Holy Basil (Tulsi) for Stress: Two Placebo-Controlled Trials, Both Tied to Extract Makers
Holy basil, or tulsi, is sold as a calming adaptogen. Two placebo-controlled trials of standardized extracts found lower stress scores after 6 to 8 weeks, and both have links to the company that makes the extract. Here is what they measured, how long the safety data run, and who should be careful.
By Kymata Health Editorial Published Last checked
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Nutricost Holy Basil Capsules, 120 Count
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Label: 2 capsules: 500 mg holy basil (Ocimum sanctum) leaf extract, standardized to 2.5% ursolic acid.
Best for trying one bottle: $12.95 one-time (checked Oct 15, 2026).
Key takeaways
From 6 sources- In an 8-week trial of 100 stressed adults, 125 mg of a holy basil extract twice a day improved perceived stress (p = 0.003) and insomnia scores (p = 0.025) more than placebo1.
- A 6-week trial of 150 adults found stress-symptom scores improved 39% more on 1,200 mg a day of a different extract than on placebo2.
- The first trial was funded by Natural Remedies, maker of the extract, and three authors of the second worked at the same company12.
- Across 24 human studies, none reported significant adverse events, but the longest lasted 13 weeks, so long-term safety is not established3. Animal studies also link large doses to reduced fertility, so it is best avoided in pregnancy or when trying to conceive56.
- Tulsi taken alongside a diabetes drug lowered HbA1c more than the drug alone in one trial, so people on glucose-lowering medicines should check with their prescriber3.
What this article covers
1 evidence profileThe evidence, graded
Pulled from the trial tables in our evidence profiles. Grades follow our evidence-grading policy.
Graded findings
2 rows- BGrade BPerceived stress, sleep and cortisol in stressed adultsImproved Perceived Stress Scale (P = 0.003) and Athens Insomnia Scale (P = 0.025) improved more than with placebo; hair cortisol was lower at week 8, and cortisol, amylase and blood-pressure responses to a lab stress test were blunted. Well tolerated.Tulsi (Holy Basil) · RCT · n=100 · 2022 · PMID 36185698
- BGrade BGeneral stress symptomsImproved Total stress-symptom scores fell significantly more than with placebo (39% greater improvement), including forgetfulness, exhaustion and recent sleep problems. No adverse events reported.Tulsi (Holy Basil) · RCT · n=150 · 2012 · PMID 21977056
Where these trials agree: Tulsi (Holy Basil) and stress, counted row by row in the Consensus finder.
The 2022 trial: stress, sleep and cortisol
Holy basil (Ocimum tenuiflorum, also called Ocimum sanctum or tulsi) is an Ayurvedic herb. In a 2022 Australian trial, 100 adults aged 18 to 65 who felt stressed took 125 mg of a standardized extract (Holixer) or placebo twice a day for 8 weeks1.
Perceived Stress Scale scores (p = 0.003) and Athens Insomnia Scale scores (p = 0.025) improved more on the extract than on placebo, and hair cortisol was lower at week 8 (p = 0.025)1. After a lab stress test, the extract group had lower salivary cortisol and amylase (both p = 0.001) and smaller rises in blood pressure1. The extract was well tolerated, with no major adverse effects reported1.
The sleep findings were self-rated; the authors said gold-standard objective sleep measures are needed to confirm them1.
Funding: the trial was funded by Natural Remedies, the extract's maker, which the authors say had no role in design, analysis or writing; the lead author ran a contract research organization that has received funding from nutraceutical companies1.
The 2012 trial: general stress symptoms
An Indian trial randomized 150 adults with general stress symptoms to placebo (79 people) or 1,200 mg a day of a different extract, OciBest (71 people), for 6 weeks2.
Total stress-symptom scores fell significantly more on the extract, with the overall improvement 1.6 times (39%) greater than on placebo; individual symptoms that improved included forgetfulness, frequent exhaustion and recent sleep problems2. No adverse events were reported2.
Funding: the paper carries no funding statement, and three of its authors worked at the research and development centre of Natural Remedies, which makes OciBest2.
What the wider evidence adds
A 2017 systematic review found 24 human studies of tulsi with 1,111 participants, nearly all run in India3. Only 8 used a placebo and only 3 scored 4 or 5 on the 5-point Jadad quality scale, so the authors warned tulsi's effects may have been overestimated3. One author consults for Organic India, which sells tulsi products; the review says the company had no input3.
