Saw Palmetto
Serenoa repens (Saw Palmetto)
Saw palmetto is a palm plant extract (Serenoa repens) standardized to 85-95% fatty acids and sterols, primarily used for the management of benign prostatic hyperplasia (BPH) symptoms and androgenic alopecia. It is one of the most widely studied botanical supplements for urinary symptoms associated with prostate enlargement, including urinary frequency, weak stream, and nocturia.
Mechanism of Action
Saw palmetto inhibits both isoforms (Type I and Type II) of 5-alpha-reductase, the enzyme responsible for converting testosterone to the more potent dihydrotestosterone (DHT), thereby reducing DHT-mediated stimulation of prostate tissue growth. It also exhibits anti-inflammatory effects by inhibiting COX-1/COX-2 pathways and may exert weak anti-estrogenic and alpha-adrenergic receptor antagonist activity, collectively contributing to its effects on prostate tissue and hair follicles.
Evidence by Health Goal(17 goals)
Dosing Protocols
With meals to improve absorption and reduce gastrointestinal side effects
Standardized extract containing 85-95% fatty acids is required for clinical efficacy; non-standardized whole berry products are unlikely to provide equivalent benefit. Effects typically require 4-8 weeks of consistent use before symptomatic improvement is observed.
Safety & Side Effects
Saw palmetto has a generally favorable safety profile with decades of use and multiple clinical trials supporting tolerability; however, it should be discontinued at least two weeks before surgery due to antiplatelet activity, and men with prostate concerns should have PSA levels and prostate health evaluated by a physician before use as the supplement may modestly reduce PSA values, potentially masking prostate cancer screening results.
Possible Side Effects
- !Mild gastrointestinal discomfort, nausea, or diarrhea (most common, especially without food)
- !Headache, particularly during initial use
- !Dizziness or orthostatic hypotension at higher doses
- !Decreased libido or erectile dysfunction (reported in a minority of users)
- !Breast tenderness or gynecomastia (rare, due to hormonal modulation)
- !Elevated bleeding risk, particularly perioperatively
- !Hepatotoxicity (very rare, case reports only)
Interactions
- -May potentiate anticoagulants and antiplatelet drugs (warfarin, aspirin, clopidogrel) — increased bleeding risk
- -Additive DHT-lowering effects when combined with finasteride or dutasteride — monitor for exaggerated hormonal side effects
- -May interfere with hormonal contraceptives or hormone replacement therapy due to anti-estrogenic and anti-androgenic activity
- -Can modestly reduce serum PSA levels — may confound prostate cancer screening if not disclosed to clinician
- -Potential additive hypotensive effect when combined with alpha-blocker medications (tamsulosin, doxazosin)
Cost & Where to Buy
Cost varies significantly by standardization quality; products standardized to 85-95% fatty acids from reputable brands (e.g., Nature's Way, NOW Foods, Jarrow) cost more than non-standardized formulations but are necessary for clinical relevance.
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