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Serenoa repens (fruit)

Saw palmetto

Saw palmetto is safe for most men but does little or nothing for the urinary symptoms of an enlarged prostate: a 2023 Cochrane review of 27 trials found little to no difference from placebo, and two large US trials found no benefit even at three times the usual dose. Small trials suggest it may slow male pattern hair loss, but they are too small, and too often built around one company's product, to rely on.

The main caution is not to let it delay a doctor's check of new urinary symptoms, which can have serious causes; a few case reports also link it to bleeding, including raised INR with warfarin.

Updated
10 October 2026
Dark saw palmetto berries in a small bowl beside softgel capsules
At a glance
Last reviewed 10 October 2026
Evidence
Limited
Best for
Enlarged prostate symptoms
Typical form & use
Fruit extract, 320 mg daily
Onset
4+ weeks
Safety
Have urinary symptoms checked by a doctor before using it. 1 known interaction, most serious with blood thinners.
Check with your medications →

What it's used for

Evidence is rated per use. The same ingredient can be strong for one thing and traditional for another.

UseEvidenceWhat the research shows
Enlarged prostate urinary symptomsCompare remedies for men’s health →Compare remedies for bladder & urinary →Limited

A 2023 Cochrane review (27 trials, 4,656 men) found high-certainty evidence that saw palmetto alone makes little to no difference: symptom scores were 0.9 points better than placebo on a 35-point scale at 3 to 6 months and no different at 12 to 17 months.

Two large NIH-funded trials agree: 160 mg twice a day for a year did nothing in 225 men (STEP), and doses rising to 960 mg a day over 72 weeks did no better than placebo in 369 men (CAMUS).

The EU herbal committee still accepts the hexane extract for this use, and a meta-analysis limited to that product (Permixon) found 0.64 fewer night-time trips to the toilet than placebo, but NCCIH reports that the Cochrane reviewers found no difference between hexane and other extracts.1,2,3,4,5,6

Male pattern hair loss (androgenetic alopecia)Compare remedies for hair & nails →Limited

A 2020 systematic review found five small randomised trials and two cohort studies, mostly of products that mixed saw palmetto with other ingredients, taken by mouth (100–320 mg) or applied to the scalp; results were positive but the reviewers said robust data are lacking.

In one 2-year comparison, 38% of men on 320 mg saw palmetto had more hair against 68% on finasteride. A 2026 trial of one proprietary extract in 60 adults reported more hairs than placebo at 6 months. NCCIH says the evidence is too limited for conclusions.7,8,6

Chronic prostatitis / pelvic painLimited

NCCIH reports that a 2022 review of five studies found no significant benefit from saw palmetto for chronic prostatitis or chronic pelvic pain syndrome.6

How much

Ranges below are what studies used and what supplements commonly contain. They are not a recommendation for you. Start at the low end.

Studied range (prostate)
320 mg extract daily4,2
The EU monograph dose for the hexane extract is 320 mg once a day or 160 mg twice a day, and 320 mg once a day for the ethanol extract. The STEP trial used 160 mg twice a day for a year.
Highest dose tested
960 mg extract daily3
The CAMUS trial raised the dose to three times the usual amount over 72 weeks and found no clearly attributable side effects, but also no benefit over placebo.
Hair loss trials
100–320 mg by mouth7
Doses in the hair-loss studies, often combined with other ingredients such as beta-sitosterol; topical products were also tested. No standard dose exists for this use.
Upper limit
None set6
No official upper limit exists. NCCIH says it has been used safely in research studies for up to 3 years.
Timing · Once a day (320 mg) or split into two 160 mg doses, per the EU monograph. The monograph says long-term use is possible.With food? · The EU monograph notes stomach upset, nausea and diarrhoea are more likely when the ethanol extract is taken on an empty stomach, so taking it with food is sensible.How long to trial · Prostate trials judged the effect at 3 to 6 months and again at 12 months or more. The EU monograph says to see a doctor if symptoms persist, worsen, or come with fever, blood in the urine, pain on passing urine or being unable to pass urine.

How people take it

Capsule, hexane extract (e.g. Permixon)320 mg once or 160 mg twice dailyThe form the EU herbal committee accepts as well-established for prostate symptoms. Sold as a licensed medicine in some European countries.
Capsule, ethanol or other extract320 mg once dailyAccepted in the EU on traditional use only. Most supplements do not say how they were extracted, and the Cochrane review found no clear benefit from any extract.
Scalp lotion or serumAs labelledStudied for hair loss only in small trials, often mixed with other ingredients. Reported side effects included a cold or mild burning feeling on the scalp.

