Does Saw Palmetto Work for Hair Loss and Block DHT?

Somewhat. Saw palmetto produces small gains in hair count and density in pattern hair loss, but it is clearly weaker than finasteride. In the only long head-to-head study, about 4 in 10 men improved on saw palmetto over 2 years, against about 7 in 10 on finasteride. It does appear to lower DHT, the hormone that shrinks hair follicles, but by much less than the prescription drugs.

Saw palmetto is an extract from the berries of a small palm, Serenoa repens. It is sold as a natural alternative to finasteride for androgenetic alopecia, the medical name for male and female pattern hair loss. The evidence behind it is a handful of small trials, several testing branded extracts, and three reviews that pool them.

What the Data Show

A 2020 systematic review found 5 randomized trials and 2 prospective studies of oral and topical products containing 100 to 320 mg of saw palmetto. All of them reported some benefit in pattern hair loss or telogen effluvium, a temporary shedding after stress or illness. The authors also wrote that high-quality data are lacking and called for larger trials testing saw palmetto on its own, because many of the products mixed it with other ingredients.

A larger 2025 network meta-analysis pooled 19 randomized trials of hair supplements with 1,658 people. Saw palmetto extract scored better than placebo when doctors who did not know the treatment rated hair regrowth from photos. It was not among the supplements shown to raise measured hair density. Pumpkin seed oil, apple extract, tocotrienols and a branded multi-ingredient product made that list.

A 2026 network meta-analysis of off-label treatments in men compared the change in hair density over 6 months. Topical minoxidil 5% ranked most effective. Topical saw palmetto was among the other treatments that showed a benefit.

Two placebo-controlled trials give a sense of the size of the effect. In a 16-week trial of 80 men and women, a standardized saw palmetto oil raised hair density by 5.17% when taken by mouth and 7.61% when applied to the scalp, and cut hair fall by up to 29% and 22%, measured against each person’s starting point. Four of its six authors worked for Vidya Herbs, the company that makes the extract.

In a 6-month trial of 60 adults with thinning hair, terminal hair count rose by an average of 18.6 hairs on a proprietary extract and fell by 10.1 on placebo. Terminal hairs are the thick, pigmented hairs, as opposed to fine vellus “peach fuzz” hairs.

The earliest trial was a placebo-controlled pilot in men aged 23 to 64. Six of the 10 men taking saw palmetto with beta-sitosterol, a plant sterol, were rated as improved by blinded staff.

Does Saw Palmetto Block DHT?

Partly. Pattern hair loss is driven by DHT (dihydrotestosterone), a stronger form of testosterone. An enzyme called 5-alpha reductase makes DHT from testosterone in the scalp and prostate, and over years DHT shrinks hair follicles in people who are genetically prone to it. Finasteride and dutasteride work by blocking that enzyme.

Saw palmetto is described as a botanical 5-alpha reductase inhibitor, and it has been shown to inhibit both types of the enzyme in laboratory work. In people, one randomized trial found that oral saw palmetto oil lowered blood DHT compared with placebo.

How much it lowers DHT matters, and here the prostate research is telling. Finasteride lowers PSA, a protein made by the prostate, because it cuts DHT so sharply. In a large randomized trial of 369 men, saw palmetto at up to 960 mg a day for 72 weeks did not change PSA any more than placebo. That points to a much weaker effect on DHT than the prescription drugs.

Saw Palmetto vs Finasteride for Hair Loss

The one long comparison was a 2-year study of 100 men with mild to moderate pattern hair loss. Half took saw palmetto 320 mg a day and half took finasteride 1 mg a day. On photo scoring, 38% of the saw palmetto group had more hair at the end, against 68% of the finasteride group. Finasteride helped both the front and the crown, while saw palmetto worked mostly at the crown. The study was open label, meaning everyone knew what they were taking.

	Saw palmetto 320 mg/day	Finasteride 1 mg/day
Men with more hair at 2 years	38%	68%
Where it helped	Mostly the crown	Front and crown
Regulated as	Dietary supplement	Prescription drug

Topical vs Oral Saw Palmetto

Both forms show modest benefit, and no trial shows one clearly beating the other. In the 16-week four-arm trial, the scalp formula raised density slightly more (7.61% vs 5.17%) and the capsule cut hair fall slightly more (29% vs 22%).

In an uncontrolled study of 50 men using topical saw palmetto products, hair counts were up at 12 and 24 weeks. Some of the gains levelled off after the concentrated product was stopped at week 4, which suggests a topical needs to be used continuously. Topical saw palmetto in men also showed a benefit in the 2026 pooled analysis, ranked below minoxidil.

