductions of 5.65 and 7.75 mites). Mite counts rose again one month after the wipes alone were stopped, while the combination group held its gain (8.70 versus 4.15 at month three, P = 0.043). Only the combination group had a significant OSDI improvement at months two and three. No adverse events were reported. Fewer eyelid mites during treatment, with rebound when wipes alone were stopped Methods, limits and funding Outcomes: Demodex mite counts, Ocular Surface Disease Index (OSDI), eyelid margin signs, corneal staining Limitations: Terpinen-4-ol, not terpineol. Open-label (people knew the treatment), 40 people, no placebo group, one clinic. It says nothing about alpha-terpineol. Funding and conflicts: No conflict of interest declared in the abstract. Read: abstract
Wang 2025 Effects of a cannabidiol/terpene formulation on sleep in individuals with insomnia: a double-blind, placebo-controlled, randomized, crossover study. J Clin Sleep Med · PMID 39167421 · DOI	Controlled trial	125 Adults with insomnia	Oral CBD (300 mg) plus eight terpenes at 1 mg each (linalool, myrcene, phytol, limonene, alpha-terpinene, alpha-terpineol, alpha-pinene, beta-caryophyllene); no THC Isolated compounds in one formulation CBD 300 mg and 1 mg of each terpene, at least 4 days a week 4 weeks, crossover design · vs Placebo	The CBD-terpene regimen raised the average share of the night in slow-wave plus REM sleep by 1.3% (standard error 0.60%; 95% CI 0.1 to 2.5%; P = .03) compared with placebo. Gains were larger in people with low baseline slow-wave plus REM sleep and in day sleepers. Total sleep time, resting heart rate and heart rate variability did not change. No adverse events were reported. A small average gain in slow-wave plus REM sleep from a CBD-plus-eight-terpene mixture Methods, limits and funding Outcomes: Percentage of the night in slow-wave plus REM sleep, measured by a wrist-worn tracker Limitations: The effect cannot be assigned to alpha-terpineol: it was one of eight terpenes taken with 300 mg of CBD. The average gain was marginal (lower confidence limit 0.1%), sleep was measured by a wrist device, and the authors chose the terpene mixture. Funding and conflicts: Funded by Defined Research, Inc. Most authors hold equity in that company, and two more are consultants with stock options (stated in the paper). Read: abstract
Wu 2014 γ-terpineol inhibits cell growth and induces apoptosis in human liver cancer BEL-7402 cells in vitro. Int J Clin Exp Pathol · PMID 25400730	Laboratory research cells	Human liver cancer (BEL-7402) cells	GAMMA-terpineol (a different isomer from alpha-terpineol) Isolated compound 40 to 640 micrograms/mL 48 hours · vs Untreated cells	Gamma-terpineol slowed liver cancer cell growth in a dose-dependent way, produced signs of programmed cell death, blocked cells in the G1 or S phase and produced a typical 'DNA ladder' at 320 micrograms/mL. Slowed liver cancer cells in dishes Methods, limits and funding Outcomes: Cell growth, colony formation, cell death, cell cycle Limitations: This paper is about GAMMA-terpineol, not alpha-terpineol. Cells only. Funding and conflicts: Not stated in the abstract. Read: abstract
Yang 2025 Restoring colistin sensitivity in colistin-resistant gram-negative bacteria: combinatorial use of α-terpineol and colistin. Microbiol Spectr · PMID 41025831 · DOI	Laboratory research bacteria in vitro	Colistin-resistant Gram-negative bacteria in culture	Alpha-terpineol combined with colistin Isolated compound Concentrations not given in the abstract Lab assays (checkerboard, time-kill, biofilm) · vs Colistin alone	The combination was strongly synergistic against colistin-resistant bacteria in vitro, stopped biofilm formation and cleared established biofilms. Scanning electron microscopy showed the bacterial membranes were badly disrupted after six hours of the combined treatment. The authors say alpha-terpineol kept a degree of safety at the synergistic concentrations in cell toxicity and red blood cell haemolysis tests. Restored colistin's effect on resistant bacteria in the lab Methods, limits and funding Outcomes: Synergy with colistin, biofilm, membrane damage, cell and red blood cell safety Limitations: Lab only. Not an infection treatment. Do not use terpineol with antibiotics. Funding and conflicts: The authors declare no conflict of interest. Read: abstract
