Saw Palmetto for 5-Alpha Reductase Inhibition

Saw palmetto is the most-studied botanical marketed for DHT control. The best-conducted trials (STEP and CAMUS) found it no better than placebo for prostate symptoms, while smaller studies report small benefits.

Overview

Verdict

Mixed evidence

Saw palmetto may modestly ease urinary symptoms, but controlled trials show little consistent reduction in serum DHT.

How It Works

Fatty acids and sterols in the liposterolic extract inhibit 5-alpha reductase in vitro and may have anti-inflammatory and alpha-adrenergic effects in prostate tissue.

Dosing & Protocol

Typical dose

Recommended dose: 320 mg/day standardized liposterolic extract
Expected timeframe: 12 weeks minimum before judging any effect

Protocol

form: Liposterolic Serenoa repens extract standardised to 85-95% fatty acids and sterols; Permixon is the best-studied preparation
duration: 6-12 months in the relevant trials
co factor: Take with food. Evidence is mixed. Saw palmetto fatty acids inhibit both type 1 and type 2 5-alpha-reductase in cell-free and cell culture systems, which is a real and reproducible in vitro finding and the basis of its entire commercial positioning. Translation to humans is where it fails: the NIH-funded STEP and CAMUS trials found no significant reduction in serum or intraprostatic DHT even at 960 mg/day, and no clinical benefit over placebo for prostate symptoms. Some small studies report modest intraprostatic DHT reduction. The plausible explanation is that tissue concentrations achievable orally are far below those used in vitro.
titration: 320 mg/day is standard; the CAMUS trial escalated to 960 mg/day without benefit
starting dose: 160 mg twice daily with food if used

Evidence

What the studies say

The NIH-funded STEP trial (225 men) and CAMUS trial (369 men, doses up to 960 mg/day) both found no significant advantage over placebo on urinary symptom scores. Earlier Cochrane analyses that suggested benefit were downgraded once higher-quality trials were included. Serum DHT changes are generally small or absent.

Comparitive effectiveness of finasteride vs Serenoa repens in male androgenetic alopecia: a two-year study

Score: 5/10

2012

rct

n=100

Rossi A

38% of patients treated with Serenoa repens had an increase in hair growth, while 68% of those treated with finasteride noted an improvement.

View source

A randomized, double-blind, placebo-controlled trial to determine the effectiveness of botanically derived inhibitors of 5-alpha-reductase in the treatment of androgenetic alopecia

Score: 4/10

2002

rct

n=26

Botanically derived 5AR inhibitors were tested in a placebo-controlled, double-blind study in androgenetic alopecia.

View source

Safety

Caveats

Does not replace finasteride or dutasteride. Can cause mild GI upset. Herb quality and extract standardization vary widely.

Less likely to help if

Men with large prostate volume or moderate-to-severe obstruction rarely respond; they need pharmacologic or urologic care.

Medical Disclaimer

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Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.