Encyclopedia · botanical
Beta-sitosterol
A plant sterol credited with weak anti-DHT activity, but no hair trial has tested it on its own.
Supplement
Cost $
What it is
Beta-sitosterol is a common plant sterol found in saw palmetto, pumpkin seed and many foods. It is a food, supplement and cosmetic ingredient, not a hair drug.
What the studies show
- The only human hair trial that involves it tested a saw palmetto oil standardised to 2 to 3% beta-sitosterol (80 people, 16 weeks). Hair fall and density improved, but the active product was the whole oil, not isolated sitosterol. Sudeep 2023
- Beyond that, we found only delivery-system and computer-modelling studies, and no human trial of isolated beta-sitosterol for hair loss.
Bottom line
Evidence is limited to mechanism and formulation work. Do not buy beta-sitosterol for hair. If you want a plant-sterol approach, see saw palmetto and pumpkin seed oil, which at least have small trials.
Studies 1
Sudeep HV et al. Standardized saw palmetto oil in androgenetic alopecia: 16-week randomized controlled trial. Clin Cosmet Investig Dermatol. 2023
Tested: oral or topical standardised saw palmetto oil vs placebo (manufacturer-funded)
Result: Hair fall fell by up to 29% (oral) and 22% (topical); density rose 5.2% (oral) and 7.6% (topical); serum DHT fell with oral use; anagen/telogen ratio unchanged.
Read the study ↗Related
- Saw palmettoA berry extract with weak DHT-blocking activity that shows small benefits in short, mostly industry-linked trials and clearly less than finasteride in the one head-to-head.
- Pumpkin seed oilA food oil with two small randomised trials for pattern hair loss that look promising but are short, single-centre and unreplicated.
- Antiandrogen comparison for hair lossA side-by-side of the drugs, topicals and supplements that work on the androgen pathway, with who they were studied in and how strong the evidence is.