Testosterone’s role in bad behavior is largely a myth. What’s more, testosterone plays other important roles in health and disease that may surprise you. For example, did you know that testosterone is a key player in prostate cancer? Or, that women need testosterone, too? There’s more to testosterone than guys behaving badly.
Testosterone is the major sex hormone in males and plays a number of important roles, such as:
Having too much naturally-occurring testosterone is not a common problem among men. That may surprise you given what people might consider obvious evidence of testosterone excess: road rage, fighting among fathers at Little League games and sexual promiscuity.
Part of this may be due to the difficulty defining “normal” testosterone levels and “normal” behavior. Blood levels of testosterone vary dramatically over time and even during the course of a day. In addition, what may seem like a symptom of testosterone excess (see below) may actually be unrelated to this hormone.
In fact, most of what we know about abnormally high testosterone levels in men comes from athletes who use anabolic steroids, testosterone or related hormones to increase muscle mass and athletic performance.
Problems associated with abnormally high testosterone levels in men include:
In recent years, researchers (and pharmaceutical companies) have focused on the effects of testosterone deficiency, especially among men. In fact, as men age, testosterone levels drop very gradually, about 1% to 2% each year — unlike the relatively rapid drop in estrogen that causes menopause. The testes produces less testosterone, there are fewer signals from the pituitary telling the testes to make testosterone, and a protein (called sex hormone binding globulin (SHBG) increases with age. All of this reduces the active (free) form of testosterone in the body. More than a third of men over age 45 may have reduced levels of testosterone than might be considered normal (though, as mentioned, defining optimal levels of testosterone is tricky and somewhat controversial).
Symptoms of testosterone deficiency in adult men include:
Did You Know?
|There are times when low testosterone is not such a bad thing. The most common example is probably prostate cancer. Testosterone may stimulate the prostate gland and prostate cancer to grow. That’s why medications that lower testosterone levels (for example, leuprolide) and castration are common treatments for men with prostate cancer. Men taking testosterone replacement must be carefully monitored for prostate cancer. Although testosterone may make prostate cancer grow, it is not clear that testosterone treatment actually causes cancer.
Diseases and Conditions That Affect Testosterone
Men can experience a drop in testosterone due to conditions or diseases affecting the: