We may earn a commission when you buy through our links, at no extra cost to you. As an Amazon Associate we earn from qualifying purchases. How we make money
At a Glance
- Best evidence A 2023 Cochrane review of 27 studies (4,656 men) found saw palmetto makes little to no difference to urinary symptoms or quality of life compared with placebo1.
- Large US trials The STEP and CAMUS trials, including one at up to three times the usual dose, found no benefit over placebo34.
- Hexane extract A 2018 analysis of one branded hexane extract (Permixon) found fewer night-time trips and better urine flow than placebo5, but Cochrane found no difference by extract type2.
- Safety Generally well tolerated and doesn’t appear to change PSA test results2.
- Top pick NOW Saw Palmetto Extract 320 mg – 320 mg of extract standardized to 85–95% fatty acids, the dose used in most trials, from our guide to the best pumpkin seed oil with saw palmetto supplements.
The Short Answer: Saw palmetto probably doesn’t help urinary symptoms from an enlarged prostate (BPH) much. The 2023 Cochrane review, which looked only at comparisons with placebo, rated the evidence as high certainty: little to no difference in symptoms or quality of life, in the short or long term1. NCCIH concludes it is “probably not helpful” for this2.
On this page
It’s safe for most men, so some still try it for mild symptoms after a doctor’s check. If that’s you, compare products in our guide to the best pumpkin seed oil with saw palmetto supplements, and keep your expectations low.
How Saw Palmetto Is Supposed to Work
Saw palmetto (Serenoa repens) comes from the berries of a small palm native to the southeastern US2. It’s thought to work by blocking 5-alpha reductase, the enzyme that turns testosterone into DHT, which is linked to prostate growth. Prescription drugs such as finasteride work on the same enzyme. For more, see how saw palmetto blocks DHT.
What the Research Shows
| Study | Who and what | Result |
|---|---|---|
| Cochrane review 20231 | 27 studies, 4,656 men; saw palmetto alone or in combinations vs placebo | Little to no difference in symptoms or quality of life (high certainty) |
| STEP 20063 | 225 men; 160 mg twice a day vs placebo; 1 year | No difference in symptoms, urine flow, prostate size or PSA |
| CAMUS 20114 | 369 men; 320 mg rising to 960 mg a day vs placebo; 72 weeks | No better than placebo for any outcome |
| Permixon analysis 20185 | 27 studies of one hexane extract, 5,800 men; trials and observational studies | 0.64 fewer night-time trips and better urine flow than placebo |
| Prostatitis review 20222 | 5 studies of chronic prostatitis/pelvic pain | No significant benefit |
The Cochrane Review
The 2023 Cochrane update compared saw palmetto only with placebo. In the most reliable studies, symptom scores improved by 0.90 points more than placebo after 3–6 months, on a scale from 0 to 35, and by just 0.07 points after 12–17 months. Quality of life didn’t change meaningfully either. Ten of the 27 studies were funded by drug companies1.
The Two Large US Trials
Both trials were funded by the National Institutes of Health2. In STEP, 225 men with moderate to severe symptoms took 160 mg twice a day or placebo for a year, with no difference on any measure, including PSA3. In CAMUS, 369 men took up to three times the usual dose for 72 weeks. Symptom scores fell by 2.20 points on saw palmetto and 2.99 points on placebo4.
Does the Type of Extract Matter?
Some experts argue hexane-extracted products work better. A 2018 meta-analysis of one hexane extract, Permixon, found 0.64 fewer night-time bathroom trips and a 2.75 mL/s better urine flow than placebo, and results similar to tamsulosin5. But it combined randomized trials with observational studies and included only that brand. When the Cochrane reviewers analyzed hexane-extracted products separately, they found no difference from other extracts2.
