Some men between the ages 45 and 60 years develop complaints and symptoms reminiscent of menopausal complaints in women. So, parallels were sought between the changes in female and male endocrinology during that period of life. Indeed, men do show a decline of serum testosterone from age 40 to 50 years onwards but it is a slow decline of 1-2% per year and over time it may amount to hypogonadism. The mechanism of a decline in serum testosterone in men does not resemble the menopause; it is partially an aging neuroendocrine system with a less efficient testosterone production but equally or more important, the result of inhibition of testosterone production by metabolic factors in relation to visceral obesity. These effects are in part reversible with weight loss. A hypogonadal state in aging men has deleterious effects. Mortality of all causes is highest in men with low testosterone impacting on their metabolic state leading to diabetes mellitus, cardiovascular disease, osteoporosis, and sexual dysfunction. Normalization of testosterone in aging hypogonadal men has a beneficial effect on the above pathologies. The fear that testosterone treatment of elderly men would lead to prostate disease has not been substantiated in studies. So, while men do not have a 'menopause', testosterone deficiency in old age deserves serious attention. (C) 2014 Elsevier Ireland Ltd. All rights reserved.