da Silva 2016 α-Terpineol Induces Gastric Retention of Liquids by Inhibiting Vagal Parasympathetic Pathways in Rats. Planta Med · PMID 27124242 · DOI	Animal research rat and tissue	Awake rats, and isolated stomach muscle strips	Alpha-terpineol by gavage 50 mg/kg; 1 to 2000 micromolar on muscle strips Isolated compound 50 mg/kg by gavage Single doses · vs Vehicle	Alpha-terpineol delayed gastric emptying of a liquid meal 10 minutes after eating. Atropine and L-NAME removed the delay, and it did not occur in rats with the vagus nerve cut, so intact vagal nerve signalling was needed. On isolated stomach strips it relaxed contractions in a concentration-dependent way and inhibited contractions from electrical stimulation. Slower stomach emptying in rats, through the vagus nerve Methods, limits and funding Outcomes: Gastric emptying of a liquid meal; muscle relaxation Limitations: Rats and isolated tissue. A slower-emptying effect could matter for how fast oral medicines or food leave the stomach, but nothing in people was tested. Funding and conflicts: Not stated in the abstract. Read: abstract
de Groot 2016 Tea tree oil: contact allergy and chemical composition. Contact Dermatitis · PMID 27173437 · DOI	Review	Review of case reports and patch-test series of tea tree oil	Tea tree oil (Melaleuca alternifolia) and its components Essential oil	Of all essential oils, tea tree oil has caused most published allergic reactions since 1991. In routine patch testing, 0.1% to 3.5% of tested people reacted. The major constituents include terpinen-4-ol, gamma-terpinene, 1,8-cineole, alpha-terpinene, alpha-terpineol, p-cymene and alpha-pinene. Fresh oil is a weak to moderate sensitiser and oxidation raises its potency. The major sensitisers appear to be ascaridole, terpinolene, alpha-terpinene, 1,2,4-trihydroxymenthane, alpha-phellandrene and limonene; alpha-terpineol is not on that list. Tea tree oil, which contains some alpha-terpineol, is a recognised skin allergen; alpha-terpineol is not named as a main culprit Methods, limits and funding Outcomes: Contact allergy to tea tree oil and its chemistry Limitations: A review of tea tree oil, not of alpha-terpineol on its own. Funding and conflicts: Not stated in the abstract. Read: abstract
de Oliveira 2012 α-terpineol reduces mechanical hypernociception and inflammatory response. Basic Clin Pharmacol Toxicol · PMID 22380944 · DOI	Animal research mouse and cell	Mice, plus mouse macrophage cells	Alpha-terpineol (TPN) 25, 50 or 100 mg/kg by injection into the abdomen; 1, 10 and 100 micrograms/mL on cells Isolated compound 25-100 mg/kg i.p. Acute tests · vs Vehicle	Pre-treatment with alpha-terpineol inhibited the development of pain hypersensitivity caused by carrageenan or TNF-alpha, and similar effects were seen with PGE2 and dopamine. It significantly reduced white-cell (neutrophil) influx in a pleurisy model. At 1, 10 and 100 micrograms/mL it reduced nitrite production by stimulated mouse macrophages (p < 0.01). Less inflammatory pain sensitivity and less white-cell influx in mice; less nitrite in cultured cells Methods, limits and funding Outcomes: Mechanical pain sensitivity after carrageenan, TNF-alpha, PGE2 or dopamine; neutrophil influx in pleurisy; nitrite production by macrophages Limitations: Mice and cells; injected doses are far from what anyone would breathe from cannabis or a scent. Not evidence for people. Funding and conflicts: Not stated in the abstract. Read: abstract

