Purpose of review: As testosterone levels are frequently reduced in obesity, an understanding of the relationship between serum testosterone and adiposity is necessary in the clinical evaluation of these men, in particular when considering testosterone therapy.
Recent findings: Population and interventional data suggest a bi-directional relationship exists between testosterone and obesity in men, with lower total testosterone and sex hormone binding globulin (SHBG) (and to a lesser extent free testosterone) levels than their nonobese peers; obesity having an impact at least as important as ageing. Abnormalities in the hypothalamo-pituitary-testicular axis are seen with increasing obesity. Weight loss in massive obesity increases testosterone levels but its role in mild-moderate obesity is unclear. Testosterone supplementation reduces total body fat in hypogonadal and ageing men although the effects on regional fat distribution are less well described.
Summary: Favourable changes in total body fat and regional fat distribution suggest a potential role for testosterone in obesity. However, lifestyle advice to achieve sustained weight loss should be the mainstay of management. Obese men with confirmed androgen deficiency can be offered treatment, whereas in those with low-normal testosterone levels more research is needed.