Saw palmetto has been used for centuries to manage prostate and urinary tract problems, and that tradition continues today. For men who have BPH, the presence of beta-sitosterol in saw palmetto appears to be a reason the herb can be helpful in managing this prostate condition.
Saw palmetto extract lowers levels of dihydrotestosterone (DHT), which is associated with BPH, by blocking the activity of 5-alpha-reductase (an activity attributed to beta-sitosterol) and receptor sites on cell membranes that the cells need to absorb DHT.
Among men with prostatitis, saw palmetto may offer relief as well. In a study of 106 men who had chronic bacterial prostatitis, saw palmetto was one of four ingredients (along with quercetin, turmeric, and stinging nettle) in a formula used in the trial. The men took the natural supplement formula along with an antibiotic for one month, while another group of 37 men took the antibiotic alone. At the end of one month, 89.6 percent of men who received the herbal supplement had no symptoms of prostatitis compared with 27 percent of the men who took the antibiotic only. (Cai 2009)
The impact of saw palmetto extract on prostate cancer cells may also hold promise. Italian researchers found that prostate cancer cells treated with saw palmetto extract underwent cell death within 24 hours. (Baron 2009) A typical dose of saw palmetto is 320 mg daily of extract standardized to contain 85 to 95 percent sterols and fatty acids, which are the main compounds of the herb. Possible side effects include back pain, erectile difficulties, and headache.
Baron A et al. Sereona repens extract targets mitochondria and activates the intrinsic apoptotic pathway in human prostate cancer cells. BJU Int 2009 May; 103(9): 1275-83
Cai T et al. Serenoa repens associated with Urtica dioica (ProstaMEV) and curcumin and quercetin (FlogMEV) extracts are able to improve the efficacy of prulifloxacin in bacterial prostatitis patients: results from a prospective randomized study. Int J Antimicrob Agents 2009 Jun; 33(6): 549-53