herb
Saw Palmetto
A liposterolic extract of Serenoa repens berries. Inhibits 5-alpha reductase to reduce DHT conversion, traditionally used to support prostate health and may help with androgenic hair thinning.
What it’s good for
Saw Palmetto for Hair Thinning
Evidence1 study · 1 supporting · 0 against
9 safety notes
Blocks the conversion of testosterone into DHT, the hormone behind pattern hair loss.
Dose: 160–320 mg
Saw Palmetto for Prostate Symptoms
No Benefit4 studies · 0 supporting · 3 against
8 safety notes
How it was tested: One year of saw palmetto extract (160 mg twice daily) produced no significant improvement in symptoms or objective measures (flow rate, prostate size, PSA, QoL, residual volume) vs placebo. This is the STEP trial.
Meant to block the hormone that enlarges the prostate. That has not translated into results.
Dose: 320–960 mg
Tested as: Saw palmetto (Serenoa repens) berry extract. STEP trial used 160 mg twice daily (320 mg/day); CAMUS trial dose-escalated the same 320 mg/day extract to 640 mg/day then 960 mg/day (3x usual dose) over 72 weeks. Neither trial used the hexane-extracted lipidosterolic preparation (Permixon) specifically, and the Cochrane review pooled 27 trials of varying extracts/solvents.
Saw Palmetto for Overactive Bladder
Not verified2 studies · 0 supporting · 0 against
8 safety notes
Why it gets suggested: Proposed to act on the nerve receptors that trigger a bladder squeeze.
Dose: 320 mg
Tested as: Saw palmetto fruit extract, 320 mg/day for 12 weeks, in placebo-controlled trials run in Japanese adults (including a study restricted to women) with self-reported/possible LUTS — not a clinical OAB diagnosis by International Continence Society criteria.
Why we could not verify it: We read the research behind this and none of it concluded that it works for this. That is a finding about the papers, not a verdict that it does nothing.
Saw Palmetto for Acne
Not verified1 study · 0 supporting · 0 against
9 safety notes
Why it gets suggested: Meant to block the hormone signal that drives oil production in the skin.
Dose: 160–320 mg
Why we could not verify it: No human clinical trial, RCT, cohort study, or case report series has tested Serenoa repens (saw palmetto) specifically for acne treatment or sebum reduction. PubMed searches for 'Serenoa repens sebum' and 'saw palmetto acne clinical trial' each return zero results. We cannot stand behind this claim on the evidence we have, so it carries no rating.