Sexual male enhancement, as the euphemism goes, is big business. Last year, Viagra, the pharmaceutical market leader, raked in about $2 billion. That success has spawned a shadow industry of largely unregulated "natural male enhancement," or sex pill, products. But according to the FDA, some of these products aren't natural, aren't tested and some might even be dangerous. Here's a list of 10 sex pill products the FDA issued health warnings about this year or told manufacturers to get them off the shelves.

It's not clear if "Stiff Nights" is a "dietary supplement" as its maker claims, or a bad b-movie title, but in either case the FDA says men looking to "regain the thunder" should stay clear because the pill really contains sulfoaildenafil, an untested chemical similar to the active ingredient in Viagra, which can interact badly with nitrates and cause low blood pressure. FDA Warning. Male Pills To Last Longer

Dangerous male sex pills that can hurt more than help erectile dysfunction

The marketing geniuses behind "Stiff Nights" also sell "Rock Hard Weekend." Same unregulated chemical, says the FDA, different laugh out loud brand. FDA Warning.

It's not clear who Don Wands is or how he became so magical, but the FDA didn't seem to care. In August 2010, they told the manufacturer of this supplement to drop the magic act and take it off the shelves because the product's two main ingredients, hydroxyhomosildenafil and sulfoaildenafil, aren't listed on the box, aren't "supplements" and aren't really tested. FDA Warning.

If you wind up with Duro Extend in your stocking this year, you might want to send it back to Santa. The FDA recalled the product in early December 2010 because the "dietary supplement" is secretly supplemented with sulfoaidenafil, a drug similar to Viagra, but not tested. FDA Warning.

Eager men trying to get their hands on a box of Xiadafil VIP, might have to wait in line. In July 2010, U.S. Marshals seized almost $75,000 worth of it after the manufacturer refused an FDA request to recall it. The problem? The FDA says the product's VIP power comes from hydroxyhomosildenafil, a drug similar to Viagra, but untested. FDA Warning.

First published on December 22, 2010 / 11:50 AM