What we do not know yet

What the evidence supports: everything is very-low or insufficient certainty. It is almost all from cells and animals.
No human trial of alpha-terpineol alone for any use, and no human safety study; the one human trial that included it was a company-funded mixture.
The mouse and rat doses were milligrams per kilogram, far above what a scent or cannabis flower gives; whether small amounts do anything is unknown.
The rat birth-defect study has not been repeated, and pregnancy and breastfeeding have no human data.
No data on how the human body absorbs and breaks it down, or on interactions with medicines.
The findings of the fragrance industry's safety assessments could not be read, and regulatory documents beyond FDA and EFSA were not read.

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 can change what this page says.

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".

Other 12

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Pain behaviour in mice (paw licking, writhing, touch and heat sensitivity)

Lowered in trials

How much an animal licks, writhes, withdraws or avoids when a painful stimulus is given.

Very low certainty

Results and what it means

Why it was measured

It is the usual way to see whether a compound might work against pain before any human study.

Statistical vs. clinical meaning

Consistent direction across four mouse studies; all animal.

Safety implication

None reported in these mouse studies.

Study	Result	People	Product
²³	Less paw licking in both phases of the formalin test and less writhing; dose-related effect in the capsaicin test; central effect in the hot-plate test.	Mice	Alpha-terpineol, doses not given in the abstract
³	Dose-related reversal of mechanical allodynia and thermal hyperalgesia in nerve-injured mice; less potent without CB1 (2.91-fold) or CB2 (11.73-fold) receptors.	Mice with sciatic nerve injury	Alpha-terpineol, beta-caryophyllene or gamma-terpinene
⁷	Less mechanical pain sensitivity and spontaneous pain behaviour in mice with a tumour.	Mice with sarcoma 180	Alpha-terpineol

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iNOS protein in mouse tumours

Lowered in trials

iNOS is an enzyme that makes nitric oxide during inflammation and is linked to pain signalling in tumours.

Very low certainty

Results and what it means

Why it was measured

Lower iNOS was a possible explanation for the pain effect.

Statistical vs. clinical meaning

One mouse study.

Safety implication

No toxicity was evident in blood tests.

Study	Result	People	Product
⁷	Lower iNOS immunocontent in tumours; higher antioxidant capacity (FRAP) and glutathione.	Mice with sarcoma 180	Alpha-terpineol

⁷

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Share of the night in slow-wave plus REM sleep (wrist device)

Raised in trials

The proportion of the night spent in deep (slow-wave) and dreaming (REM) sleep, estimated by a wearable tracker.

Not enough evidence

Results and what it means

Why it was measured

It was the main measure in the insomnia trial.

Statistical vs. clinical meaning

Marginal gain from a mixture; cannot be assigned to alpha-terpineol. Wearable estimate, not a sleep-lab recording.

Safety implication

No adverse events were reported.

Study	Result	People	Product
³⁶	Up 1.3% on average (95% CI 0.1 to 2.5%; P = .03) with the CBD-plus-eight-terpene mixture compared with placebo; total sleep time unchanged.	125 adults with insomnia	300 mg CBD plus 1 mg each of eight terpenes including alpha-terpineol

³⁶

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THC activation of the CB1 receptor in egg cells

Raised in trials

How strongly THC switches on the CB1 receptor, measured by an electrical signal in cells.

Not enough evidence

Results and what it means

Why it was measured

To see whether a terpene changes THC's action at its main brain receptor.

Statistical vs. clinical meaning

Cell experiment; no effect in people shown.

Safety implication

Unknown.

Study	Result	People	Product
²⁴	Terpineol was among the terpenes that synergistically boosted THC activation at CB1.	Frog egg cells with human CB1	THC plus terpineol

²⁴

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Interleukin-6 (IL-6) and IL-1 beta in cells

Lowered in trials

Cytokines are signalling proteins that cells release during inflammation.

Very low certainty

Results and what it means

Why it was measured

A common lab measure of an anti-inflammatory effect.

