Supplement

Saw Palmetto

Saw palmetto is an extract from the berries of a small palm, thought to slow an enzyme that turns testosterone into DHT and to calm inflammation. Most people look at it for urinary symptoms linked to an enlarged prostate, and the evidence is moderate: across seven studies with about 2,000 people, symptoms eased. The improvement was small, and one study of 32 people found no clear change in DHT.

Sources: PMID 22551330; PMID 12887481

Updated 30 September 2026
How we grade
10 studies cited

Best evidence: Grade B
Conditions studied: 5
Outcomes: 13
Graded outcomes: 0122

Evidence by condition

Strong
Moderate
Limited
Very limited

5 conditions

Benign Prostatic Hyperplasia

Benign Prostatic Hyperplasia: outcomes studied for Saw Palmetto
Grade	Outcome	Effect	Size	Studies	People
	Benign Prostatic Hyperplasia Symptoms Small Improvement	Improves (the measure goes down)	Small effect	7 studies	2,008 people
Studies that measured benign prostatic hyperplasia symptoms Serenoa repens monotherapy for benign prostatic hyperplasia (BPH): an updated Cochrane systematic reviewBJU Int · PMID 22551330 Serenoa repens extract for benign prostate hyperplasia: a randomized controlled trialBJU Int · PMID 12887481 Observational database serenoa repens (DOSSER): overview, analysis and results. A multicentric SIUrO (Italian Society of Oncological Urology) projectArch Ital Urol Androl · PMID 23210402 Saw palmetto for benign prostatic hyperplasiaN Engl J Med · PMID 16467543 Effect of increasing doses of saw palmetto extract on lower urinary tract symptoms: a randomized trialJAMA · PMID 21954478 Improving BPH symptoms and sexual dysfunctions with a saw palmetto preparation? Results from a pilot trialPhytother Res · PMID 22522969 Randomized, double-blind, placebo-controlled trial of saw palmetto in men with lower urinary tract symptomsUrology · PMID 11744467
	Prostate-Specific Antigen No effect		NoneNo effect	1 study	820 people
Studies that measured prostate-specific antigen The effect of increasing doses of saw palmetto fruit extract on serum prostate specific antigen: analysis of the CAMUS randomized trialJ Urol · PMID 23253958
	Quality of Life	Improves (the measure goes up)			451 people
	Sexual Function	Improves (the measure goes up)			902 people
	Testosterone	Improves (the measure goes up)			225 people

Lower Urinary Tract Symptoms

Lower Urinary Tract Symptoms: outcomes studied for Saw Palmetto
Grade	Outcome	Effect	Size	Studies	People
	Benign Prostatic Hyperplasia Symptoms Small Improvement	Improves (the measure goes down)	Small effect	7 studies	85 people
Studies that measured benign prostatic hyperplasia symptoms Serenoa repens monotherapy for benign prostatic hyperplasia (BPH): an updated Cochrane systematic reviewBJU Int · PMID 22551330 Serenoa repens extract for benign prostate hyperplasia: a randomized controlled trialBJU Int · PMID 12887481 Observational database serenoa repens (DOSSER): overview, analysis and results. A multicentric SIUrO (Italian Society of Oncological Urology) projectArch Ital Urol Androl · PMID 23210402 Saw palmetto for benign prostatic hyperplasiaN Engl J Med · PMID 16467543 Effect of increasing doses of saw palmetto extract on lower urinary tract symptoms: a randomized trialJAMA · PMID 21954478 Improving BPH symptoms and sexual dysfunctions with a saw palmetto preparation? Results from a pilot trialPhytother Res · PMID 22522969 Randomized, double-blind, placebo-controlled trial of saw palmetto in men with lower urinary tract symptomsUrology · PMID 11744467
	Prostate-Specific Antigen	Improves (the measure goes up)		1 study	369 people
Studies that measured prostate-specific antigen The effect of increasing doses of saw palmetto fruit extract on serum prostate specific antigen: analysis of the CAMUS randomized trialJ Urol · PMID 23253958

