Testosterone Deficiency and Replacement in Older Men

It is now clear that men have gradual declines in average serum testosterone levels as they age. These decreases begin by middle age and continue into old age.1,2 Although the decreases are substantial in many men, they are quite variable. Some men, even in old age, maintain serum testosterone levels similar to those of healthy young men.Many of the physical and behavioral changes that occur in men as they age are similar to those that occur in younger men with hypogonadism. These changes include decreases in muscle mass, strength, bone mass, and sexual function and increases in body . . .