Androgen effects on body composition and muscle function: implications forthe use of androgens as anabolic agents in sarcopenic states

Testosterone-induced nitrogen retention in castrated male animals, eunuchoi dal men, pre pubertal boys and women, and the sex-related differences in th e size of the muscles between male and female animals, have been cited as e vidence that testosterone has anabolic effects. Recent studies have reporte d that replacement doses of testosterone in hypogonadal men and supraphysio logical doses in eugonadal men increase fat-free mass, muscle size and stre ngth. These effects have provided the rationale for exploring these anaboli c applications in sarcopenic states. Although emerging data demonstrate mod est gains in fat-free mass in HIV-infected men given replacement doses of t estosterone, we do not know whether testosterone supplementation can produc e clinically meaningful changes in muscle function and disease outcome in p atients with wasting disorders.