Holy Basil and Stress: What the Human Trials Actually Show

The Oasis Health Journal · Submitted July 23, 2026 · 8:17 PM ET

Holy basil is a plant in the mint family. It is not the basil you put on pizza. In India it is called tulsi, it grows in a lot of courtyards, and it has been used in Ayurveda for a very long time. The reverence is old. The human research is younger and smaller. Here is what the trials actually measured.

What it is

Holy basil goes by two Latin names, Ocimum sanctum and Ocimum tenuiflorum, which are the same plant that could not settle on one name. It gets filed under 'adaptogen,' a loose word for herbs people take to handle everyday stress. It is a different plant from the sweet basil in a caprese salad, so a windowsill pot of it will not improve your pasta.

The stress trial

The most cited study is a randomized, double-blind, placebo-controlled trial from 2012. About 150 adults took either a holy basil extract (1,200 mg of actives a day) or a placebo for six weeks. The people on holy basil rated their overall stress symptoms, things like feeling worn out, forgetful, and sleeping poorly, as improving more than the placebo group did. The authors put the difference at roughly 39 percent and reported no adverse events. The catch is that the symptoms were self-scored on a questionnaire, which is a softer measurement than a lab value.

The anxiety trial

An earlier study followed 35 adults who had generalized anxiety. They took 500 mg of holy basil leaf twice a day for 60 days. Over those two months their anxiety, stress, and low-mood scores fell, and their attention scores went up. It is a tidy result with one large caveat: there was no placebo group. Everyone got the herb, so the improvement cannot be cleanly separated from time, attention, and the ordinary effect of being enrolled in a study.

The attention trial

A 2015 study gave healthy volunteers either 300 mg a day of a holy basil leaf extract or a placebo for 30 days, then ran them through timed thinking tests. Compared with placebo, the holy basil group was a little faster and made fewer errors on two standard tasks (the Sternberg memory test and the Stroop test), and one brain-wave timing marker shifted in their favor. Small study, short window, but it had a placebo arm, which makes it more useful than its size suggests.

The review that gathered it all

In 2017 two researchers pulled together every human study on tulsi they could find, 24 in total, spanning metabolic, heart, immune, and brain-and-mood outcomes. Their summary was that the studies leaned positive and that none reported a serious safety problem. Their other conclusion was the honest one: the doses and the forms are all over the place, and the field still needs bigger, longer trials before anyone gets confident. That is a review telling you the research is promising and unfinished in the same breath.

What this adds up to

Holy basil is one of those herbs where the tradition runs deep and the clinical file is thin but not empty. The trials are mostly small, mostly short, and several come from the same part of the world, so this is early evidence, not a closed case. Doses in the studies ran from about 300 to 1,200 mg of extract a day. It usually turns up as holy basil capsules or as a tulsi tincture, and people tend to reach for it around everyday stress rather than for anything dramatic. Those who take it in the evening sometimes pair it with something like magnesium glycinate. None of that is a promise. It is just where the plant currently stands.

This article is for education, not medical advice. Talk with your clinician before starting a new supplement, especially if you are pregnant, nursing, or taking medication.

Sources

1. Saxena RC, Singh R, Kumar P, Negi MP, Saxena VS, Geetharani P, Allan JJ, Venkateshwarlu K. Efficacy of an Extract of Ocimum tenuiflorum (OciBest) in the Management of General Stress: A Double-Blind, Placebo-Controlled Study. Evid Based Complement Alternat Med, 2012;2012:894509. PubMed
2. Bhattacharyya D, Sur TK, Jana U, Debnath PK. Controlled programmed trial of Ocimum sanctum leaf on generalized anxiety disorders. Nepal Med Coll J, 2008;10(3):176-179. PubMed
3. Sampath S, Mahapatra SC, Padhi MM, Sharma R, Talwar A. Holy basil (Ocimum sanctum Linn.) leaf extract enhances specific cognitive parameters in healthy adult volunteers: A placebo controlled study. Indian J Physiol Pharmacol, 2015;59(1):69-77. PubMed
4. Jamshidi N, Cohen MM. The Clinical Efficacy and Safety of Tulsi in Humans: A Systematic Review of the Literature. Evid Based Complement Alternat Med, 2017;2017:9217567. PubMed