herb

Saw Palmetto

Also known as Serenoa repens

Berry extract that inhibits 5-alpha-reductase, the enzyme converting testosterone to DHT; used for benign prostatic hyperplasia symptoms and androgenic hair thinning, though large trials show mixed results versus placebo.

Reported side effects:Digestive symptoms (mild and infrequent)DizzinessHeadache

Be careful if: pregnant, breastfeeding, some medical situations

Suspect a side effect? Report it to the MHRA Yellow Card scheme ↗

2linked conditions

17linked studies

On this pageWhat studies found Safety Evidence Availability Outcomes & conditions →

Evidence

What the research actually shows

We link to relevant studies and leave interpretation to you and your healthcare professional.

What studies found

The headline results, condition by condition

The large figures are what the studies reported for each thing they measured. Open a card for every result.

Colour keyReported a benefitNo clear benefitUnclearPossible harmAmber is for highlights, such as where the most research is. It never means a result was good.

Prostate Health

1 of 14 results reported a benefit

4 studies, including a review of trials

Prostate sizeNo clear difference1.22 cc lower1 review of trials2012 study ↗
Urinary symptomsNo clear difference0.25 points higher1 review of trials0 of 4 results reported a benefit2012 study ↗
Peak urine flowNo clear difference0.4 mL/s higher1 review of trials0 of 2 results reported a benefit2012 study ↗

No figure given: Night-time urination (no clear benefit).

Also measured alongside: Prostate-related quality of life (reported a benefit); Quality of life (no clear benefit); Prostate blood marker (PSA) (no clear benefit).

2 more measures

Safety

Safety and considerations

What sources report about side effects, who should be careful, and medicines to ask about first.

Reported side effects

Reported effect	How often	Basis	Sources
Digestive symptoms (mild and infrequent)	unknown	Listed by NIH ODS fact sheets	NIH NCCIH fact sheet: Saw Palmetto
Dizziness	unknown	Listed by NIH ODS fact sheets	NIH NCCIH fact sheet: Saw Palmetto
Headache	unknown	Listed by NIH ODS fact sheets	NIH NCCIH fact sheet: Saw Palmetto
Decreased libido (corpus row)	unknown	Listed by PubMed corpus rows (PubMed 32274957)	Systematic review/meta-analysis of Serenoa repens adverse events (corpus row), PMID 32274957
Ejaculation disorders (corpus row)	unknown	Listed by PubMed corpus rows (PubMed 32274957)	Systematic review/meta-analysis of Serenoa repens adverse events (corpus row), PMID 32274957

Be careful if you…

Applies to	What sources say	Sources
pregnant	Saw palmetto may be unsafe during pregnancy (NCCIH).	NIH NCCIH fact sheet: Saw Palmetto
breastfeeding	Saw palmetto may be unsafe while breastfeeding (NCCIH).	NIH NCCIH fact sheet: Saw Palmetto
some medical situations	Saw palmetto does not appear to affect PSA readings, even at higher-than-usual amounts (NCCIH) — this contradicts the legacy note about falsely lowered PSA. Men having prostate monitoring should still tell their urologist they take it.	NIH NCCIH fact sheet: Saw Palmetto

Sources

NIH NCCIH fact sheet: Saw Palmetto Systematic review/meta-analysis of Serenoa repens adverse events (corpus row), PMID 32274957

Evidence analytics

Where the evidence is concentrated

Audited published research for Saw Palmetto by condition. Drill into a pair page for the full breakdown.

Published research

Saw Palmetto: findings by condition

What this means: Bars count reported findings, not treatment effectiveness or certainty.

One study may report several findings or appear in more than one pairing. Counts do not show the size of an effect. Comparable numerical estimates are not established for this summary.

View the full data table

Published research: reported directions by pairing
Compound and condition	Findings (count)	Studies (count)	Reported results (finding counts)	How sure?
Prostate Health	17	4	Benefit: 3; no benefit: 14; harm: 0; unclear: 0; not recorded / unrecognised: 0	Not formally graded

Suggested uses (unproven)

Where people report using it and what trials suggest

Mixed evidenceBPH urinary symptoms

Where the evidence is negative

Common claims the trials do not support

STEP (n=225) and CAMUS (n=369, up to 3x dose): no benefit vs placebo at any dose.
Guidelines do not recommend it for LUTS/BPH.

Prostate herb that failed its large definitive trials; a cautionary tale for herbal urology claims.

Evidence grades reflect study quality and consistency, not marketing claims.

