In a preliminary study conducted by the National Institute of Health (NIH) of testosterone therapy in older men found that restoring levels to those of healthy young men improved sexual function and to a smaller extent effected their ability to walk and the sense of vitality.
This study included 790 men age 65 and older with serum testosterone levels consistently well below the average for young healthy men. They were randomized to receive testosterone gel applied to the skin or a placebo gel daily. Serum testosterone concentration was measured at one, two, three, six, nine and 12 months. The men were also closely monitored for prostate and cardiovascular problems.