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Tulsi / holy basil

Tulsi (holy basil, Ocimum tenuiflorum) is a revered herb in Ayurveda, where it is called an elixir of life and is held to support longevity and general wellbeing. Small randomised trials in stressed adults report lower perceived stress and better self-rated sleep with tulsi extracts, and older small trials in adults with type 2 diabetes report lower blood glucose, but most studies are small, short and of limited quality. No claim here reaches moderate certainty because the human trials are few, small, mostly conducted with a single proprietary extract or in local journals, and at high or unclear risk of bias. Short-term use was well tolerated in trials; safety beyond about 8 to 13 weeks, in pregnancy and alongside blood-thinning medicines is not established.

  • Mind
  • Sleep

Evidence retrieved up to

What the research shows

In small randomised placebo-controlled trials of adults experiencing stress, tulsi extracts taken for 6 to 8 weeks were associated with greater reductions in self-rated stress symptoms, and in one trial with better self-rated sleep, than placebo.

Low certaintyFurther research is likely to change this.
No known concerns at usual amountsBenefit

Who this is about

adults experiencing everyday stress

Practical note

Graded low: two placebo-controlled trials (100 and 150 participants) of two different proprietary extracts point the same way, but each is small, the outcomes are mostly self-rated scales, the 2022 trial was funded by the extract supplier, and a 2017 systematic review judged most tulsi trials low in quality. The trials used 125 mg of a standardised extract twice a day (2022) and 1200 mg of actives a day (2012); the sleep finding was not confirmed with gold-standard objective measures.

Safety note

Both trials reported no major adverse effects over 6 to 8 weeks.

Sources

Small, mostly low-quality trials in adults with type 2 diabetes reported lower fasting and after-meal blood glucose while taking tulsi leaf than with placebo or usual care alone, so tulsi may help people living well with type 2 diabetes, but the evidence is too weak to rely on.

Very low certaintyThis is uncertain; treat it as a lead, not a finding.
Take care: see the safety noteBenefit

Who this is about

adults with type 2 diabetes

Practical note

Graded very low: the trials are few, small, short (2 to 13 weeks), mostly published in local journals, often unblinded or single-blind, and used varied preparations. The first randomised trial used 2.5 g of leaves a day for 4 weeks; another used 300 mg of extract alongside glibenclamide for 12 weeks.

Safety note

Tulsi may add to the glucose-lowering effect of diabetes medicines; any change to diabetes care belongs with the treating clinician.

Sources

In one randomised trial among young adult volunteers, a tulsi mouthwash lowered dental plaque and gum bleeding scores over 30 days about as much as chlorhexidine, and more than a saline rinse.

Low certaintyFurther research is likely to change this.
No known concerns at usual amountsBenefit

Who this is about

young adult volunteers (medical students)

Practical note

Graded low: a single triple-blind trial of 108 students (36 per arm) over 30 days; downgraded for imprecision and because a single trial cannot show consistency.

Safety note

The trial authors reported no side effects with the tulsi rinse.

Sources

Human trials lasting up to about 13 weeks reported tulsi to be well tolerated, with occasional nausea as the only side effect noted, but safety in longer use, in pregnancy and alongside blood-thinning medicines has not been established.

Low certaintyFurther research is likely to change this.
Take care: see the safety noteUnclear

Who this is about

adults taking tulsi preparations by mouth

Practical note

Graded low: adverse events were poorly reported (eight of 24 studies in the 2017 review did not describe them) and the longest study lasted 13 weeks. The reviewed trials used 300 mg to 3000 mg of leaf aqueous extract a day.

Safety note

In animal studies large doses reduced implantation and full-term pregnancy, so a professional monograph advises against use when trying to conceive or pregnant; breastfeeding safety is unstudied. Tulsi appears to slow blood clotting and may raise bleeding risk with antiplatelet or anticoagulant medicines and around surgery, and may lower thyroxine levels.

Sources

What the tradition holds

Ayurveda holds that tulsi (holy basil) promotes longevity and general wellbeing.

No known concerns at usual amountsBenefit

Who this is about

people following Ayurvedic practice

The tradition's frame

Ayurveda

In Ayurveda tulsi is a sacred, highly revered herb called the elixir of life, used for more than 3000 years and taken regularly as part of a holistic way of living.

Practical note

This records what the tradition holds. The trials summarised in the scientific claims are small and short and do not test longevity.

Vegan note

Tulsi is a plant; check capsule shells and tea blends with honey for animal-derived ingredients.

Safety note

Tulsi tea and culinary use are part of daily life in India; concentrated extracts carry the cautions listed in the safety claim.

Sources