17studies referenced

15journals

1999–2026publication range

Ordered by strength of evidence, then result direction.

01Pathophysiology, conventional treatments, and evidence-based herbal remedies of hair loss with a systematic review of controlled clinical trialsAllam AT, et al. · Naunyn-Schmiedeberg's archives of pharmacology · 2025PMID 40536553 ↗02Effects of dietary supplements on androgenetic alopecia: a systematic review and network meta-analysisZhou L, et al. · Frontiers in nutrition · 2025PMID 41561175 ↗03Serenoa repens for the treatment of lower urinary tract symptoms due to benign prostatic enlargement: A systematic review and meta-analysisTrivisonno LF, et al. · Investigative and clinical urology · 2021PMID 34488251 ↗04Comparison of Serenoa repens With Tamsulosin in the Treatment of Benign Prostatic Hyperplasia: A Systematic Review and Meta-AnalysisCai T, et al. · American journal of men's health · 2020PMID 32274957 ↗05Benign prostate hyperplasia and nutritionDas K, et al. · Clinical nutrition ESPEN · 2019PMID 31451276 ↗06Serenoa repens for benign prostatic hyperplasiaTacklind J, et al. · The Cochrane database of systematic reviews · 2012PMID 23235581 ↗

Show all 17 studies

07American palm ethnomedicine: a meta-analysisSosnowska J, et al. · Journal of ethnobiology and ethnomedicine · 2009PMID 20034398 ↗08Phytotherapy for benign prostatic hyperplasiaWilt TJ, et al. · Public health nutrition · 2000PMID 11276294 ↗09Unsafe and potentially safe herbal therapiesKlepser TB, et al. · American journal of health-system pharmacy : AJHP : official journal of the American Society of Health-System Pharmacists · 1999PMID 10030529 ↗10The Safety and Efficacy of a Novel Saw Palmetto (Serenoa repens) Extract for Promoting Hair Growth in Adults With Self-Perceived Thinning Hair: 180-Day ResultsAblon G · Journal of cosmetic dermatology · 2026PMID 41652806 ↗11Beneficial effects of saw palmetto (Serenoa repens) fruit extract on the urinary symptoms of healthy Japanese adults with possible lower urinary tract symptoms: A randomized, double-blind, placebo-controlled studyKimura M, et al. · Nutrition and health · 2025PMID 39042923 ↗12Impact of a Novel Dietary Supplement on Efficacy of Pharmacological Treatments for Androgenic Alopecia: A Real-Life, Multicenter, Randomized, Assessor-Blinded Trial on 225 SubjectsMilani M, et al. · Journal of cosmetic dermatology · 2025PMID 40853071 ↗13The Safety and Efficacy of a Proprietary Bioactive Fatty Acids Extract From Saw Palmetto (Serenoa repens) for Promoting Hair Growth and Reducing Hair Loss in Adults With Self-Perceived Thinning Hair: 90-Day ResultsAblon G · Journal of cosmetic dermatology · 2025PMID 41319217 ↗14A preliminary study on topical cetirizine in the therapeutic management of androgenetic alopeciaRossi A, et al. · The Journal of dermatological treatment · 2018PMID 28604133 ↗15Saw Palmetto for Symptom Management During Radiation Therapy for Prostate CancerWyatt GK, et al. · Journal of pain and symptom management · 2016PMID 26891611 ↗16Comparitive effectiveness of finasteride vs Serenoa repens in male androgenetic alopecia: a two-year studyRossi A, et al. · International journal of immunopathology and pharmacology · 2012PMID 23298508 ↗17A randomized, double-blind, placebo-controlled trial to determine the effectiveness of botanically derived inhibitors of 5-alpha-reductase in the treatment of androgenetic alopeciaPrager N, et al. · Journal of alternative and complementary medicine (New York, N.Y.) · 2002PMID 12006122 ↗

Search PubMed ↗View on PubChem ↗Find clinical trials ↗

Published research results

Reported results grouped by condition. Values and units are preserved as recorded; missing information is not estimated.

How to read this table

Benefit: What the trial saw happen: whether the measured outcome moved in the helpful direction in that one study (the tag on each row: “Benefit seen”, “No clear benefit”, “Possible harm” or “Unclear”). It is a study result — not advice, and not a promise it will work for you.
Evidence: Study design describes how research was conducted. It is not a formal certainty assessment.
Effect size: The result recorded in this summary. “Not reported” means the value is missing from the summary; it does not establish that the publication omitted it.

Reported direction, numerical results and study design are separate. Certainty has not been formally graded in this table.

