This article has no abstract; the first 100 words appear below.

Aging is variably but inevitably accompanied by declines in health; concomitantly, in men, circulating sex-steroid levels fall with age.1 To what extent these two processes are causally linked and whether testosterone therapy can prevent or ameliorate important age-related problems have been major issues in men’s health. In 2003, a committee assembled by the Institute of Medicine (IOM) found a paucity of randomized, placebo-controlled clinical trials involving older men and noted a lack of definite evidence that testosterone therapy conferred benefits.2 The committee recommended that clinical trials be initiated, first to evaluate the efficacy of testosterone supplementation in older men and . . .