It should bother you that the nutritional supplement industry is unregulated because there is no way to tell what a supplement contains. Several different studies have shown that at least one third of nutritional supplements do not supply what is on the label. An analysis of supplements promoted for prostate health in Canada came to a similar conclusion.
The authors studied products that were advertised to help a man’s prostate. Most supplements that are advertised to increase prostate health list vitamins and other herbals that do not offer any benefit to the prostate. For example, there is little evidence that any vitamin treats prostate infections, impotence, prostate cancer, an enlarged prostate or any other prostate malfunction. Even if it was effective, the vitamin E content in the supplements tested varied from -41 percent to +57 percent. Different lots of the same brands of supplement also varied considerably in almost half the samples tested.
Lycopene has been shown to help prevent prostate cancer in rats and is associated with reduced incidence of prostate cancer in humans. Lycopene is dirt cheap, but its content varied from -38 percent and +143 percent of the listed amount. Saw palmetto does block the conversion of testosterone to dihydrotestosterone and, therefore, could help prevent prostate enlargement. So saw palmetto could help. Why then do the supplements containing saw palmetto vary from -97 percent to +140 percent of what they claim on the label? This means you could be buying a worthless product with only three percent of what the label claims, which is too little saw palmetto to have any effect.
Journal of Urology, July 2002