Male Sexual Dysfunction

Benign Prostatic Hyperplasia Symptoms: improves
Quality of Life: improves
Sexual Function: improves

Male Sexual Dysfunction: outcomes studied for Saw Palmetto
Grade	Outcome	Effect	Size	Studies	People
	Benign Prostatic Hyperplasia Symptoms Small Improvement	Improves (the measure goes down)	Small effect	7 studies	82 people
Studies that measured benign prostatic hyperplasia symptoms Serenoa repens monotherapy for benign prostatic hyperplasia (BPH): an updated Cochrane systematic reviewBJU Int · PMID 22551330 Serenoa repens extract for benign prostate hyperplasia: a randomized controlled trialBJU Int · PMID 12887481 Observational database serenoa repens (DOSSER): overview, analysis and results. A multicentric SIUrO (Italian Society of Oncological Urology) projectArch Ital Urol Androl · PMID 23210402 Saw palmetto for benign prostatic hyperplasiaN Engl J Med · PMID 16467543 Effect of increasing doses of saw palmetto extract on lower urinary tract symptoms: a randomized trialJAMA · PMID 21954478 Improving BPH symptoms and sexual dysfunctions with a saw palmetto preparation? Results from a pilot trialPhytother Res · PMID 22522969 Randomized, double-blind, placebo-controlled trial of saw palmetto in men with lower urinary tract symptomsUrology · PMID 11744467
	Quality of Life	Improves (the measure goes up)			82 people
	Sexual Function	Improves (the measure goes up)			82 people

Low Testosterone

DHT
Testosterone: improves

Low Testosterone: outcomes studied for Saw Palmetto
Grade	Outcome	Effect	Size	Studies	People
	DHT No effect		NoneNo effect	1 study	32 people
Studies that measured dht Comparison of finasteride (Proscar) and Serenoa repens (Permixon) in the inhibition of 5-alpha reductase in healthy male volunteersEur Urol · PMID 7805711
	Testosterone	Improves (the measure goes up)			32 people

Hair Loss

Hair Regrowth: improves

Hair Loss: outcomes studied for Saw Palmetto
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Hair Regrowth	Improves (the measure goes up)		1 study	100 people
Studies that measured hair regrowth Comparitive effectiveness of finasteride vs Serenoa repens in male androgenetic alopecia: a two-year studyInt J Immunopathol Pharmacol · PMID 23298508

Key findings

Benign Prostatic Hyperplasia SymptomsImproves (the measure goes down)
Prostate-Specific Antigen
DHTLow Testosterone

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Grade B

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Studies cited

10 studies from PubMed

Serenoa repens monotherapy for benign prostatic hyperplasia (BPH): an updated Cochrane systematic reviewBJU Int · PMID 22551330
Serenoa repens extract for benign prostate hyperplasia: a randomized controlled trialBJU Int · PMID 12887481
Observational database serenoa repens (DOSSER): overview, analysis and results. A multicentric SIUrO (Italian Society of Oncological Urology) projectArch Ital Urol Androl · PMID 23210402
Saw palmetto for benign prostatic hyperplasiaN Engl J Med · PMID 16467543
Effect of increasing doses of saw palmetto extract on lower urinary tract symptoms: a randomized trialJAMA · PMID 21954478
Improving BPH symptoms and sexual dysfunctions with a saw palmetto preparation? Results from a pilot trialPhytother Res · PMID 22522969
Comparitive effectiveness of finasteride vs Serenoa repens in male androgenetic alopecia: a two-year studyInt J Immunopathol Pharmacol · PMID 23298508
Comparison of finasteride (Proscar) and Serenoa repens (Permixon) in the inhibition of 5-alpha reductase in healthy male volunteersEur Urol · PMID 7805711
The effect of increasing doses of saw palmetto fruit extract on serum prostate specific antigen: analysis of the CAMUS randomized trialJ Urol · PMID 23253958
Randomized, double-blind, placebo-controlled trial of saw palmetto in men with lower urinary tract symptomsUrology · PMID 11744467