Phytosterols for Hair: What the Research Shows

Phytosterols are plant compounds found in nuts, seeds, olive oil and legumes. The hair evidence on them is thin and indirect: a placebo-controlled trial of a saw palmetto oil that contains beta-sitosterol reduced hair fall, but the oil is a mixed product, and a small pilot used a multi-ingredient supplement.

Here's what the two hair studies found, and what they can't tell you about phytosterols on their own.

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Key Takeaways

• Phytosterols are bioactive compounds in plant cell membranes. Nuts, seeds, olive oil and legumes are dietary sources.
• In a 16-week placebo-controlled trial of 80 people, a standardized saw palmetto oil (2 to 3% beta-sitosterol) reduced hair fall and increased hair density.
• A 24-week pilot of 10 people used a multi-ingredient supplement that included beta-sitosterol, with improved hair counts and no control group.
• We found no trial of isolated phytosterols for hair.

What Are Phytosterols?

Phytosterols are bioactive compounds found in plant cell membranes. Beta-sitosterol is one of them.

Do Phytosterols Help Hair?

Possibly, as part of other products, but it isn't established for phytosterols alone. In both hair studies, beta-sitosterol was one component of a larger formula.

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Getting Phytosterols

• From food. Nuts, seeds, olive oil and legumes.
• Supplements and oils vary in content; look for the amount of beta-sitosterol on the label.
• Expect time. The trials ran for 16 and 24 weeks.

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Soy isoflavones are another plant compound people compare; see soy isoflavones and hair.

See also: Pygeum Bark for Hair: What the Research Shows · Saw Palmetto for Hair: What the Research Shows

What The Research Shows

What Phytosterols Are

Phytosterols are found in plant cell membranes and are widely distributed as dietary lipids in plants such as nuts, seeds, olive oil and legumes. A review of the literature on beta-sitosterol reports many biological properties in lab and animal studies, and calls for more research on clinical use (Dwivedi et al., 2025).

Saw Palmetto Oil Trial

In a double-blind, placebo-controlled, four-arm study of 80 men and women aged 18 to 50 with mild-to-moderate androgenetic alopecia, a standardized saw palmetto oil (VISPO, 2-3% beta-sitosterol) was given as a 400 mg capsule or a 20% topical for 16 weeks. Hair fall fell by up to 29% (oral) and 22.19% (topical), and hair density rose by 5.17% and 7.61%. Oral VISPO also lowered serum DHT. The effect on the anagen/telogen ratio was not significant, and no serious adverse effects were observed (Sudeep et al., 2023). The product is a whole oil, so the results can't be credited to phytosterols alone.

A Multi-Ingredient Pilot

Ten adults with androgenetic alopecia took Forti5, a supplement containing green tea extract, omega fatty acids, vitamin D3, melatonin, beta-sitosterol and soy isoflavones, for 24 weeks. Eight of ten were rated improved, with a significant increase in terminal hair count and hair mass index. It was open-label with no control group (Nichols et al., 2017).

Beta-sitosterol (phytosterols) is one of the ingredients in FullyVital's Hair Revival Supplements. For how the evidence for each ingredient in the line stacks up, see our evidence-tier breakdown.

Frequently Asked Questions

Do phytosterols help hair growth?

Not shown on their own. A saw palmetto oil containing beta-sitosterol reduced hair fall in a placebo-controlled trial, but it is a mixed oil.

What foods contain phytosterols?

Nuts, seeds, olive oil and legumes.

Are phytosterols safe?

No serious adverse effects were seen in the saw palmetto oil trial. Talk to your doctor before taking supplements, especially if you're pregnant, breastfeeding, have a condition or take medication.

References

1. Dwivedi J, Wal P, Sachan P, et al. Aspects of β-sitosterol's Pharmacology, Nutrition and Analysis. Curr Pharm Biotechnol. 2025. PubMed
2. Sudeep HV, Rashmi S, Jestin TV, et al. Oral and Topical Administration of a Standardized Saw Palmetto Oil Reduces Hair Fall and Improves the Hair Growth in Androgenetic Alopecia Subjects - A 16-Week Randomized, Placebo-Controlled Study. Clin Cosmet Investig Dermatol. 2023. PubMed
3. Nichols AJ, Hughes OB, Canazza A, et al. An Open-Label Evaluator Blinded Study of the Efficacy and Safety of a New Nutritional Supplement in Androgenetic Alopecia: A Pilot Study. J Clin Aesthet Dermatol. 2017. PubMed