[Therapy of male hypogonadism]

One of the most frequent, but also most undiagnosed, endocrinopathies is male hypogonadism (testosterone deficiency). Understanding the variety of clinical pictures male hypogonadism exhibits is pivotal for diagnosis and putative treatment. There can be disturbances of mood and cognitive abilities as well as sexual functions. Further on, a decrease in muscle mass and strength, an accumulation of body fat and osteopenia/osteoporosis as well as anemia might be observed. There are indications that insulin sensitivity is mitigated in a state of androgen depletion, especially due to an inverse association of testosterone to the metabolic syndrome. In older men, symptoms of androgen deficiency may feature a differential profile due to accompanying co-morbidities. Restoring serum testosterone levels by substitution therapy can markedly attenuate, if not relieve, the clinical picture of hypogonadism. New treatment modalities have been introduced, including short-acting transdermal as well as long-acting depot preparations. Herewith, the diagnostic pathways to describe or exclude male hypogonadism and as well as various options of initiation and surveillance of testosterone substitution therapy are elucidated. Future perspectives of andrology regarding metabolic and pharmacogenetic aspects are discussed.