Prostate Health (17 outcomes)

Published research: Prostate Health
What was measured	Reported findings	Result and units	Reported sample and duration	Study / source
adverse events	Serenoa repens showed little to no difference in adverse events versus placebo in 4,853 participants over short- and long-term follow-up.No clear benefit	Not reported Recorded unit: Not reported	Sample (as reported): 4,853 Follow-up: short- and long-term follow-up	Meta-analysis · 2021 Study details Serenoa repens for the treatment of lower urinary tract symptoms due to benign prostatic enlargement: A systematic review and meta-analysis. Meta-Analysis PMID 34488251
quality of life	Serenoa repens showed little to no difference in quality of life versus placebo in 4,853 participants over short- and long-term follow-up.No clear benefit	Not reported Recorded unit: Not reported	Sample (as reported): 4,853 Follow-up: short- and long-term follow-up	Meta-analysis · 2021 Study details Serenoa repens for the treatment of lower urinary tract symptoms due to benign prostatic enlargement: A systematic review and meta-analysis. Meta-Analysis PMID 34488251
urinary symptoms score	Serenoa repens showed little to no difference in urinary symptoms versus placebo in 4,853 participants over short- and long-term follow-up.No clear benefit	Not reported Recorded unit: Not reported	Sample (as reported): 4,853 Follow-up: short- and long-term follow-up	Meta-analysis · 2021 Study details Serenoa repens for the treatment of lower urinary tract symptoms due to benign prostatic enlargement: A systematic review and meta-analysis. Meta-Analysis PMID 34488251
Decreased libido	Serenoa repens had fewer cases of decreased libido compared with tamsulosin (OR 5.40) in 1,080 patients over at least 6 months. (95% CI [1.17, 24.87]; p = 0.03)Benefit seen	5.40 Recorded unit: Not reported	Sample (as reported): 1,080 Follow-up: at least 6-month treatment cycle	Meta-analysis · 2020 Study details Comparison of Serenoa repens With Tamsulosin in the Treatment of Benign Prostatic Hyperplasia: A Systematic Review and Meta-Analysis. Meta-Analysis PMID 32274957
Ejaculation disorders	Serenoa repens had fewer ejaculation disorders compared with tamsulosin (OR 12.56) in 1,080 patients over at least 6 months. (95% CI [3.83, 41.18], p < 0.0001)Benefit seen	12.56 Recorded unit: Not reported	Sample (as reported): 1,080 Follow-up: at least 6-month treatment cycle	Meta-analysis · 2020 Study details Comparison of Serenoa repens With Tamsulosin in the Treatment of Benign Prostatic Hyperplasia: A Systematic Review and Meta-Analysis. Meta-Analysis PMID 32274957
International Prostate Symptom Score (IPSS)	Serenoa repens showed no significant difference in IPSS compared with tamsulosin (MD 0.63) in 1,080 patients over at least 6 months. (95% CI [-0.33, 1.59], p = 0.20)No clear benefit	0.63 Recorded unit: Not reported	Sample (as reported): 1,080 Follow-up: at least 6-month treatment cycle	Meta-analysis · 2020 Study details Comparison of Serenoa repens With Tamsulosin in the Treatment of Benign Prostatic Hyperplasia: A Systematic Review and Meta-Analysis. Meta-Analysis PMID 32274957
Maximum flow rate (Qmax)	Serenoa repens showed no significant difference in Qmax compared with tamsulosin (MD 0.27) in 1,080 patients over at least 6 months. (95% CI [-0.15, 0.68], p = 0.21)No clear benefit	0.27 Recorded unit: Not reported	Sample (as reported): 1,080 Follow-up: at least 6-month treatment cycle	Meta-analysis · 2020 Study details Comparison of Serenoa repens With Tamsulosin in the Treatment of Benign Prostatic Hyperplasia: A Systematic Review and Meta-Analysis. Meta-Analysis PMID 32274957
Postvoid residual volume (PVR)	Serenoa repens showed no significant difference in PVR compared with tamsulosin (MD -4.23) in 1,080 patients over at least 6 months. (95% CI [-22.97, 14.44], p = 0.65)No clear benefit	-4.23 Recorded unit: Not reported	Sample (as reported): 1,080 Follow-up: at least 6-month treatment cycle	Meta-analysis · 2020 Study details Comparison of Serenoa repens With Tamsulosin in the Treatment of Benign Prostatic Hyperplasia: A Systematic Review and Meta-Analysis. Meta-Analysis PMID 32274957
