By ValueReviewHub Editorial · Sources checked September 28, 2026 · How we review
Saw palmetto is the best-selling herbal supplement for prostate health, and the main ingredient in many “prostate support” formulas. It has also been tested in some of the largest supplement trials ever funded by the U.S. National Institutes of Health. The result: the National Center for Complementary and Integrative Health (NCCIH) concludes that saw palmetto is “probably not helpful” for urinary symptoms caused by an enlarged prostate.
Key takeaways
- A 2023 review found that saw palmetto on its own “provides little or no benefit for BPH symptoms” (NCCIH).
- Two major NIH-funded trials, one testing standard doses and one testing doses up to three times higher, found no symptom improvement.
- It is well tolerated and has been used safely in studies for up to 3 years.
- It does not appear to affect PSA readings.
What is saw palmetto?
Saw palmetto (Serenoa repens) is a small palm native to the southeastern United States. Supplements are made from its berries, usually as extracts in capsules. It became popular for prostate symptoms partly because of laboratory research suggesting it might affect hormones involved in prostate growth.
What the clinical trials found
| Evidence | Finding |
|---|---|
| NIH-funded trial of standard dose | No improvement in BPH urinary symptoms compared with placebo |
| NIH-funded trial of escalating doses (up to 3× standard) | Still no improvement compared with placebo |
| 2023 systematic review | Little or no benefit for BPH symptoms when used alone |
Older, smaller studies suggested benefits, which is why many product pages still cite them. Larger and better-designed trials did not confirm those findings. Combination products that pair saw palmetto with other herbs have been less thoroughly studied.
Safety
- Generally well tolerated. It has been used safely in research for up to 3 years.
- Side effects are mild and infrequent, and may include digestive symptoms, dizziness and headache.
- It does not appear to affect PSA levels, which matters for prostate cancer screening.
- If you take other medicines, including blood thinners, check with a pharmacist before adding herbal products.
What to do instead
If you have urinary symptoms, get them evaluated first. Proven treatments for BPH range from lifestyle adjustments to prescription medicines and procedures. Our BPH guide compares the options. If you still want to try saw palmetto, tell your doctor. Don’t let it delay an evaluation, especially if you notice blood in your urine, cannot empty your bladder or have fever with urinary symptoms.
How to read “prostate formula” marketing
- Check whether it cites the large NIH trials or only older, small studies.
- Look for promises to “shrink” the prostate. No over-the-counter supplement has shown this.
- Look for disclosed doses rather than proprietary blends.
- Look for a clear refund policy with no auto-ship subscription.
FAQ
Does saw palmetto help with hair loss or testosterone?
Evidence for these uses is limited. There is no strong evidence that saw palmetto meaningfully raises testosterone. See do testosterone boosters work?
Is saw palmetto safe to take long term?
It was well tolerated for up to 3 years in studies. Discuss any long-term supplement with your doctor.
Related reading
- Enlarged prostate (BPH) guide
- Do testosterone boosters work?
- Zinc for men
- Male enhancement supplements: hidden drug warnings
Sources
Medical note: This article is general education, not medical advice. Talk to your doctor or pharmacist before starting a supplement, especially if you take medication, are pregnant or breastfeeding, or have a health condition. Read our medical disclaimer.