Testosterone is an important hormone that has an effect on almost every aspect of a man’s body. It is produced in the testes and in the adrenal glands. It is to males what estrogen is to females. Testosterone assists the male body in building proteins that play key roles in virtually every bodily function, and it is crucial for normal sexual behavior and giving rise to erections. Testosterone also contributes to several metabolic functions including bone formation, cholesterol metabolism, liver function, prostate gland growth and production of blood cells in bone marrow. It also affects mood.
When men get into their early 30s, testosterone levels drop at a rate of one percent a year (10 percent every decade). At the same time, another factor in the body called Sex Binding Hormone Globulin (SHBG), is increasing. SHBG binds (traps) much of the testosterone in the circulation and makes it unavailable to exert its effects in the body’s tissues. What’s left over does the beneficial work and is referred to as ‘bioavailable’ testosterone.
Every man experiences a decline of bioavailable testosterone but some men’s levels dip much lower than others. And when this happens these men can experience a cluster of andropause symptoms.