Also known as: Ocimum sanctum, Ocimum tenuiflorum, Tulsi, Sacred basil, Ursolic acid
BotanicalEmerging evidence
An aromatic basil relative central to Ayurvedic practice and Hindu tradition, used as a calming adaptogen. Widely drunk as tea in India, and one of the gentler options in this category.
Typical dose
300.0–1000.0 mg per day
Split across the day, with or without food
What it is
Holy basil is Ocimum sanctum, a fragrant plant related to culinary basil but distinct from it in both taste and composition. Known as tulsi, it holds religious significance in Hindu tradition and is grown in courtyards across India.
Compounds of interest include eugenol, ursolic acid, rosmarinic acid and ocimumosides. Extracts are usually standardised to ursolic acid or total phenolic content, though standardisation practice is less consistent than for better-commercialised botanicals.
Three varieties are used, differing somewhat in composition. Because tulsi is consumed daily as tea by large numbers of people, its acceptability at ordinary intakes is better established than its efficacy at supplemental ones.
How it works
Holy basil is classed as an adaptogen, with the most cited mechanism being modulation of the stress hormone response, similar in principle to ashwagandha though generally described as gentler.
It has antioxidant and anti-inflammatory activity attributed largely to its phenolic compounds, and effects on blood sugar handling have been reported in both animal and human work.
Eugenol, also found in cloves, contributes the characteristic aroma and has documented biological activity of its own, including effects on how readily blood clots at higher intakes.
What the evidence shows
Stress measures are the most studied area. A number of small randomised trials have reported reductions in self-reported stress scores over several weeks, and reviews have generally described the evidence as promising but limited by trial size and quality.
Blood sugar research has produced reasonably consistent findings, with several trials reporting modest improvements in fasting glucose measures.
A recurring limitation is that much of the trial literature comes from a small number of research groups in one country, which is a pattern seen across Ayurvedic botanicals and a fair reason for measured expectations. Overall the evidence is thinner than for ashwagandha, and the effects reported are smaller.
Dosing
Common supplemental range is 300-1,000 mg daily of extract, usually split into two servings. Trials have generally used doses within this band over 6-8 weeks.
As tea, several cups daily is the traditional pattern and a perfectly reasonable way to use it if you like the taste.
Effects reported in trials accrue over weeks rather than acutely. Holy basil is generally described as calming without being sedating, which makes it more flexible on timing than most adaptogens — morning or evening both work.
Generally well tolerated, with a long record of daily consumption as tea. Reported effects are mild and infrequent, mainly digestive upset and occasional nausea on an empty stomach.
Holy basil may lower blood sugar and has a mild effect on how readily blood clots, so check with your doctor before use if you take regular medication.
Animal research has raised questions about effects on fertility at high doses, which is a reason for caution if you are trying to conceive. Long-term human data at concentrated extract doses is limited.
Who should avoid it
Speak to your doctor before use if you take regular medication, particularly anything affecting blood clotting, or if your blood sugar is being managed. Take care if you are trying to conceive, given animal findings on fertility at high doses. Avoid in pregnancy and breastfeeding. Stop before scheduled surgery.
This entry is provided for information only. Food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle. Consult a qualified healthcare professional before use if you are pregnant, breastfeeding, taking medication or under medical supervision.
