Is saw palmetto good for androgenetic alopecia or only for mild hair loss?

Hair loss is a common concern, but its origin and treatment vary greatly from person to person. In this context, saw palmetto (Serenoa repens), a plant native to the southeastern United States, has been widely cited as a potential natural solution. But is it truly useful for treating androgenic alopecia (also known as male or female pattern baldness)? Or is its effectiveness limited to milder forms of hair loss?

What is androgenic alopecia and why is it important to differentiate it?

Androgenic alopecia is a progressive form of hair loss caused primarily by genetic and hormonal factors. In this type of alopecia, the culprit is usually a hormone called dihydrotestosterone (DHT), a derivative of testosterone. This hormone binds to hair follicle receptors and, over time, miniaturizes the hair follicle. That is, it causes hair to become increasingly thinner until it stops growing altogether.

Therefore, any effective treatment for androgenetic alopecia should ideally target this hormonal pathway. This is where saw palmetto has gained popularity, as it has been suggested that it can inhibit the enzyme 5-alpha reductase, which converts testosterone into DHT. But is there solid evidence to support this?

How strong is the evidence behind saw palmetto?

One of the most cited studies on the topic was published in 2002 in The Journal of Alternative and Complementary Medicine. This small double-blind, placebo-controlled pilot trial, led by Prager and his team, tested an oral supplement combining saw palmetto extract with beta-sitosterol in men with mild to moderate androgenetic alopecia.

Blinded study staff rated 6 of the 10 men on the active supplement as improved. Although this looks positive, the pilot was very small and short, the supplement combined two ingredients, and the outcome was a staff rating rather than a measured hair count.

The only head-to-head study compared saw palmetto 320 mg a day with finasteride 1 mg a day over 24 months in 100 men with mild to moderate androgenetic alopecia. It was open-label. Improvement was seen in 38% of the saw palmetto group and 68% of the finasteride group (Rossi et al., 2012).

For topical products, an uncontrolled 24-week pilot in 50 men using topical saw palmetto products reported higher hair counts compared with baseline (Wessagowit et al., 2016). With no control group, the effect cannot be separated from placebo or natural variation. The US National Center for Complementary and Integrative Health (NCCIH) says the evidence for saw palmetto in male-pattern hair loss is too limited to allow conclusions.

Does it work best for mild hair loss?

The available studies enrolled only men with mild to moderate hair loss, and none compared results by stage. So they cannot show whether saw palmetto works better in early hair loss than in later stages.

In the early stages of androgenetic alopecia, hair changes are more subtle. Hair follicles have not yet fully miniaturized, meaning the hair has not yet permanently fallen out. At this point, the hair may become finer and weaker, and the hairline or receding hairline may begin to recede, but the damage is not yet irreversible.

In theory, this is where a weaker treatment would have the best chance of helping, because the follicles can still respond. This has not been tested for saw palmetto. Inhibiting the enzyme 5-alpha reductase (which converts testosterone to DHT) may help prevent further miniaturization of hair follicles.

Therefore, at this early stage, when the damage is not as profound, earlier intervention could have a positive impact on hair growth or reducing hair loss. However, once alopecia progresses and hair follicles become severely miniaturized, treatments like saw palmetto may be less effective, as the damaged follicles will not be able to respond as easily.

Is saw palmetto safe?

Saw palmetto is not side-effect-free. A 2009 systematic review of adverse events found that reported side effects were usually mild, most often stomach pain, diarrhoea, nausea, tiredness, headache and decreased libido (Agbabiaka et al., 2009). It noted rare serious case reports whose cause was uncertain, and called for better safety reporting. A 2026 case series describes sexual and psychiatric symptoms in some users that persisted after stopping (Firenzuoli et al., 2026). NCCIH says saw palmetto may be unsafe during pregnancy or breastfeeding. One case report linked it to severe bleeding during surgery, so tell your surgeon if you take it (Cheema et al., 2001).

Saw palmetto is proposed to act on the same enzyme as finasteride. If you had side effects on finasteride, talk to your doctor before trying saw palmetto.

The FDA has not approved saw palmetto as a treatment for androgenetic alopecia, and there are not enough large, rigorous, controlled trials to show that it works for this purpose.

Conclusion: Natural ally or insufficient supplement?

The evidence for saw palmetto is weak. Any benefit reported so far is small and comes from small studies in men with mild to moderate hair loss. It is not a substitute for treatments with more solid evidence, and it has its own side effects.

In any case, before starting any supplement, it is advisable to consult with a dermatologist or hair health professional, as each case is unique, and the treatment should be tailored to the type and degree of hair loss.

References

References Prager, N., Bickett, K., French, N., & Marcovici, G. (2002). A randomized, double-blind, placebo-controlled trial to determine the effectiveness of botanically derived inhibitors of 5-alpha-reductase in the treatment of androgenetic alopecia. The Journal of Alternative and Complementary Medicine, 8(2), 143–152. https://doi.org/10.1089/107555302317371433

Rossi, A., Mari, E., Scarno, M., Garelli, V., Maxia, C., Scali, E., Iorio, A., & Carlesimo, M. (2012). Comparitive effectiveness of finasteride vs Serenoa repens in male androgenetic alopecia: a two-year study. International Journal of Immunopathology and Pharmacology, 25(4), 1167–1173. https://pubmed.ncbi.nlm.nih.gov/23298508/

Wessagowit, V., et al. (2016). Treatment of male androgenetic alopecia with topical products containing Serenoa repens extract. Australasian Journal of Dermatology, 57(3), e76–e82. https://pubmed.ncbi.nlm.nih.gov/26010505/

Bent, S., Kane, C., Shinohara, K., Neuhaus, J., Hudes, E. S., Goldberg, H., & Avins, A. L. (2006). Saw palmetto for benign prostatic hyperplasia. New England Journal of Medicine, 354(6), 557–566. https://doi.org/10.1056/NEJMoa053085

Agbabiaka, T. B., Pittler, M. H., Wider, B., & Ernst, E. (2009). Serenoa repens (saw palmetto): a systematic review of adverse events. Drug Safety, 32(8), 637–647. https://pubmed.ncbi.nlm.nih.gov/19591529/

Firenzuoli, F., et al. (2026). Can we identify a post-Serenoa syndrome (PSS)? A case series on sexual and psychiatric side effects of Serenoa repens. British Journal of Clinical Pharmacology, 92(4), 1237–1246. https://pubmed.ncbi.nlm.nih.gov/41507085/

Cheema, P., El-Mefty, O., & Jazieh, A. R. (2001). Intraoperative haemorrhage associated with the use of extract of Saw Palmetto herb: a case report and review of literature. Journal of Internal Medicine, 250(2), 167–169. https://pubmed.ncbi.nlm.nih.gov/11489067/

National Center for Complementary and Integrative Health. Saw Palmetto (updated April 2025). https://www.nccih.nih.gov/health/saw-palmetto