Our Top Saw Palmetto Pick
NOW Saw Palmetto Extract 320 mg
320 mg extract85–95% fatty acids1 softgel a day
If you still want to try saw palmetto after talking to your doctor, NOW gives 320 mg of extract standardized to 85–95% fatty acids, the daily dose used in most BPH trials, in one softgel. It’s the best standardized extract in our guide to the best pumpkin seed oil with saw palmetto supplements. Don’t expect more than the trials showed.
Saw Palmetto vs Prescription BPH Medicines
Prescription options include alpha-blockers such as tamsulosin and 5-alpha reductase inhibitors such as finasteride and dutasteride. Saw palmetto hasn’t beaten placebo in the best trials134, so it isn’t a substitute for these. Only the Permixon analysis found results similar to tamsulosin, and it has the limits described above5. Talk to your doctor about which option fits your symptoms. For finasteride specifically, see saw palmetto vs finasteride.
Saw Palmetto, PSA and Prostate Cancer Screening
Saw palmetto doesn’t appear to change PSA levels, even at higher doses2. In STEP, PSA didn’t differ from placebo over a year3. Still, tell your doctor you take it before any prostate testing.
Side Effects and Safety
- Common: Side effects are mild and infrequent, such as digestive symptoms, dizziness and headache2. Cochrane found side effects were about as common as on placebo1.
- Long-term use: It has been used safely in studies for up to 3 years2.
- Pregnancy and breastfeeding: May be unsafe2.
- Rare reports: Case reports describe bleeding, pancreatitis and liver injury; see our guide to saw palmetto side effects.
When to See a Doctor
Urinary symptoms can have other causes, including prostate cancer, infection and bladder problems. See a doctor before treating yourself, and right away if you can’t pass urine, see blood in your urine, or have fever or pain.
How Long Does Saw Palmetto Take to Work?
Cochrane found little to no difference from placebo at either 3–6 months or 12–17 months1. If you try it and notice no change after about 3 months, it’s unlikely to help. See how long saw palmetto takes to work.
Final Verdict
The best evidence says saw palmetto doesn’t meaningfully improve BPH symptoms. It’s well tolerated, doesn’t affect PSA and is reasonable to try for mild symptoms if your doctor agrees, but don’t expect much, and don’t use it instead of medical care.
If you decide to try it, use the studied 320 mg dose, such as NOW Saw Palmetto Extract 320 mg. For another option studied for prostate symptoms, see pumpkin seed oil for prostate health, and for other uses, saw palmetto benefits.
Important: This guide is for general information and isn’t medical advice. Get urinary symptoms checked by a doctor before using saw palmetto.
Frequently Asked Questions
Does saw palmetto work for an enlarged prostate?
Does saw palmetto shrink the prostate?
No. In the STEP trial, prostate size didn’t change compared with placebo3.
How much saw palmetto should I take for BPH?
Is saw palmetto better than finasteride or tamsulosin?
Does saw palmetto help prostatitis?
A review of 5 studies found no significant benefit for chronic prostatitis or pelvic pain2.
Is saw palmetto safe to take long term?
It has been used safely in studies for up to 3 years2.
Sources & History
References
- Serenoa repens for the Treatment of Lower Urinary Tract Symptoms Due to Benign Prostatic Enlargement — Cochrane Database of Systematic Reviews, 2023
- Saw Palmetto: Usefulness and Safety — National Center for Complementary and Integrative Health
- Saw Palmetto for Benign Prostatic Hyperplasia — New England Journal of Medicine, 2006
- Effect of Increasing Doses of Saw Palmetto Extract on Lower Urinary Tract Symptoms: A Randomized Trial — JAMA, 2011
- Efficacy and Safety of a Hexanic Extract of Serenoa repens (Permixon) for the Treatment of Lower Urinary Tract Symptoms Associated With Benign Prostatic Hyperplasia: Systematic Review and Meta-Analysis — BJU International, 2018
Update history
- Rewritten with a study table and Cochrane 2023 figures, removed an unverified claim that the 2023 Cochrane review measured prostate size, added the Permixon meta-analysis for balance, and replaced Drugs.com and MSD Manual sources with original studies and NCCIH.