Statistical vs. clinical meaning

Consistent in two cell studies; no human data.

Safety implication

Unknown.

Study	Result	People	Product
¹⁹	IL-1 beta, IL-6 and IL-10 fell with alpha-terpineol in stimulated human macrophages; TNF-alpha did not change.	U937 macrophages	Alpha-terpineol
¹⁰	Alpha-terpineol lowered IL-6 formation and IL-6 receptor gene expression in mouth cells.	KB oral cells	Alpha-terpineol

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White-cell (neutrophil) influx in mouse pleurisy

Lowered in trials

Neutrophils are white blood cells that rush to inflamed tissue.

Very low certainty

Results and what it means

Why it was measured

A standard measure of acute inflammation in animals.

Statistical vs. clinical meaning

Mouse study.

Safety implication

Unknown.

Study	Result	People	Product
⁴¹	Significant reduction in neutrophil influx; lower nitrite production in macrophages at 1 to 100 micrograms/mL.	Mice and mouse macrophages	Alpha-terpineol 25-100 mg/kg i.p.

⁴¹

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White cells and cytokines in airway fluid (mouse asthma)

Lowered in trials

Cells and signal proteins washed from the lungs of asthmatic mice.

Very low certainty

Results and what it means

Why it was measured

They show how much airway inflammation there is.

Statistical vs. clinical meaning

One mouse study.

Safety implication

Unknown.

Study	Result	People	Product
²⁵	Lower leukocyte count and cytokines in airway fluid; lower Muc5ac; less 5-lipoxygenase and cysteinyl leukotrienes in lung tissue.	Mice with ovalbumin asthma	Alpha-terpineol

²⁵

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Survival of tumour cells in a dish

Lowered in trials

The share of cells still alive after exposure.

Very low certainty

Results and what it means

Why it was measured

A first screen for anti-cancer activity.

Statistical vs. clinical meaning

Dish results only.

Safety implication

The DNA damage in tumour cells shows the molecule is not harmless to cells.

Study	Result	People	Product
¹⁸	Viability fell to 50.9%, 38.53% and 30.82% at 100, 250 and 500 micrograms/mL; DNA damage and cell death signs.	Mouse sarcoma 180 cells	Alpha-terpineol
⁸	Small cell lung carcinoma cells most sensitive; NF-kappaB activity fell.	Human tumour cell lines	Alpha-terpineol

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Stomach ulcer score in rats

Lowered in trials

How much damage appears on the stomach lining after a harmful challenge.

Very low certainty

Results and what it means

Why it was measured

A standard measure of stomach protection in animals.

Statistical vs. clinical meaning

Rat study.

Safety implication

Unknown.

Study	Result	People	Product
²⁹	Protection against ethanol-induced ulcers at 10, 30 and 50 mg/kg by mouth; gastric acid not changed.	Rats	Alpha-terpineol by mouth

²⁹

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Speed of stomach emptying in rats

Lowered in trials

How quickly a liquid meal leaves the stomach.

Very low certainty

Results and what it means

Why it was measured

Shows effects on gut movement and possible interactions with oral medicines.

Statistical vs. clinical meaning

Rat study; one dose.

Safety implication

Slower emptying could change timing of oral drugs; not tested in people.

Study	Result	People	Product
³⁹	50 mg/kg by gavage delayed emptying; needed an intact vagus nerve.	Awake rats	Alpha-terpineol by gavage

³⁹

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Heart damage markers and infarct size in rats

Lowered in trials

Blood enzymes released from damaged heart muscle and the size of dead heart tissue.

Very low certainty

Results and what it means

Why it was measured

Shows heart injury in animal models.

Statistical vs. clinical meaning

Drug-injury rat model.

Safety implication

Unknown.

Study	Result	People	Product
²²	Lower death rate, marker enzymes, tachycardia and infarct size in rats pre-treated with 25-75 mg/kg alpha-terpineol.	Rats given isoproterenol	Alpha-terpineol for 15 days

²²

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Demodex mite count on eyelashes (terpinen-4-ol, not terpineol)

Lowered in trials

The number of eyelid mites counted under a microscope.

