Androgens play a crucial role in bone, muscle and fat metabolism, erythropoiesis and cognitive health. In men aged 40-79 years the incidence of biochemical deficiency and symptomatic hypogonadism is 2.1-5.7%. Decreased libido or reduced frequency and quality of erections, fatigue, irritability, infertility or a diminished feeling of wellbeing may be presenting complaints. However, a significant proportion of men with androgen deficiency will be identified when they present for unrelated concerns.