Saw palmetto for hair loss: what the evidence shows

Saw palmetto has a few small studies behind it for hair loss, and none shows it working as well as the FDA-approved options. In the only head-to-head study a 2020 systematic review found, 38% of men taking saw palmetto had more hair growth after 2 years, against 68% taking finasteride (Rossi et al.). The NIH’s National Center for Complementary and Integrative Health says the evidence for male pattern hair loss is too limited to allow conclusions (NCCIH).

Here is what each trial tested and measured, how saw palmetto compares with finasteride, why supplement quality is a real problem, and what to try first.

What saw palmetto is

Saw palmetto is a small tree native to the West Indies and the southeast coast of North America, and its berries have been used for health purposes. It is promoted mainly for urinary symptoms of an enlarged prostate (BPH) and also for male pattern baldness. For BPH, NCCIH says it is probably not helpful: a 2023 review of 27 studies found little or no benefit when it was used alone.

The interest in hair comes from the hormone DHT. Finasteride works by blocking 5-alpha reductase type II, the enzyme that turns testosterone into DHT, which shrinks follicles in pattern hair loss (Propecia label). Saw palmetto extract is described as having anti-androgen properties (Evron et al.), and one trial measured lower blood DHT on it. Having a similar target does not mean it has a similar effect.

The trials, one by one

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Each has a limit that matters. The Prager trial was a 26-man pilot that reported results for 10 men on the active formula, and the formula added beta-sitosterol (Prager et al.). The Rossi study was open label, so patients and doctors knew who took what, and it had no placebo group. The Sudeep trial lasted 16 weeks, found no significant change in the share of hairs in the growth phase, and was run by employees of the company that makes the extract it tested (Sudeep et al.). The Ablon supplement contains saw palmetto among many botanicals, according to the Evron review, so the trial can’t show what saw palmetto added (Ablon and Kogan).

The 2020 systematic review pulled the evidence together: 5 randomized trials and 2 prospective cohort studies, at doses of 100 to 320 mg. Its authors noted that almost all the products tested also contained vitamins, minerals or other ingredients, and listed small samples, missing comparison groups, weak statistics and industry sponsorship among the problems. They called for large trials of saw palmetto on its own.

Saw palmetto vs finasteride

In finasteride’s label trials, 14% of men taking it had further hair loss at 12 months against 58% on placebo, and 35% against 100% at 5 years. Its first-year sexual side effects were uncommon: decreased libido in 1.8% vs 1.3% on placebo, erectile dysfunction in 1.3% vs 0.7%. The label also lists rare reports since approval of depression, suicidal thoughts and sexual problems that continued after stopping. Our finasteride side effects guide covers those in detail.

So the trade is real. Saw palmetto has fewer reported risks, but also far less evidence that it works, and you can’t be sure what dose a given bottle holds.

Saw palmetto for women’s hair loss

No trial has tested saw palmetto alone for female pattern hair loss. The women in the studies above either took a multi-ingredient supplement (Ablon) or were mixed in with men (Sudeep), and the review notes that the trials in women with shedding after stress or illness (telogen effluvium) reported results only qualitatively.

There are also safety questions. NCCIH says saw palmetto may be unsafe during pregnancy or breastfeeding. The Evron review describes hot flashes in premenopausal women and two case reports of girls aged 10 and 11 who had hot flashes on a saw palmetto supplement, then their first period soon after stopping it.

The FDA-approved option for women is minoxidil. Women’s Rogaine 5% foam, used once a day, is sold without a prescription to regrow hair on the top of the scalp; its label says results may show at 3 months and can take at least 6. A clinician can also discuss off-label options such as spironolactone. See minoxidil for women and our best hair loss treatment for women list.

The supplement quality problem

Supplements are regulated differently from drugs. The FDA does not have the authority to approve dietary supplements for safety and effectiveness, or to approve their labels, before they are sold; companies are responsible for that (FDA), and the FDA can act against an adulterated or misbranded product after it reaches the market (FDA). A product sold to treat a disease is legally a drug, even if it is labeled as a supplement.

Saw palmetto has a poor record on dose. When researchers sent 6 saw palmetto products bought in pharmacies and stores for chemical analysis, measured amounts ranged from 97% below to 140% above the label, and 3 contained less than 20% of the stated dose (Feifer et al.). One of 2 brands tested across batches also differed significantly from lot to lot. A separate comparison of 14 brands found significantly different amounts of the fatty acids and other components thought to be active (Habib and Wyllie). The authors concluded that each brand should be judged on its own, so a trial result for one extract may not apply to another.

Side effects

Saw palmetto is well tolerated, according to NCCIH, and has been used safely in research for up to 3 years. Side effects are mild and infrequent: digestive symptoms, dizziness and headache. The review adds nausea, constipation and diarrhea for oral products, and cold sensation, mild burning, itchy scalp, forehead acne and allergic skin reactions for topicals.

If you take any medicine, NCCIH advises talking with your clinician before using an herbal product, because some herbs and medicines interact. The FDA asks anyone who has a reaction to a supplement to stop it, get medical advice and report it to the FDA.

What to try first

Start with the treatments that have FDA approval and larger trials, and give them time: the finasteride label says daily use for 3 months or more is usually needed before a benefit shows, and the women’s foam label says 3 to 6 months.

• Men: oral finasteride, topical minoxidil or both. As of October 2026, Happy Head lists oral finasteride 1 mg at $20 a month ($17 a month on a 12-month supply), compounded to order, so not an FDA-approved product, and MyDrHank lists finasteride from $38 a month. Generic finasteride is listed from $22 a month at Hims and at $25 a month for 30 tablets of 1 mg at Strut Health. Compare prices on our cheapest finasteride online list. See finasteride vs minoxidil for how they compare.
• Women: 5% minoxidil foam once a day, or a clinician visit to discuss off-label options. Finasteride is not approved for women, and in a 12-month study of 137 postmenopausal women it did no better than placebo.
• Either: if you still want saw palmetto, tell your clinician, choose a product whose Supplement Facts label states the extract and amount per serving, and judge it against photos taken before you start.

Compare prescription options on our hair loss providers list, or read about shampoos for hair loss if you want something to add to your routine.

The bottom line

Saw palmetto’s hair loss evidence is a handful of small, short or multi-ingredient studies, and in the only comparison, finasteride did better (68% vs 38% with more hair growth at 2 years). It is mild in side effects but not regulated like a drug, and tests have found some bottles hold a fraction of their stated dose. Try finasteride or minoxidil first; see our hair loss hub to compare providers.