Very low certainty

Results and what it means

Why it was measured

It is the main treatment measure for eyelid mite infection.

Statistical vs. clinical meaning

Different molecule; open-label trial.

Safety implication

No adverse events were reported.

Study	Result	People	Product
³⁵	Fewer mites after two months with terpinen-4-ol wipes; rebound after stopping wipes alone.	40 adults with Demodex blepharitis	Terpinen-4-ol wipes with or without deep cleaning

³⁵

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 5

Almost nothing is known about safety in people. No trial has tested alpha-terpineol on its own in people. The only human trial that included it gave 125 adults with insomnia 300 mg of CBD plus eight terpenes at 1 mg each for 4 weeks and reported no adverse events, but that cannot show what one ingredient does. Everything else is cell, animal or chemical-database information. Controlled trial ³⁶
Skin and eye irritation is the best-documented hazard. Companies that notify alpha-terpineol to the European chemicals inventory most often classify it as causing skin irritation (98.9% of 2,747 reports) and serious eye irritation (81.8%). These are classifications for the pure chemical. They do not tell us how likely irritation is from a scent, a food flavour or a cannabis flower. Authoritative guidance ³²
Skin allergy: no clear sign for alpha-terpineol itself, but oils that contain it can sensitise. In a rat screening test (the popliteal lymph node assay), terpineol did not trigger a response, and the authors found no monoterpene to be a true sensitiser. A review of tea tree oil, which contains some alpha-terpineol, says the oil is a weak to moderate sensitiser (more so when it has aged in air) and names other components, not alpha-terpineol, as the main culprits. EFSA calls whole cajuput oil, which is about 8% alpha-terpineol, a skin and eye irritant and a skin and breathing-tract sensitiser. The findings of an industry safety review of alpha-terpineol as a fragrance ingredient could not be read. Mixed ^{6 40 4 2}
Possible harm in pregnancy (rat study, not yet confirmed). A 2026 rat study found lower fetal weight and a range of skeletal malformations at 75, 150 and 300 mg/kg during the organ-forming period, with lower expression of the HOXD13 and GDF11 genes. It is one study, not repeated that we know of, at large doses. There are no human pregnancy data. People who are pregnant or trying to conceive should talk to their doctor before using terpene or essential oil products. Animal research ⁹
Disinfectant poisonings with terpineol in the mixture. Two hospital reports (1978 and 1984) concern people poisoned with Dettol, a disinfectant described as containing chloroxylenol and terpineol. One abstract describes a woman, 28 weeks pregnant, who swallowed 300 ml on purpose. The products are mixtures, and the abstracts do not say which ingredient did the harm, so none of this can be blamed on terpineol alone. Case report ²⁸

Side effects 7

Effect	How often	Severity and recovery	Evidence
Skin irritation (redness, itching) from the pure chemical A classification of the pure chemical, not a measured rate in users.	98.9% of 2,747 company reports notified skin irritation as a hazard class	mild to moderate Not described	Authoritative guidance ³²
Serious eye irritation from the pure chemical Keep terpene oils away from the eyes. A 2% foam of a different molecule (terpinen-4-ol) caused no eye irritation in a patch and egg-membrane test.	81.8% of 2,747 company reports	moderate Not described	Authoritative guidance ³²
Skin allergy (allergic contact dermatitis) Alpha-terpineol is not among the main sensitisers named for tea tree oil, and it was negative in a rat screening test. Whole oils that contain it, including old air-exposed ones, can still cause allergy.	No rate for alpha-terpineol. For tea tree oil, 0.1% to 3.5% of people patch-tested in routine series reacted	moderate Not described	Review ^{40 6}
Slower stomach emptying In rats, 50 mg/kg by gavage delayed emptying of a liquid meal through the vagus nerve.	No human data	unknown Not studied	Animal research ³⁹
Birth defects and lower fetal weight (rats) One study. No human data.	Dose-dependent at 75 to 300 mg/kg in pregnant rats	serious (in rats) Not applicable	Animal research ⁹
Poisoning after swallowing a disinfectant containing terpineol and chloroxylenol Mixtures; terpineol cannot be singled out. Poison centres should be called after any swallowing of disinfectant.	Case reports only	serious Not described in the abstracts	Case report ²⁸
No adverse events reported in a CBD-plus-terpene trial 1 mg of alpha-terpineol with 300 mg CBD and seven other terpenes. A company-funded trial; short; not a long-term safety study.	0 reported in 125 adults over 4 weeks	none reported Not applicable	Controlled trial ³⁶

