Saw Palmetto (Serenoa repens)

Mechanism of Action

Saw palmetto berry extract contains fatty acids (lauric acid, oleic acid, myristic acid) and phytosterols (beta-sitosterol) that inhibit both isoforms of 5-alpha-reductase (types I and II), reducing conversion of testosterone to dihydrotestosterone (DHT). It also exhibits anti-androgenic activity by competing with DHT at androgen receptor binding sites. Additional mechanisms include: inhibition of cyclooxygenase and 5-lipoxygenase (anti-inflammatory in prostate tissue), induction of apoptosis in prostate epithelial cells, and relaxation of bladder smooth muscle via alpha-1 adrenergic receptor antagonism.

Dosing Protocol

Notes

The Cochrane review evidence for BPH is mixed — early trials (using Permixon) showed benefit, while later, larger trials were less conclusive. Despite this, it remains the most popular natural BPH treatment globally, particularly in Europe where it is prescribed. The DHT-lowering effect has implications for hair loss (androgenetic alopecia) — though evidence for hair regrowth is weaker than for BPH symptom relief. Importantly, saw palmetto can lower PSA levels — inform clients' physicians to avoid masking prostate cancer detection. The sexual side effect profile is generally better than prescription 5-AR inhibitors.

Stacking

• Beta-Sitosterol
• Pygeum
• Zinc
• Stinging Nettle Root (SHBG modulation)

Interactions

• Finasteride/dutasteride (5-AR inhibitors) [MEDIUM] — Additive 5-alpha-reductase inhibition — redundant if on prescription 5-AR inhibitor; may be useful for transition off medication
• Anticoagulants [LOW] — Rare reports of increased bleeding risk (cyclooxygenase inhibition)
• Oral contraceptives/HRT [LOW] — Anti-androgenic effects may interact with hormonal therapies

Contraindications

• Pregnancy (anti-androgenic — teratogenic potential for male fetus)
• Hormone-sensitive conditions (complex hormone modulation)
• Children

Side Effects

• Mild GI discomfort
• Headache
• Dizziness
• Rare: erectile dysfunction (DHT reduction)
• Rare: liver injury (case reports)

Key Papers

• 10.1002/14651858.CD001423.pub3
• 10.1016/j.juro.2011.09.021
• 10.1016/j.eururo.2017.06.023

Source Quality

Liposterolic extract standardized to 85-95% fatty acids and sterols. Permixon (Pierre Fabre) is the most clinically studied extract (used in European trials). CO2 supercritical extraction preserves fatty acid profile. Brands: NOW Saw Palmetto Extract, Jarrow Saw Palmetto, Gaia Herbs. Avoid cheap dried berry powder products (insufficient bioactive concentration).

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