Tulsi (Holy Basil) in Ayurveda
Tulsi (holy basil) is a sacred and medicinal plant in Ayurveda; here is what trials of tulsi extracts have and have not shown, plus safety and quality questions.
Content last updated . This page has not been medically reviewed.
What tulsi is
Tulsi is the Hindi name for holy basil, a small aromatic herb grown across India. Botanists call it Ocimum sanctum or Ocimum tenuiflorum. It is native to the Indian continent.[1] This page covers the Ayurvedic angle and the research. For the tea itself, see our guide to holy basil and tulsi tea.
How it is described in Ayurveda and traditional medicine
A short review of its uses says that in traditional systems of medicine, different parts of the plant have been recommended for bronchitis, asthma, malaria, diarrhea, dysentery, skin diseases, arthritis, painful eye diseases, chronic fever and insect bites.[2] A systematic review describes tulsi as highly revered for its medicinal uses within the Ayurvedic and Siddha medical systems.[1]
These are traditional uses. They tell you what practitioners historically reached for. They do not tell you the plant works for those problems. For how Ayurveda groups herbs by taste and effect, see how Ayurvedic herbs are classified. I did not read a primary classical text for tulsi's listed properties, so none are stated here.
What research has measured
Overview (promising but limited). A 2017 systematic review looked for human studies of tulsi in books, theses, conference proceedings and databases, including Indian medical databases. It found 24 studies reporting effects on metabolic disorders, cardiovascular disease, immunity and neurocognition. All reported favorable outcomes and none reported significant adverse events.[1] The reviewers themselves say more work is needed on dose, dose form and who benefits. When every study in a body of research reports a good result, that can also point to small studies and publication bias, so read this as encouraging, not settled.
| Question | What the source found | Strength |
|---|---|---|
| Stress and sleep | An 8-week trial of 100 adults with stress compared 125 mg of a branded extract twice daily with placebo. The extract group improved more on a perceived stress scale and an insomnia scale, and had lower hair cortisol.[3] The study was funded by the extract's maker.[3] | Promising but limited |
| Anxiety | A 60-day program in 35 people with generalized anxiety disorder reported improved scores, but the report describes no placebo group.[4] | Insufficient evidence |
| Thinking and stress markers | A 30-day placebo-controlled study of a leaf extract found improved reaction times and some cognitive test results. Between-group differences in stress measures such as cortisol and an anxiety scale were not significant.[5] | Promising but limited |
| Blood sugar | A 1996 single-blind crossover trial of holy basil leaves in people with type 2 diabetes reported lower fasting and after-meal glucose than during placebo leaves.[6] | Promising but limited, and old |
Small trials, and different extracts and doses make it hard to compare studies. No trial here shows that tulsi replaces diabetes or anxiety treatment. For goal pages that weigh all the evidence, see Ayurveda for stress, anxiety and depression and Ayurveda for type 2 diabetes and weight.
Frequently asked questions
Is tulsi the same as holy basil?
Yes. Tulsi is the Hindi name for holy basil, Ocimum sanctum (also called Ocimum tenuiflorum).[1]
Does tulsi reduce stress?
One placebo-controlled 8-week trial in 100 adults found lower perceived stress and better sleep scores with a branded extract, but the funder was the product's maker and the evidence is limited.[3]
Can tulsi lower blood sugar?
A small single-blind crossover trial published in 1996 reported lower glucose with holy basil leaves in people with type 2 diabetes.[6] It is not a replacement for diabetes treatment; ask your care team first.
Is tulsi safe in pregnancy?
Safety in pregnancy is not established. A rat study found reversible effects on sperm,[7] and animal work suggests antifertility activity,[2] so ask your clinician before taking medicinal amounts.
Are there side effects?
A systematic review of human studies found no significant adverse events reported,[1] but the studies were small and short, so absence of reports is not proof of safety.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety and cautions
Across the studies in the 2017 review, no significant adverse events were reported,[1] and the 8-week stress trial reported no major adverse effects.[3] That is reassuring for short-term use, but the trials were small and short.
Pregnancy and fertility: in rats, a leaf extract given for 48 days reduced sperm count and movement, and the effect reversed two weeks after stopping.[7] A short review also lists antifertility activity among the proposed actions of the plant.[2] This is animal research and may not apply to people, but it is a reason to ask a clinician before taking medicinal amounts if you are pregnant or trying to conceive. See pregnancy and breastfeeding safety.
If you take medicine for diabetes, a blood sugar-lowering herb could in theory add to its effect. I did not find a source I could read that tests this combination, so the point is to tell your pharmacist or doctor about any tulsi supplement. See how herb-medicine interactions work.
Quality: tulsi supplements are sold as leaf powders, extracts and teas, and strength varies between products. The trials above used specific extracts, so their results do not automatically apply to a different product. For general product-quality problems in Ayurvedic products see Ayurvedic products: heavy metals and product quality.
When to see a doctor first
Long-lasting anxiety, low mood, thirst and frequent urination, or poor sleep deserve a proper medical assessment. Do not stop or change prescribed medicine because of an herb.