ABSTRACT
Male hypogonadism is a common clinical condition that causes testosterone (T) deficiency and affects the health and well-being of males of all ages. For example, androgen deficiency is a major manifestation of the Klinefelter syndrome, a chromosomal disorder that is characterized classically by an XXY karyotype and affects about one in 500 males (1,2). Furthermore, low serum T levels occur commonly in a broad spectrum of common clinical conditions such as in men with chronic medical illnesses (e.g., chronic renal failure, lung disease, and liver failure), wasting syndromes (e.g., HIV infection and cancer), the use of certain medications (e.g., glucocorticoids and central nervous system-acting drugs such as opiates), and normal aging (commonly referred to as “andropause”) (3). These conditions are also associated with clinical manifestations that are consistent with androgen deficiency such as decreased muscle mass and strength, low bone mineral density (BMD), sexual dysfunction, and reduced energy, well-being, and mood.
