Saw Palmetto

Saw palmetto extract is derived from the ripe fruit of Serenoa repens, also called Sabal serrulatum, a slow-growing dwarf palm of the southeastern United States ^[3]. The oily extract is rich in free fatty acids and their esters together with phytosterols, and different manufacturing methods, such as hexanic, ethanolic, and supercritical carbon dioxide extraction, yield preparations with somewhat different compositions ^[4]. It is sold as a botanical dietary supplement rather than an approved drug ^[1].

The berries were used historically by Native American peoples and later entered Western herbal medicine, and for decades saw palmetto has been one of the most popular phytotherapies for the aging prostate in the United States and Europe ^[3]. Its main promoted use is to relieve the lower urinary tract symptoms of benign prostatic hyperplasia, such as frequent urination, weak stream, nighttime urination, and incomplete bladder emptying, and it is also marketed, with little supporting evidence, for hair loss ^[1].

The clinical evidence is largely disappointing for standardized extracts. A large, well-conducted randomized trial found that saw palmetto was no better than placebo at reducing urinary symptoms, even when the dose was doubled and tripled ^[2]. Cochrane systematic reviews reached the same conclusion, reporting that Serenoa repens alone provides little to no benefit over placebo for urinary symptoms or quality of life, with adverse events comparable to placebo ^[1][3]. Some meta-analyses focused on a specific hexanic extract sold as Permixon have suggested modest improvement in urinary frequency and symptom scores, so the possibility of preparation-specific effects remains debated ^[4].

Proposed mechanisms include inhibition of the enzyme 5-alpha-reductase, which converts testosterone to the more potent androgen dihydrotestosterone, along with anti-inflammatory and anti-androgenic actions on prostate tissue, but these effects are weak and have not translated into reliable clinical benefit ^[1][4].

Saw palmetto is available as softgel capsules, tablets, dried berries, liquid extracts, and teas, often standardized to a defined fatty acid content ^[1]. It is generally well tolerated, with mild gastrointestinal upset and headache the most common complaints ^[1][2]. Notably, it can lower prostate-specific antigen (PSA) readings, which may complicate screening for prostate cancer, and it may add to the bleeding risk of anticoagulant and antiplatelet medicines ^[1].

It's generally well tolerated, with occasional mild stomach upset, headache, or dizziness. Because it affects androgen pathways, it could theoretically interact with hormonal treatments, and it may have mild blood-thinning effects worth noting before surgery. It's not for pregnant people because of the hormonal activity.