Saw Palmetto for Hair: What the Research Shows

Saw palmetto is one of the most studied plant extracts for hair thinning, and it is described as having antiandrogenic properties. The research is small and mixed: a few randomized trials and cohort studies, one head-to-head comparison with a prescription drug where the supplement did less well, and a recent placebo-controlled trial of one proprietary extract.

Here's what each found.

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Key Takeaways

• A systematic review of five randomized trials and two cohort studies reported positive effects of saw palmetto products in androgenetic alopecia, telogen effluvium and self-perceived thinning, and well tolerated use. The authors said robust high-quality data are lacking.
• In a two-year open-label study of 100 men, 38% taking saw palmetto showed more hair growth, against 68% on finasteride.
• A 90-day placebo-controlled trial of a proprietary extract in 60 adults reported more hair than placebo.
• Larger trials of saw palmetto alone are still needed.

What Is Saw Palmetto?

Saw palmetto (Serenoa repens) is a palm whose berry extract is sold as a supplement, often for hair and prostate health. In hair research, doses of 100 to 320 mg have been studied in oral and topical forms.

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Does Saw Palmetto Help Hair?

Possibly, for some people with pattern hair thinning. The evidence is limited and many studies were small, so it is not a substitute for a doctor's diagnosis or for approved treatments.

Using Saw Palmetto Sensibly

• See a doctor first if you are losing hair. Pattern thinning and other causes need different approaches.
• Be patient and track it. Trials ran for months to two years.
• Tell your doctor you take it, especially if you use other hair-loss medicines or hormonal products.

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What The Research Shows

Systematic Review

A systematic review searched for studies of saw palmetto in alopecia and found five randomized trials and two prospective cohort studies of topical and oral products containing 100 to 320 mg. Reported results included 60% improvement in overall hair quality, a 27% improvement in total hair count, increased hair density in 83.3% of patients, and stabilized progression in 52%. Saw palmetto was well tolerated, with no serious adverse events. The authors cautioned that robust high-quality data are lacking, and that many products combined saw palmetto with other ingredients (Evron et al., 2020).

Compared With Finasteride

In an open-label study, 100 men with mild to moderate androgenetic alopecia took either 320 mg of Serenoa repens daily or 1 mg of finasteride daily for 24 months. Based on global photos, 38% of the saw palmetto group had increased hair growth, against 68% of the finasteride group. The authors observed that finasteride acted at both the front and vertex, while saw palmetto acted mainly at the vertex (Rossi et al., 2012). Finasteride is a prescription medicine; talk to a doctor about it.

Placebo-Controlled Trial

In a randomized, double-blind, placebo-controlled trial, 60 adults with self-perceived thinning hair (half women) took a proprietary saw palmetto fatty acid extract (n = 40) or placebo (n = 20). At 90 days, terminal and total hair counts were significantly higher than placebo in front and back areas, and no adverse events were reported. These are preliminary results of a 6-month study, and the extract was a specific proprietary product (Ablon, 2025).

For how it fits among other supplements studied in men, see hair growth supplements for men.

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

Frequently Asked Questions

Does saw palmetto block DHT?

It is described as having antiandrogenic properties, but the hair trials measured hair outcomes, not hormones.

How long does saw palmetto take to work?

Studies ran from 90 days to 24 months, so expect it to take months, if it helps at all.

Is saw palmetto safe?

The systematic review found it well tolerated, but long-term adverse events were not established. Check with your doctor.

References

1. Evron E, Juhasz M, Babadjouni A, et al. Natural Hair Supplement: Friend or Foe? Saw Palmetto, a Systematic Review in Alopecia. Skin Appendage Disord. 2020. PubMed
2. Rossi A, Mari E, Scarno M, et al. Comparitive effectiveness of finasteride vs Serenoa repens in male androgenetic alopecia: a two-year study. Int J Immunopathol Pharmacol. 2012. PubMed
3. Ablon G. The Safety and Efficacy of a Proprietary Bioactive Fatty Acids Extract From Saw Palmetto (Serenoa repens) for Promoting Hair Growth and Reducing Hair Loss in Adults With Self-Perceived Thinning Hair: 90-Day Results. J Cosmet Dermatol. 2025. PubMed