PURPOSE OF REVIEW: Testosterone replacement therapy for men with organic hypogonadism due to medical disease of the hypothalamic-pituitary-testicular (HPT) axis is uncontroversial. In these men, testosterone replacement replaces the deficient hormone and relieves the signs and symptoms of androgen deficiency. In contrast, the role of testosterone treatment in middle-aged or older men who have clinical features consistent with androgen deficiency accompanied by reductions in serum …