Holy Basil
Ocimum tenuiflorum
Also known as: Tulsi, Sacred Basil, The Incomparable One
Overview
Considered the most sacred plant in Ayurveda. Tulsi is a traditional adaptogen: an 8-week randomized trial found it lowered perceived stress and cortisol, and smaller trials point to effects on blood sugar and mental clarity. Its traditional use for respiratory support has not been tested in human trials.
Proposed mechanism
Holy Basil (tulsi) contains ursolic acid, rosmarinic acid, and eugenol. In laboratory and animal studies these constituents show antioxidant and anti-inflammatory activity, including reduced COX-2 signaling, and isolated eugenol interacts with GABA-A receptors — the receptor family targeted by common calming medications. This preclinical work is what is usually cited to explain tulsi's traditional use for stress, but it has not been confirmed in people, and even in rodents the calming effects observed have not been traced back to that receptor. Human trials, including a placebo-controlled trial in 150 adults, report reduced stress symptoms, though results on formal anxiety scales are less consistent. Effects on cortisol are not established: the one trial that measured salivary cortisol found improvement within the tulsi group but no significant difference versus placebo, and a systematic review of plants and the body's stress-hormone (HPA) axis judged the human evidence for holy basil unclear. Which compounds are responsible has never been tested in people — eugenol on its own has never been trialed for anxiety.
Mechanisms describe how researchers think a compound may act, often from laboratory work — a proposed mechanism is not proof of a clinical effect in people.
Traditional & studied uses
Related pathways
Pathway tags are a research aid for browsing the glossary — they are not a claim that this ingredient treats any condition.