Liver

No human case of liver injury from alpha-terpineol was found in the sources read, and LiverTox was not read. In a mouse tumour study, no evident biochemical or blood toxicity was reported after alpha-terpineol. EFSA used a no-observed-adverse-effect level of 250 mg/kg body weight a day from subchronic rat data on terpineol in its cajuput oil opinion, but the underlying study was not read. ^{7 4}

How often. No human rate was found.

Monitoring. No agency monitoring advice was read.

This is a safety connection. It is not evidence that Terpineol supports liver health.

Medicines and supplements 4

With	Why it matters	Importance	Evidence	What to do
THC (cannabis) cannabis	In frog egg cells with human CB1 or CB2 receptors, terpineol (isomer not stated) boosted THC's activation of CB1 more than expected. In mice, alpha-terpineol's pain effect was weaker when CB1 or CB2 receptors were missing.	Unknown. No study measured whether terpineol changes THC's effects, impairment or side effects in people.	Laboratory research Not enough evidence ^{24 3}	Do not assume a terpene makes THC safer or milder. Impairment, anxiety and dependence risks from THC still apply.
Antibiotics (colistin) drug	In the lab, alpha-terpineol with colistin damaged the membranes of colistin-resistant bacteria and was synergistic.	A lab finding for resistant bacteria, not a clinical interaction and not a recommendation.	Laboratory research Not enough evidence ³⁸	Do not add terpene products to antibiotic treatment unless a doctor says so.
Oral medicines that need quick absorption drug	In rats, alpha-terpineol slowed stomach emptying through the vagus nerve. If that happened in people, it could change the timing of oral medicines.	Unknown; not tested in people.	Animal research Not enough evidence ³⁹	Ask a pharmacist if you take time-critical oral medicines and use concentrated terpene products.
Prescription medicines, sedatives, alcohol and blood thinners in general drug	No studies of alpha-terpineol with these were found, and no work on which human liver enzymes handle it.	Unknown.	Gap Not enough evidence	Ask a doctor or pharmacist before combining terpene products with medicines.

Who should check first 5

Situation	Advice	Evidence
Sensitive skin, eczema, or a past reaction to fragrances or tea tree oil	Avoid putting concentrated terpene oils on the skin. Old oils that have been exposed to air are more likely to sensitise. Ask a dermatologist about patch testing.	Review ^{40 32}
Pregnancy and breastfeeding	No human data. One rat study found fetal harm at large doses. Ask your doctor before using essential oils, terpene products or cannabis. LactMed was not read.	Animal research ⁹
Children, teenagers and older adults	No studies of alpha-terpineol in these groups were found. The risks of THC for teenagers (thinking, mental health, dependence) and for older adults are covered on the THC page.	Gap
Mental health conditions, psychosis risk, anxiety, and cannabis use disorder	Alpha-terpineol itself has no data on these. If it comes with THC in cannabis, the THC risks apply. See the THC page. Cannabis hyperemesis syndrome and driving impairment are also THC-containing cannabis issues; no source read links them to alpha-terpineol.	Gap
Swallowing disinfectants, cleaning products or concentrated oils	Never swallow them. Call a poison centre or emergency services.	Case report ²⁸

Overdose, product quality and regulators

Summary. No human toxicity study of alpha-terpineol on its own was found. Animal data are mixed: EFSA applies a no-effect level of 250 mg/kg body weight a day for terpineol from older rat studies (quoted, not read), a mouse tumour study saw no evident blood toxicity, and a 2026 rat study found birth defects at 75 to 300 mg/kg.

