Produced primarily by the testicles, testosterone is the hormone responsible for developing male sexual traits and maintaining muscle mass, bone density and red blood cell levels. Testosterone levels peak in adolescence and early adulthood then begin to decline with age, typically at a rate of 1 to 2 percent per year after age 30. Testosterone levels influence physical, emotional and sexual well being, with higher testosterone generally having a favorable effect on attitude and performance. Though increasing testosterone can have benefits, changes to testosterone levels can affect hormonal production elsewhere in the endocrine system, so consult a doctor prior to attempting to raise your testosterone.
Testosterone levels generally peak during adolescence and early adulthood. As you get older, your testosterone level gradually declines — typically about 1 percent a year after age 30 or 40. It is important to determine in older men if a low testosterone level is simply due to the decline of normal aging or if it is due to a disease (hypogonadism).