In a 30-day trial in healthy young adults, 300 mg a day of tulsi leaf extract improved reaction times and error rates on memory and attention tests more than placebo, but changes in salivary cortisol and anxiety scores were seen only within the tulsi group, not against placebo34.
The tulsi page grades each finding. For other herbs sold for stress, see our explainers on ashwagandha, rhodiola and L-theanine.
Who should be careful
Check with a doctor or pharmacist before adding holy basil if any of these apply:
- Diabetes medicines: in a trial included in the 2017 review, 300 mg a day of tulsi taken with glibenclamide lowered blood glucose and HbA1c more than the drug alone, so combined use can change blood-sugar control3.
- Long-term daily use: the longest study in the 2017 review lasted 13 weeks, so the lack of reported side effects does not rule out long-term ones3.
- Switching products: the extracts tested differ (125 mg twice a day of one, 1,200 mg a day of another), and many tulsi studies did not report the plant type, dose form or quality control123.
- Pregnancy, trying to conceive or breastfeeding: in animal studies, large doses reduced embryo implantation and full-term pregnancies, and the Merck Manual advises anyone trying to conceive to avoid holy basil; its safety in breastfeeding has not been studied5. Norway's public health institute concluded in 2023 that intake should be limited for pregnant women and for both men and women trying to conceive, based on animal data on reduced fertility6.
- Thyroid or blood-thinning medicines: holy basil might lower thyroxine and blunt thyroid hormone medicines, and it appears to slow blood clotting, which could add to antiplatelet or anticoagulant drugs and matters before surgery5.
- Ongoing anxiety, low mood or insomnia: these deserve a medical assessment, and the trials above enrolled adults with everyday stress symptoms12.
Quick answers
Common questions
4 answersDoes holy basil lower cortisol?
In one 8-week trial, hair cortisol was lower on the extract than placebo at week 8, and cortisol rose less after a lab stress test1.
How long does tulsi take to work for stress?
Is holy basil tea the same as the extracts tested?
Can holy basil help sleep?
In one trial, self-rated insomnia scores improved more than with placebo (p = 0.025), but the authors said objective sleep measures are needed to confirm it1.
Keep reading
Full evidence profiles
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- ArticleAshwagandha for Testosterone: What the Trials Show (About 57 ng/dL, With Big Caveats)Does ashwagandha raise testosterone, and by how much?
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Where to buy Tulsi (Holy Basil)
Products from brands we partner with that contain Tulsi (Holy Basil). Check the amount per serving against the doses studied, and the label for other ingredients.
Tulsi (Holy Basil) products from partner brands
1 product Paid links · we earn a commission- Quick pickHerbsProNutricost Holy Basil Capsules, 120 Count
2 capsules: 500 mg holy basil (Ocimum sanctum) leaf extract, standardized to 2.5% ursolic acid
$12.95one-timeChecked Oct 15, 2026
References
6 sources. Numbers in the text link here.
Sources cited in this article
6 sources- 1A randomized, double-blind, placebo-controlled trial investigating the effects of an Ocimum tenuiflorum (Holy Basil) extract (Holixer) on stress, mood, and sleep in adults experiencing stressFront Nutr, 2022 · PMID 36185698
- 2Efficacy of an Extract of Ocimum tenuiflorum (OciBest) in the Management of General Stress: A Double-Blind, Placebo-Controlled StudyEvid Based Complement Alternat Med, 2012 · PMID 21977056
- 3The Clinical Efficacy and Safety of Tulsi in Humans: A Systematic Review of the LiteratureEvid Based Complement Alternat Med, 2017 · PMID 28400848
- 4Holy basil (Ocimum sanctum Linn.) leaf extract enhances specific cognitive parameters in healthy adult volunteers: A placebo controlled studyIndian J Physiol Pharmacol, 2015 · PMID 26571987
- 5Holy Basil (Merck Manual Professional Version, dietary supplements)Merck Manual, 2025
- 6Risk assessment of holy basil (Ocimum tenuiflorum L. and Ocimum sanctum L.) and some of the component substances used in herbal teas and food supplementsNorwegian Institute of Public Health (FHI), 2023
Tulsi (Holy Basil) and other dietary supplements are not intended to diagnose, treat, cure or prevent any disease, and these statements have not been evaluated by the FDA. Talk to your clinician or pharmacist before starting a supplement, especially if you take prescription medicines. Product links on this page are paid partner links.