Animal. Rats: dose-dependent embryo toxicity and skeletal malformations at 75, 150 and 300 mg/kg during organ formation (2026). Mice with tumours: no evident biochemical or haematological toxicity (2018). Rats: delayed stomach emptying at 50 mg/kg (2016). The screening lymph-node test in rats was negative for terpineol (2007).

Human doses studied. 1 mg a day inside a mixture with 300 mg CBD and seven other terpenes, for 4 weeks, in 125 adults with insomnia. A 2% terpinen-4-ol foam (a different molecule) in a human patch test.

Overdose response. Hospital reports describe severe poisoning after swallowing Dettol (chloroxylenol and terpineol); outcomes are not given in the abstract read, and the ingredient responsible is unknown.

Genotoxicity. In a mouse sarcoma cell line, alpha-terpineol at 100 to 500 micrograms/mL caused DNA fragmentation and micronuclei. That is how it kills tumour cells in a dish, and it is also a reason for caution; no test in normal human cells or in people was read.

Terpene amounts on cannabis and scent-product labels are not reliable guides. Validated lab methods can measure alpha-terpineol in cannabis, but we found no study checking whether label figures for alpha-terpineol are correct.

It can be measured, but results depend on method and sample. Alpha-terpineol is one of ten terpenes that two validated cannabis methods (GC-MS and GC-FID) measure. Values in our lab data come from a GC-FID study with GC-MS confirmation of one California dispensary's samples and differ in unit from other sources, so numbers cannot be compared across studies. ^{11 12 5}

'Terpineol' on a label can mean a mix of isomers. Industry safety assessments list 'terpineol' (CAS 8000-41-7) separately from alpha-terpineol (CAS 98-55-5 in PubChem), and alpha-, beta-, gamma-terpineol and terpinen-4-ol are different molecules. A product that says only 'terpineol' may be a blend. ^{33 2}

Oils that contain it vary from batch to batch. Alpha-terpineol was 3.11 to 4.66% of seven tea tree oils, 1.4 to 5.3% of one pine species' needle oil and 6.53 to 9.28% of five batches of cajuput oil. Oils from different species or places can differ. ^{34 1 4}

Body	Action	Date
US Food and Drug Administration (Code of Federal Regulations, Title 21, section 172.515) (United States)	Lists alpha-terpineol (p-menth-1-en-8-ol) and beta-terpineol among synthetic flavouring substances and adjuvants that may be safely used in food, used in the minimum quantity required and following good manufacturing practice. Gamma-terpineol is not on that list. source	2026-10-25
European Food Safety Authority (FEEDAP Panel opinion on cajuput oil, 2024) (European Union)	Lists alpha-terpineol (FLAVIS number 02.014) in the table of components of cajuput oil that are in the EU register of flavouring substances, and treats cajuput oil, which is about 8% alpha-terpineol, as a skin and eye irritant and a dermal and respiratory sensitiser. source	2026-10-25
Company hazard notifications to the European Chemicals Agency inventory (as summarised by PubChem) (European Union / EEA)	For alpha-terpineol, companies most often notify causes skin irritation (H315, 98.9%) and causes serious eye irritation (H319, 81.8%); 1.1% of reports said it does not meet GHS hazard criteria. PubChem notes the classifications vary between notifications. source	2026-10-25

When to get medical help

Someone has swallowed a disinfectant, cleaning product or concentrated essential oil and is vomiting, drowsy, coughing, struggling to breathe or has a burning mouth (get emergency help and call a poison centre).
A rash that spreads quickly, blisters, or swelling of the face or lips after skin contact with a terpene or essential oil product.
Eye pain, redness or blurred vision after terpene oil gets in the eye (rinse with clean water and get urgent care).
Wheezing, chest tightness or trouble breathing after breathing vapour or scent, especially with asthma.
Pregnancy: any exposure to concentrated terpene products by mouth, a question for your doctor or midwife.
Severe anxiety, confusion or loss of touch with reality after cannabis products (see the THC page).

