Testosterone is the male sex hormone. It is responsible for the physical characteristics that differentiate men and women. For example, men have more body hair, grow beards, and have larger and stronger muscles, a penis and testicles. Testosterone typically begins to decline slightly after the age of 30, but sometimes the hormone production drops at an even younger age. The normal range for testosterone in healthy men is about 300 nanograms per deciliter (ng/dL), while the upper limit is about 800 ng/dL, according to WebMD.
Andropause is the male corollary to female menopause, but it is different in many ways. In women, hormonal production of estrogen drops within a fairly short period. In men, testosterone gradually declines over many years. By the time a man has reached 60, his testosterone production may be as much as 30 percent less than it was at age 30.
It's important to recognize that some of the symptoms of low testosterone may have other causes, such as heart disease or diabetes; men who have these symptoms should be evaluated by a health care professional. Changes in sexual function often occur, such as decreased desire and fewer erections. Low testosterone can cause sleep disturbances. Physical symptoms include increased body fat, decreased muscle bulk and strength, and decreased bone density. Some men experience hot flashes or lower energy levels. Mood changes like depression or difficulty concentrating and remembering things may also occur.
Many men with andropause don't require treatment, but if the symptoms are severe or disturbing, testosterone replacement is available. Testosterone is available as a skin gel, injection, long-acting pellets (placed under the skin), patches and pills (which are currently not approved for use in the US). The majority of men use testosterone gel, according to the Urology Care Foundation, and about 17 percent use injections. One advantage of the gel is that it can be used at home, while an injection requires a visit to a doctor's office.
Click here for additional information about low testosterone.