Getting old is terrifying. That's probably why many men — concerned about gaining weight, losing their sex drives, and generally being schlubbier than they once were — are now turning to testosterone treatments.

Whether testosterone actually slows down the aging process, however, is unclear. Just ask Dr. Sergei Romashkan from the National Institute on Aging.

The problem is that we don't have any evidence that prescribing testosterone to older men with relatively low testosterone levels does any good.

Not exactly a winning endorsement.

And yet, some seniors swear by the stuff, which is available in gel, patch, and shot form. Prescriptions for testosterone have gone up almost 90 percent over the past five years.

Side effects of testosterone use include heart problems and prostate cancer — and those are just the two we know about. As for the benefits, well...

Evidence of the benefits of testosterone is mixed, and the potential health risks are serious. The largest study conducted to date, a 2008 trial involving 230 patients in the Netherlands, found no improvement in muscle strength, cognitive thinking, bone density or overall quality of life among men taking testosterone. Muscle mass increased 1.2%, but not enough to improve physical mobility.

On the other hand, it might make you feel a few years younger. Totally worth it, right?

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