Testosterone therapy can help reverse the effects of hypogonadism, but it’s unclear whether testosterone therapy would have any benefit for older men who are otherwise healthy. Although some men believe that taking testosterone medications may help them feel younger and more vigorous as they age, few rigorous studies have examined testosterone therapy in men who have healthy testosterone levels — and some small studies have revealed mixed results. For example, in one study healthy men who took testosterone medications increased muscle mass but didn’t gain strength.