Prostate-specific antigen (PSA)	Serenoa repens showed no significant difference in PSA compared with tamsulosin (MD 0.46) in 1,080 patients over at least 6 months. (95% CI [-0.06, 0.97], p = 0.08)No clear benefit	0.46 Recorded unit: Not reported	Sample (as reported): 1,080 Follow-up: at least 6-month treatment cycle	Meta-analysis · 2020 Study details Comparison of Serenoa repens With Tamsulosin in the Treatment of Benign Prostatic Hyperplasia: A Systematic Review and Meta-Analysis. Meta-Analysis PMID 32274957
Quality of Life (QoL)	Serenoa repens showed no significant difference in QoL compared with tamsulosin (MD 1.51) in 1,080 patients over at least 6 months. (95% CI [-1.51, 4.52], p = 0.33)No clear benefit	1.51 Recorded unit: Not reported	Sample (as reported): 1,080 Follow-up: at least 6-month treatment cycle	Meta-analysis · 2020 Study details Comparison of Serenoa repens With Tamsulosin in the Treatment of Benign Prostatic Hyperplasia: A Systematic Review and Meta-Analysis. Meta-Analysis PMID 32274957
Clinical response	Saw palmetto did not increase clinical response compared to placebo; response rates were 42.6% and 44.2%, respectively. (95% CI 0.76 to 1.22)No clear benefit	0.96 risk ratio Recorded unit: Not reported	Sample (as reported): Not reported Follow-up: Not reported	Meta-analysis · 2012 Study details Serenoa repens for benign prostatic hyperplasia. Meta-Analysis PMID 23235581
Nightly urination	Saw palmetto did not significantly decrease nightly urination compared to placebo. (P = 0.19)No clear benefit	Not reported Recorded unit: Not reported	Sample (as reported): Not reported Follow-up: Not reported	Meta-analysis · 2012 Study details Serenoa repens for benign prostatic hyperplasia. Meta-Analysis PMID 23235581
Peak urine flow	Saw palmetto did not significantly improve peak urine flow compared to placebo. (95% CI -0.30 to 1.09)No clear benefit	0.40 mL/s Recorded unit: mL/s	Sample (as reported): Not reported Follow-up: Not reported	Meta-analysis · 2012 Study details Serenoa repens for benign prostatic hyperplasia. Meta-Analysis PMID 23235581
Prostate size	Saw palmetto did not significantly reduce prostate size compared to placebo. (95% CI -3.91 to 1.47)No clear benefit	-1.22 cc Recorded unit: cc	Sample (as reported): Not reported Follow-up: Not reported	Meta-analysis · 2012 Study details Serenoa repens for benign prostatic hyperplasia. Meta-Analysis PMID 23235581
Urinary symptoms	Saw palmetto did not improve urinary symptom scores compared to placebo; the mean difference was 0.25 points. (95% confidence interval (CI) -0.58 to 1.07)No clear benefit	0.25 points Recorded unit: points	Sample (as reported): Not reported Follow-up: Not reported	Meta-analysis · 2012 Study details Serenoa repens for benign prostatic hyperplasia. Meta-Analysis PMID 23235581
Functional Assessment of Cancer Therapy-Prostate prostate-specific concerns score	Prostate-specific concerns improved in the saw palmetto group compared to placebo in 21 men over 22 weeks (P = 0.03). (P = 0.03)Benefit seen	Not reported Recorded unit: Not reported	Sample (as reported): 21 Follow-up: 22 weeks	Randomised trial · 2016 Study details Saw Palmetto for Symptom Management During Radiation Therapy for Prostate Cancer. Randomized Controlled Trial PMID 26891611
International Prostate Symptom Score	No significant difference in symptom scores was found between saw palmetto and placebo in 21 men over 22 weeks.No clear benefit	Not reported Recorded unit: Not reported	Sample (as reported): 21 Follow-up: 22 weeks	Randomised trial · 2016 Study details Saw Palmetto for Symptom Management During Radiation Therapy for Prostate Cancer. Randomized Controlled Trial PMID 26891611

Important: This page reflects observational, aggregate-only community reporting and independent published research. It is not medical advice, and it does not claim any compound treats, cures, or is effective for any condition. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or treatment.

Outcomes & conditions

Why people look into Saw Palmetto — and what they report

Associated conditions and community-reported outcomes, wrapped together on one page. Aggregates appear only once enough reports arrive.

Outcomes & conditions →

Availability

Where to get Saw Palmetto (UK)

How this compound is sold in the UK, and where our readers typically find it.

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