Benefits of Testosterone Treatment

Male hypogonadism is a clinical syndrome that results from failure to produce physiological concentrations of testosterone, normal concentrations of sperm, or both. Hypogonadism may result from disease or dysfunction of the testes (primary hypogonadism) or hypothalamic–pituitary unit (secondary hypogonadism). In young men with organic (classic) hypogonadism that results from diseases of the hypothalamus, pituitary, or testes, testosterone replacement therapy results in beneficial effects, which include induction and maintenance of secondary sexual characteristics, improvement in sexual function, increase in lean mass and improvement of bone mass and quality. In these young androgen-deficient men, testosterone therapy is generally safe and associated with few adverse effects. In contrast to the organic hypogonadism, the relatively low incidence of which has remained unchanged for decades, symptomatic older men with low circulating serum testosterone concentrations are increasingly being seen in clinical practice and commonly referred to as ‘late-onset’ or ‘age-related’ hypogonadism. This age-related decline in testosterone levels is generally small compared to men with organic hypogonadism. The evidence for clinical benefits of testosterone treatment in older men is limited and long-term risks (mainly prostate and cardiovascular) remain unknown. In this chapter, we will review efficacy of testosterone replacement therapy in men with organic hypogonadism as well as in men with age-related decline in testosterone.