Saw Palmetto (Serenoa repens)

Saw palmetto (Serenoa repens) is a small, slow-growing palm native to the southeastern United States, whose berries are harvested for a lipid-rich extract. The primary purpose of this botanical supplement is to modulate androgen metabolism, a property that underlies most of its clinical use, especially for benign-prostatic-hyperplasia (BPH) and related urinary-tract symptoms.

Saw-palmetto extract is a complex mixture; its major phytochemicals include:

• β-Sitosterol (C₂₉H₅₀O) – a plant sterol with a sterol-type tetracyclic ring system and a side-chain alkyl group.
• Stigmasterol (C₂₉H₄₈O) – similar sterol structure with a double bond at C22-C23.

• Lauric, myristic, oleic, and palmitic acids (C₁₂–C₁₈ fatty acids) comprising the lipid fraction.

• The commonly used standardized extract contains ≥ 85 % fatty-acid-free (i.e., sterol-rich) material, with a typical β-sitosterol content of 0.5–1 % (w/w).

• The full extract is a mixture, not a single molecule, so a complete molecular formula does not exist; however, the predominant sterol (β-sitosterol) has the IUPAC name (3β,22E)-Stigmasta-5,22-dien-3-ol.

The raw material is harvested from wild-grown or cultivated Serenoa repens palms in Florida, Georgia, and the Gulf Coast of the United States. Berries are collected in late summer, dried, and then super-critical CO₂ or ethanol-based extraction methods are used to produce a standardized, fatty-acid-free extract. Super-critical CO₂ yields a high-purity sterol fraction with minimal solvent residues, considered the gold-standard for supplement quality.

Quality considerations:

• Standardization to ≥ 85 % fatty-acid-free sterol content is required for clinical comparability.
• Third-party testing (e.g., USP, NSF) for contaminants (heavy metals, pesticides) and verification of sterol content is essential.
• Sustainability: Overharvesting has threatened wild populations; certified “sustainable harvest” or cultivated sources are preferred to ensure ecological integrity.

All statements are based on peer-reviewed literature up to 2024. Users should consult healthcare professionals before initiating any supplementation.