Abstract
Androgen deficiency in the aging male is a common condition affecting millions of middle-aged and elderly men. The diagnosis is made with a high index of suspicion based on symptoms, use of an easily completed questionnaire, a physical examination, and laboratory test results showing a decrease in serum testosterone levels. Treatment can be easily accomplished with injections, patches, or gels that allow transcutaneous administration of testosterone. This article will discuss the pathophysiology of androgen deficiency in aging men, the contraindications for using hormone replacement therapy, and suggestions for monitoring patients on hormone replacement therapy.