Put at its simplest, Andropause is caused by too little free testosterone and too much estrogen.  Of course life is never simple, and it should be recognized that testosterone is much more than a sex hormone. With receptor cites in several organs and throughout the body, testosterone is critical in maintaining healthy bone density, lean muscle, and red blood cell production.  Furthermore testosterone is vital for proper cardiac output and neurological function.

Why testosterone levels are low can be that the male simply has low testosterone production, resulting in switching off some of the normal activity of the testes. Starting at about age 30, testosterone levels drop by approximately 10 percent every decade, and as men age, their testosterone is increasingly converted to estrogen.

At the same time, another factor in the body called Sex Binding Hormone Globulin, or SHBG, is increasing. SHBG is a protein that binds to the testosterone, and traps a lot of the testosterone that is still circulating and stops it from exerting its effects in the body. What's left over does the beneficial work and is known as "available" testosterone.

Andropause is associated with low (available) testosterone levels. Every man experiences a decline of available testosterone with age, but some men's levels dip lower than others. It is when available testosterone levels dip low that these men can experience andropausal symptoms.

These symptoms can impact their quality of life and may expose them to other, longer-term risks of low-testosterone. Some estimates suggest that 30 percent of men in their 50s will have testosterone levels low enough to be causing symptoms or putting them at risk.

The importance of testosterone >>