Anyone watching television late in the evening has seen the ads for "natural male enhancement" products -- dietary supplements whose manufacturers imply that users will have increased libido and unimpaired sexual performance. Because these products are dietary supplements, rather than drugs, they are regulated in a different way by the FDA than pharmaceutical products. Dietary supplements aim to fill nutritional gaps left by improper food intake; their manufacturers are responsible for determining that any claims they make about the products are not misleading. The FDA's role in regulations dietary supplements is chiefly to attempt to ensure their safety, much the way the agency tries to make sure that food processed in the United States is safe for consumption.
Another component of being regulated by the FDA is the requirement that all ingredients be listed on the label of dietary supplements. Ingredients intended to fulfill the "supplement" component of the product are listed in a section entitled "Supplement Facts," and other ingredients meant to provide color, flavor, or other similar features are listed in an "other ingredient" statement on the label. Unfortunately for Midwest Wholesale, a crucial ingredient was not listed on the labels for several of its "natural male enhancement" products, including Boost, Sexy Monkey, and "new" ExtenZe.
According to the manufacturer's voluntary recall statement, several of the company's products distributed between August 2013 and October 2013 contain undeclared sildenafil and / or tadalafil. The names of those compounds are likely familiar to readers of this column as the active ingredients in Viagra and Cialis, respectively. Sildenafil, tadalafil, and vardenafil (the active ingredient in Levitra) are PDE5 inhibitors: drugs that block the degradation of cyclic GMP by phosphodiesterase type 5. It is easy to see why Midwest Wholesale would pull ExtenZe, Triple MiracleZen Platinum, and similar products from stores: although sildenafil and tadalafil are off-patent, companies that wish to manufacture and market generic versions of these drugs must file abbreviated new drug applications (ANDAs) before doing so.
Midwest Wholesale has indicated that the products containing undeclared PDE5 inhibitors were distributed over a short period of time during the late summer and early fall of 2013. Photos of the relevant packaging are available here and here (the FDA's Flickr photostream), and lot numbers are listed here. Individuals seeking natural remedies for impaired sexual performance may wish to consult the article "Exploring scientifically proven herbal aphrodisiacs," published in the January 2013 issue of Pharmacognosy Review. The full text of this article is available free of charge from the National Libraries of Medicine.