Testosterone is a hormone produced by the testicles and is responsible for the proper development of male sexual characteristics. Testosterone is also important for maintaining muscle bulk, adequate levels of red blood cells, bone growth, sense of well-being and sexual function.
Inadequate production of testosterone is not a common cause of erectile dysfunction; however, when ED does occur due to decreased testosterone production, testosterone replacement therapy may improve the problem.
II. What causes testosterone
As a man ages, the amount of testosterone in his body gradually declines. This natural decline starts after age 30 and continues throughout life. Other causes of lowered testosterone levels include:
Edited by Tracy Shuman, MD, November 2005, WebMD.
Copyright © 2004, The Cleveland Clinic.