Summary
-
What is holy basil?
Holy basil (Ocimum sanctum or Ocimum tenuiflorum) is a shrub in the basil family. Holy basil is also called by its Ayurvedic name, "tulsi." The leaves of holy basil contain compounds call triterpenes, including oleanolic and ursolic acid, that laboratory tests show to have anti-inflammatory, blood-sugar lowering and immune system effects. Holy basil leaves also contain eugenol, which may have analgesic effects. In supplements, holy basil is typically sold as a leaf powder (whole, dry crushed leaves) or as an extract (powder or liquid) (see What It Is). -
What does holy basil do?
Preliminary clinical studies suggest holy basil may reduce symptoms of stress and anxiety and may modestly lower blood sugar levels in people with type 2 diabetes. However, the chemical make-up of holy basil extracts and powders used in some of these studies was not well defined, and more research is needed to confirm these findings (see What It Does). -
What did CL's tests of holy basil find?
Most of the holy basil supplements ConsumerLab tested failed to contain even the minimum amount of total triterpenes expected or claimed on the label. Amounts of triterpenes in holy basil supplements varied widely — from as little as 0.43 mg to 34.8. mg per suggested serving, and only 3 of the 8 products tested contained their expected amounts. In addition, one product was found to be contaminated with lead (see What CL Found). 
Which is the best holy basil supplement?
Among the products that passed all tests and were Approved, ConsumerLab selected one that provided the best quality and value as its Top Pick for Holy Basil.-
Safety and side effects of holy basil:
Holy basil may cause nausea or diarrhea. Due to its potential blood sugar lowering effect, it should be used with caution in people with hypoglycemia and those taking blood sugar lowering medications. Women who are pregnant or breastfeeding should not take holy basil (see Concerns and Cautions).
