Look Out, Viagra: Testosterone Drugs Gain Popularity

New drugs designed in part to save the sex lives of aging men could become the biggest thing since Viagra, reports Bloomberg. The problem is that the testosterone boosters from Eli Lilly and Abbott are becoming so popular that doctors worry men who don't need them for strictly medical reasons will take them and suffer potentially deadly side effects. Since 2006, prescriptions for testosterone replacement treatments—offered in shots, patches, and even underarm gels—have doubled to 5.6 million. Sales are expected to triple to $5 billion by 2017.

The patients include many of the 13.8 million American men who exhibit low levels of testosterone—the male sex hormone that naturally declines after age 30. But while artificially elevating testosterone can boost a man's sex drive, it can also cause blood clots, prostate cancer, liver damage, and be addicting. “Am I making a deal with the devil?" asks one 43-year-old. "A little bit, but I have to think about my quality of life. It's like I'm in my 20s again.” (More testosterone stories.)