Tulsi, or holy basil (Ocimum sanctum, also called Ocimum tenuiflorum), is a plant native to the Indian subcontinent and highly valued in Ayurvedic and Siddha medicine. It is taken as an adaptogen for stress and for blood sugar, heart health and immunity.
Also known as: holy basil, Ocimum sanctum, Ocimum tenuiflorum, tulasi.
An 8-week stress trial used 125 mg of a holy basil extract twice a day (Lopresti 2022). A 2017 review says the right dose and form still need to be worked out (Jamshidi 2017). These are study protocols, not a recommendation.
It is sold in the US as a dietary supplement. Under the 1994 dietary supplement law (DSHEA), FDA does not approve dietary supplements before they are marketed, and the maker, not FDA, is responsible for safety and labeling.
What studies show: a 2017 systematic review found 24 human studies on metabolic disorders, heart disease, immunity and thinking; all reported favorable results, and the authors say more studies are needed on dosing, form and who might benefit (Jamshidi 2017). In a placebo-controlled trial of 100 stressed adults, 8 weeks of a holy basil extract (125 mg twice a day) improved stress and insomnia scores and lowered cortisol in hair (Lopresti 2022). That trial was funded by the extract's maker, Natural Remedies, and the lead author ran a research company funded by supplement companies.
Safety: none of the studies in the 2017 review reported significant side effects (Jamshidi 2017), and the 8-week trial reported no major side effects (Lopresti 2022). The sources here do not describe drug interactions.
We could not find a single published half-life or time to peak for tulsi that applies to a supplement dose, so we do not list one. Plant and bee products are mixtures of many compounds, so no single figure would describe them.
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