San Francisco Group Performs 1-Year Clinical Trial
February 10, 2006 - Medical investigators have subjected the saw palmetto herb to a rigorous test, and the herb was found to be no more effective than placebo in relieving symptoms and improving flow in older men with prostate trouble.
The one-year trial, funded by branches of the National Institutes of Health, is unique. Compared to prior studies, this one used a pure, standardized product, and it was carefully double-blinded, adequately powered, and employed standard measures of efficacy (symptoms, uroflow, PSA, prostate volume). The authors conclude: "In this study, saw palmetto did not improve symptoms or objective measures of benign prostatic hyperplasia."
The study results will come as a disappointment to the two million American men believed to be using saw palmetto products to self-medicate for 'prostate trouble.' Furthermore, the trial may have little impact on men who prefer an alternative-medicine approach to treatment.
In fact, the American Botanical Council (ABC), a leading nonprofit organization dedicated to the responsible use of herbal products, has issued a press release stating, "Our primary concern with this trial is the relatively advanced condition of the prostate problems in many of the men who were tested.." Full text of the ABC press release is available here.
Authors of the study point out a fundamental quandary with any herbal product:
"The level of active ingredient in the extract (saw palmetto, in this case) may not have been sufficient to produce a measurable effect. We cannot completely address this possibility, because the active ingredient in saw palmetto, if one exists, is not known."
In an accompanying editorial, DiPaola and Morton state that a limitation of the study is that one specific preparation of saw palmetto was tested, leaving open the possibility that another product may have yielded different results.
A widely-acclaimed USRF study in 2001 showed that one saw palmetto product may function as a mild inhibitor of the enzyme 5-alpha reductase, partially depriving the prostate of its major androgenic nutrient dihydrotestosterone (DHT). This mechanism of action, also demonstrated in a controlled trial, may not be powerful enough to induce symptomatic or flow improvement.