Safety

Who should avoid
  • New or worsening urinary symptoms — see a doctor first, as they can have serious causes
  • Pregnancy and breastfeeding — NCCIH says it may be unsafe
  • Children — no relevant use; hot flushes were reported in an 11-year-old girl
  • Warfarin or other blood thinners — a few cases of raised INR reported
  • Planned surgery — one case of severe bleeding during an operation; tell your surgeon
  • Women before the menopause — hot flushes reported, likely hormonal
Known interactions
CautionBlood thinners — The EU monograph records a few suspected cases of raised INR with warfarin, and a case report describes severe bleeding during surgery in a man taking saw palmetto, with a prolonged bleeding time that returned to normal after he stopped.

Questions people ask

Does saw palmetto work for an enlarged prostate?

On the best evidence, no more than a placebo. A 2023 Cochrane review of 27 trials rated it high-certainty that saw palmetto alone makes little to no difference to urinary symptoms or quality of life, and NCCIH concludes it is probably not helpful for this purpose.

Medicines prescribed for an enlarged prostate are a better-tested option to discuss with a doctor.

Is Permixon (hexane-extracted saw palmetto) better than other products?

The EU herbal committee accepts the hexane extract as well-established for prostate symptoms and a meta-analysis limited to Permixon found fewer night-time toilet trips than placebo. But NCCIH reports that the Cochrane reviewers analysed hexane and other extracts separately and found no difference in their effect on symptoms.

Does saw palmetto help with hair loss?

Possibly a little, but the evidence is weak. The trials are small, mostly test mixed products, and NCCIH says the evidence is too limited for conclusions. In one 2-year comparison, finasteride helped more men than saw palmetto (68% against 38%).

Does saw palmetto prevent prostate cancer or affect PSA tests?

There is no evidence that it prevents prostate cancer: in a US cohort of 35,239 men aged 50 to 76, saw palmetto users had the same prostate cancer risk as non-users. NCCIH says it does not appear to change PSA readings, even at higher doses.

Sources (10)

  1. Cochrane systematic review Franco JV, Trivisonno L, Sgarbossa NJ, Alvez GA, Fieiras C, Escobar Liquitay CM, Jung JH. Serenoa repens for the treatment of lower urinary tract symptoms due to benign prostatic enlargement. Cochrane Database Syst Rev. 2023.
  2. Randomised controlled trial Bent S, Kane C, Shinohara K, Neuhaus J, Hudes ES, Goldberg H, Avins AL. Saw palmetto for benign prostatic hyperplasia. N Engl J Med. 2006.
  3. Randomised controlled trial Barry MJ, Meleth S, Lee JY, et al.; CAMUS Study Group. Effect of increasing doses of saw palmetto extract on lower urinary tract symptoms: a randomized trial. JAMA. 2011.
  4. Regulator monograph European Medicines Agency, Committee on Herbal Medicinal Products. European Union herbal monograph on Serenoa repens (W. Bartram) Small, fructus. EMA/HMPC/280079/2013. 2015.
  5. Systematic review and meta-analysis Vela-Navarrete R, Alcaraz A, Rodríguez-Antolín A, et al. Efficacy and safety of a hexanic extract of Serenoa repens (Permixon) for the treatment of lower urinary tract symptoms associated with benign prostatic hyperplasia (LUTS/BPH): systematic review and meta-analysis of randomised controlled trials and observational studies. BJU Int. 2018.
  6. Government fact sheet National Center for Complementary and Integrative Health (NCCIH). Saw Palmetto: Usage and Safety. Last updated April 2025.
  7. Systematic review Evron E, Juhasz M, Babadjouni A, Mesinkovska NA. Natural Hair Supplement: Friend or Foe? Saw Palmetto, a Systematic Review in Alopecia. Skin Appendage Disord. 2020.
  8. Randomised controlled trial Ablon G. The Safety and Efficacy of a Novel Saw Palmetto (Serenoa repens) Extract for Promoting Hair Growth in Adults With Self-Perceived Thinning Hair: 180-Day Results. J Cosmet Dermatol. 2026.
  9. Case report Cheema P, El-Mefty O, Jazieh AR. Intraoperative haemorrhage associated with the use of extract of Saw Palmetto herb: a case report and review of literature. J Intern Med. 2001.
  10. Cohort study Brasky TM, Kristal AR, Navarro SL, Lampe JW, Peters U, Patterson RE, White E. Specialty supplements and prostate cancer risk in the VITamins and Lifestyle (VITAL) cohort. Nutr Cancer. 2011.

Reader notes

Experiences and questions from readers, read by an editor before they appear. They are personal accounts, not evidence, and are not medical advice.

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Last reviewed 10 October 2026 · Next review April 2027 · How we rate evidence