Testosterone is required not only for virilization and normal sexual function, but also for stimulating and maintaining normal bone and muscle mass in men. The past decade has seen a number of important advances in androgen replacement with the addition of transdermal patch and gel formulations to the long-available intramuscular testosterone esters. The advent of more patient-friendly preparations has, in turn, contributed to an expansion of the clinical indications for testosterone therapy to include not only overt hypogonadism but also wasting disorders and aging. However, the potential benefit of testosterone in the aging male is still controversial and awaits the results of large, randomized, placebo-controlled trials. All patients receiving testosterone therapy require measurement of serum testosterone levels to titrate the optimal dose, in addition to monitoring of hematocrit, liver function tests, a lipid profile, and prostate-specific antigen.
Department of Medicine, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts, USA.
Correspondence to Frances J. Hayes, MD, Reproductive Endocrine Unit, BHX5, Massachusetts General Hospital, Boston, MA 02114, USA; e-mail: Hayes.Frances@MGH.Harvard.edu