Men’s testosterone levels are believed to decline as a natural part of aging. Some prescription drugs as well as environmental and lifestyle factors might also play a role. But doctors are prescribing testosterone drugs at record levels. Between 2001 and 2011, hormone use by men over age 40 nearly quadrupled. There could be significant risks. Several recent studies show a higher rate of heart attack and stroke in older men taking testosterone. Many doctors say that for men with truly low testosterone, the benefits of hormone therapy outweigh the risks. A discussion on the safety of prescription testosterone.