How Long Does Saw Palmetto Take to Work for Hair?

Plan on at least 3 to 6 months. Hair grows slowly, and that is the length of the trials. Topical counts were up by week 12, the capsule trial measured results at 16 weeks, and the placebo-controlled extract trial ran 6 months. The finasteride comparison ran 2 years.

The usual oral dose in the trials was 320 mg a day, and the products in the 2020 review ranged from 100 to 320 mg. Like any treatment for pattern hair loss, the benefit lasts only as long as you keep using it.

Is Saw Palmetto Safe? Side Effects, Shedding and PSA

For most people, yes. A systematic review of 40 studies found side effects were mild and similar to placebo. The most common were stomach pain, diarrhea, nausea, tiredness, headache, lower sex drive and a runny nose. Serious events showed up only in isolated case reports, and the authors judged the link to saw palmetto doubtful.

The best long safety data come from the CAMUS trial. Men took 320, 640 and then 960 mg a day for 18 months. There were no differences from placebo in side effects, vital signs, lab tests or dropouts, even at 3 times the usual dose.

PSA. Older reviews, including the 2009 review this page first covered, warned that saw palmetto could lower PSA and hide an early prostate cancer. The CAMUS PSA analysis tested that directly and found PSA rose by 0.23 ng/ml on saw palmetto and 0.16 ng/ml on placebo, a difference that was not significant. Still tell your doctor about any supplement before a PSA test.

Shedding. None of the trials I reviewed reported an early shedding phase. In the 16-week trial, hair fall went down, not up.

Does Saw Palmetto Work for Women?

There is less data, but one trial is encouraging. In the 6-month placebo-controlled trial, women past menopause gained terminal hair count and hair density compared with placebo. The 16-week trial also enrolled women aged 18 to 50. Because saw palmetto acts on male hormones, it is not a supplement for pregnancy or for anyone trying to conceive.

Dr. Kumar’s Take

Saw palmetto is not a scam, and it is not finasteride. The trials point the same way: a small gain in hair, little risk, and a much weaker hormone effect than the drug it is marketed against. The catch is that the strongest positive trials used branded extracts, one was run largely by the extract’s maker, and the bottles on store shelves vary widely in what they contain.

For someone who will not take finasteride, it is a reasonable thing to try for 6 months, with photos taken in the same light at the start so the result can be judged honestly. For someone losing hair quickly, the time spent on a weak option is hair that may not come back.

Free guide: I put the complete, evidence-based plan into The Hair Loss Protocol, a downloadable guide you can take to your doctor.

Practical Takeaways

Expect a modest effect. About 4 in 10 men improved over 2 years, against about 7 in 10 on finasteride.
The trial dose was 320 mg a day by mouth. Topical products also showed small gains.
Give it 3 to 6 months before judging it, and take dated photos at the start.
Combine, don’t substitute, if your hair loss is moving fast. Topical minoxidil 5% ranked first among non-pill options in men.
Side effects are uncommon and mild, mostly stomach upset. Taking it with food may help.
Avoid it in pregnancy and if trying to conceive.
Tell your doctor you take it, especially before prostate testing or surgery.

FAQs

Is saw palmetto a DHT blocker?

It is a weak one. One trial found oral saw palmetto oil lowered blood DHT compared with placebo. But in a large prostate trial, even high doses did not lower PSA, which finasteride does, so its effect on DHT is far smaller than the drug’s.

Does saw palmetto regrow hair?

It can produce a small amount of regrowth. Trials found gains in hair count and density of a few percent over 4 to 6 months. In a 2-year study, 38% of men had more hair on saw palmetto, compared with 68% on finasteride.

Is topical or oral saw palmetto better?

Neither has been shown to be clearly better. In one trial the scalp formula raised density a bit more, while the capsule cut hair fall a bit more. Topical products seem to need continuous use to keep their effect.

Does saw palmetto cause hair shedding?

None of the trials reviewed here reported an early shedding phase. In a 16-week placebo-controlled trial, hair fall dropped by up to 29% on the oral form.

Does saw palmetto affect PSA?

Not in the best trial. Men taking up to 960 mg a day for 72 weeks had PSA changes no different from placebo. Tell your doctor you take it anyway, so every result is read with the full picture.

Bottom Line

Saw palmetto gives a small, real boost to hair in pattern hair loss, with few side effects, but it is clearly weaker than finasteride and lowers DHT far less. The usual trial dose is 320 mg a day by mouth, and topical forms help about as much. Give it 3 to 6 months, track it with photos, and if hair loss is moving fast, do not let it stand in for treatments that work better.

Does Saw Palmetto Work for Hair Loss and Block DHT?