Evidence Level
Saw palmetto is an herbal supplement commonly studied for its effects on men's health and hair loss. A 2012 Cochrane review by Tacklind et al. analyzed 32 randomized controlled trials involving 5,666 men with benign prostatic hyperplasia (BPH), concluding that Serenoa repens was well-tolerated but only produced mild improvements in urinary symptoms compared to placebo. However, some individual studies reported more significant benefits.
Barry et al. (2011) conducted a large NIH-funded trial (CAMUS study) published in JAMA, which found that saw palmetto at doses up to 960mg did not significantly improve lower urinary tract symptoms (LUTS) compared to placebo. This study was criticized for using an ethanolic extract instead of the standard liposterolic form.
Conversely, Ye et al. (2019) published a meta-analysis in Medicine showing that Permixon, a specific liposterolic saw palmetto extract, significantly improved International Prostate Symptom Score (IPSS) scores and was comparable to tamsulosin for managing symptoms of BPH. The conflicting results likely stem from differences in extract quality, standardization, and study populations.
In terms of safety, Agbabiaka et al. (2009) conducted a systematic review of 40 studies involving 24 manufacturers/distributors and found that Serenoa repens monopreparations are generally well-tolerated, with mild adverse events such as abdominal pain and nausea reported, but no serious drug interactions noted.
Overall, saw palmetto's efficacy and safety profile suggest it may offer mild benefits for urinary symptoms and hair health, but further research is needed to clarify its role in these areas.