Testosterone therapy for transgender men.

Testosterone therapy is a cornerstone of medical treatment for transgender men who choose to undergo it. The goal of testosterone therapy is usually to achieve serum testosterone concentrations in the male reference range. Testosterone has several desired effects as well as undesired and unknown effects. The desired effects include increased facial and body hair, increased lean mass and strength, decreased fat mass, deepening of the voice, increased sexual desire, cessation of menstruation, clitoral enlargement, and reductions in gender dysphoria, perceived stress, anxiety, and depression. Achievement of these goals comes with potential undesired effects and risks including acne, alopecia, reduced HDL cholesterol, increased triglycerides, and a possible increase in systolic blood pressure. An additional benefit of testosterone therapy (with or without mastectomy) is a reduced risk of breast cancer. Most of the effects of testosterone start to develop within several months of starting therapy, although facial hair and alopecia continue to develop after 1 year. A major limitation in the study of testosterone therapy for transgender men is a paucity of high-quality data due to a shortage of randomised controlled trials (partly because of ethical issues), few prospective and long-term studies, the use of suboptimum control groups, loss to follow-up, and difficulties in recruitment of representative samples of transgender populations.