Male hormone use soars despite unknown risks.(CR health)

Surging sales of the male hormone testosterone, available by prescription in patches, tablets, gel, or injection form, have outpaced the scientific evidence about whether testosterone therapy helps or harms older men who have borderline or normal testosterone levels. That warning came in a November report from the Institute of Medicine, part of the National Academy of Sciences.

An estimated 2 million mostly middle-aged and older American men use the hormone, increasingly to treat weakness, depression, impotence, or waning sex drive. That's roughly four times the number of men who used testosterone just five years ago.

"There is still much we don't know about how decreased testosterone levels affect men's health and whether testosterone therapy might increase the risk of prostate cancer," says Dan Blazer, M.D., Ph.D., chairman of the Institute of Medicine panel.

Testosterone levels slowly decline as men age. By their 60s, roughly one-fifth of men have testosterone levels that would be on the low end of normal for younger men; by their 70s, one-third do. Those modest declines have been linked with problems such as weak muscles, brittle bones, decreased sex drive, impotence, depression, and, possibly, poor cognitive function. But it's unclear whether those associated problems are caused by the hormone decline and whether supplemental ...