Holy basil (tulsi) supplement: what studies show and how to pick one
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- Holy basil leaf extract, 500 mg. Best for: Adults who want a standardized tulsi extract. See options on Amazon
- Organic tulsi extract capsules. Best for: Buyers who prefer certified organic herbs. See options on Amazon
- Holy basil leaf capsules. Best for: People who want whole leaf rather than a concentrated extract. See options on Amazon
What holy basil is
Holy basil, or tulsi, is native to the Indian subcontinent and highly regarded in the Ayurvedic and Siddha medical systems. A 2017 systematic review in Evidence-Based Complementary and Alternative Medicine notes laboratory, animal and human studies describing adaptogenic, antimicrobial, anti-inflammatory and other actions.
Supplement labels use two scientific names, Ocimum tenuiflorum and Ocimum sanctum, for the same plant. It is different from the sweet basil used in cooking.
What the human research shows
2017 systematic review. Researchers found 24 human studies reporting effects on metabolic disorders, cardiovascular disease, immunity and neurocognition. All reported favorable outcomes and none reported significant adverse events. The authors suggested tulsi may help lifestyle-related conditions such as diabetes, metabolic syndrome and psychological stress, but said more studies are needed to clarify dose, form and who benefits most.
2022 stress trial. An 8-week randomized, double-blind, placebo-controlled trial in Frontiers in Nutrition gave 100 adults age 18 to 65 either 125 mg of a standardized Ocimum tenuiflorum extract twice daily or placebo.
| Measure | Result vs placebo |
|---|---|
| Perceived stress score | Greater improvement |
| Insomnia score | Greater improvement |
| Hair cortisol at week 8 | Lower |
| Response to a lab stress test | Smaller rises in cortisol and blood pressure |
The extract was well tolerated with no major adverse effects. The authors said sleep findings need confirmation with gold-standard sleep measures.
Limits of the evidence
The research base is still small. The 2017 review called for more work on mechanisms, dosage and dose form. The 2022 trial tested one branded extract for 8 weeks, so results may not apply to other products or longer use. Holy basil is not a treatment for anxiety disorders or depression; see a health care provider for those.
Safety
- Tolerability. The studies reviewed reported no significant adverse events, and the 2022 trial reported no major adverse effects over 8 weeks.
- Pregnancy and nursing. NOW Foods' label says holy basil is not recommended for pregnant or nursing women.
- Medicines and conditions. NOW Foods advises consulting a physician if you take medication or have a medical condition. This matters most if you take medicine for blood sugar, since the 2017 review discusses tulsi in diabetes.
- Children. NOW Foods labels its product for adults only.
How to choose a holy basil supplement
- Leaf extract. NOW Foods uses tulsi leaf extract, 500 mg per capsule, standardized to at least 2% ursolic acid.
- Standardization marker. Some products list ursolic acid; others list an extract ratio such as 20:1 or 25:1. Compare how each label defines strength.
- Dose. The 2022 trial used 125 mg twice daily of one extract; NOW Foods directs 1 capsule 1 to 2 times daily with food. Different extracts are not interchangeable mg for mg.
- Organic and vegan. Many products are organic and use plant-based capsules.
- Tea option. Tulsi tea is another way to try the herb, though tea strength is not standardized.
What to look for when you buy
Holy basil leaf extract, 500 mg
Best for: Adults who want a standardized tulsi extract
NOW Foods lists 500 mg of Ocimum tenuiflorum leaf extract standardized to at least 2% ursolic acid, taken 1 to 2 times daily with food.
Watch out: Not for pregnancy or nursing. Ask your doctor if you take medicine for blood sugar or other conditions.
See options on AmazonOrganic tulsi extract capsules
Best for: Buyers who prefer certified organic herbs
Organic tulsi extracts are widely sold in vegan capsules, often listing an extract ratio.
Watch out: A ratio like 25:1 does not tell you the active compound content. Compare labels carefully.
See options on AmazonHoly basil leaf capsules
Best for: People who want whole leaf rather than a concentrated extract
Whole leaf capsules are closer to traditional use and simple to dose.
Watch out: Not the same as the standardized extract used in the 2022 stress trial.
See options on AmazonQuestions people ask
- What is holy basil supplement good for?
- It is mainly used for stress. A 2022 trial found lower perceived stress and better sleep scores after 8 weeks, and a 2017 review found favorable results across 24 small human studies.
- When should I take holy basil?
- Follow the label. NOW Foods suggests 1 capsule 1 to 2 times daily with food; the 2022 trial used a twice-daily dose.
- Is holy basil the same as regular basil?
- No. Holy basil (tulsi) is Ocimum tenuiflorum, a different plant from the sweet basil used in cooking.
- Is holy basil safe?
- Studies reported no significant adverse events, but long-term data are limited. It is not recommended during pregnancy or nursing.
- Does holy basil lower cortisol?
- In the 2022 trial, hair cortisol was lower at week 8 and cortisol rose less during a lab stress test compared with placebo.
- Does holy basil help with sleep?
- In the 2022 trial, insomnia scores improved more than with placebo, but the authors said gold-standard sleep measures are needed to confirm it.
- How long does holy basil take to work?
- The 2022 trial measured results after 8 weeks of daily use. There is little research on shorter or longer courses.
Sources
- The Clinical Efficacy and Safety of Tulsi in Humans: A Systematic Review of the Literature (pmc.ncbi.nlm.nih.gov), Evidence-Based Complementary and Alternative Medicine (PMC5376420)
- A randomized, double-blind, placebo-controlled trial investigating the effects of an Ocimum tenuiflorum (Holy Basil) extract (Holixer) on stress, mood, and sleep in adults experiencing stress (pmc.ncbi.nlm.nih.gov), Frontiers in Nutrition (PMC9524226)
- Holy Basil Extract 500 mg Veg Capsules (www.nowfoods.com/products/supplements/holy-basil-extract-500-mg-veg-capsules), NOW Foods