Exogenous Androgens and Male Reproduction.

Due in part to aggressive marketing, the prevalence of exogenous androgen use has increased to disturbing levels. Prescribing practitioners are often unaware of the severity of the anti-fertility effects. Exogenous androgens should only be prescribed if hypogonadism has been established by appropriate investigation, and preferably the patient does not intend to father a child. There are alternative medications, or combinations of medications, that can be used if hypogonadism is present and fertility is desired.It is somewhat counterintuitive that testosterone treatment will decrease or abolish fertility. Exogenous testosterone inhibits spermatogenesis by removing the feedback response to low testosterone at the hypothalamus and pituitary. This results in reduced synthesis and secretion of gonadotropins required to stimulate endogenous testosterone production and to support spermatogenesis. It is important to realize that the normal testicular levels of testosterone are approximately 100 times the concentration in circulation. These high levels are required locally to support spermatogenesis. So even with circulating androgen levels within the normal range, spermatogenesis fails due to insufficient gonadotropin and local testosterone support. Androgenic herbal supplements and illicit use of anabolic steroids have contributed to this serious challenge in the treatment of infertile men. Most men will recover normal spermatogenesis after cessation of exogenous testosterone treatment, but this requires 6 months or more in most men. In rare cases fertility is permanently impaired.