Stop using the product 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

What is terpineol?

Terpineol is a small plant scent molecule (a monoterpene alcohol, C10H18O). Usually the name means alpha-terpineol. Cannabis makes it, and so do tea tree, cajuput and pine oils and lilac flowers.

^{33 34 11}

Which terpineol do studies mean?

Most mean alpha-terpineol. Beta-terpineol and gamma-terpineol are other isomers (one cell paper in this page is about gamma-terpineol). Terpinen-4-ol, sometimes called 4-terpineol, is a different molecule that makes up a large part of tea tree oil. Industry papers also use plain 'terpineol' for a blend. Check which one a source means before comparing results.

^{33 37 34}

Where is terpineol found?

In tea tree oil (3.11 to 4.66% in seven oils), cajuput oil (about 8% in five batches), some pine oils (1.4 to 5.3%), lilac flowers, lemon leaf oil of one type, orange juice volatiles and cannabis. Abstracts also name Eucalyptus species. The lime oils in one study did not name it.

^{34 4 27 1 16 17 10}

Which cannabis strains have the most terpineol?

In our lab data, 12 named strains have a measurement, from 0.1 mg/g (Fortune Cookies) to 0.9 mg/g (Gelato), all means of 5 to 10 samples from one California dispensary in 2015 to 2016. The same strain name varies between samples, and these numbers say nothing about effects.

⁵

Is there human research on terpineol?

Very little. No trial has tested alpha-terpineol on its own. One company-funded trial gave adults with insomnia a capsule with 300 mg CBD and eight terpenes including alpha-terpineol. Studies of terpinen-4-ol for eyelid mites are about a different molecule.

^{36 35}

Does terpineol help with pain?

In mice it reduced pain behaviour in several tests, including nerve-injury pain, and the effect depended in part on cannabinoid receptors. No one has tested it for pain in people, so no one knows.

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Does terpineol help with sleep or anxiety?

There is no evidence for alpha-terpineol itself. A CBD-plus-eight-terpene mixture slightly raised deep plus REM sleep in a company-funded trial, and the rat anxiety study's abstract names no alpha-terpineol effect.

^{36 13}

Does terpineol change how THC feels?

Unknown. In frog egg cells with human receptors, terpineol boosted THC's activation of CB1. Nobody has tested this in people, and THC's impairment, anxiety and dependence risks do not go away.

^{24 3}

Is terpineol safe?

There is not enough human data to say. The pure chemical is notified as a skin and eye irritant. Oils that contain it can cause skin allergy, especially when old. One rat study found fetal harm at large doses. Ask a doctor or pharmacist before using concentrated products.

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Is terpineol safe in pregnancy?

No human data exist. A 2026 rat study found lower fetal weight and skeletal malformations at 75 to 300 mg/kg. People who are pregnant or breastfeeding should ask their doctor before using essential oils, terpene products or cannabis.

⁹

Is terpineol the same as tea tree oil?

No. Tea tree oil is a blend of many compounds, mostly terpinen-4-ol (about 38 to 44%) with 3 to 5% alpha-terpineol. The eyelid-mite studies are about terpinen-4-ol, not alpha-terpineol.

^{34 35}

Can terpineol treat cancer or infections?

No. It killed tumour cells and bacteria in dishes and slowed one glioblastoma model in mice, but nothing has been shown in people. Do not use it in place of treatment.

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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 read the abstracts of about 38 sources, read the EFSA cajuput oil opinion in full through PubMed Central, read the FDA flavouring list through the Electronic Code of Federal Regulations, read PubChem for chemical identity and hazard notifications, and used our own cultivar lab-data file for the cannabis numbers. We say which sources we could not read.
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, and none will be added for terpineol. This page is information, not a recommendation to use it.

Sources 41

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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Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.