Testosterone: The good and the bad
December 3, 1999
Web posted at: 3:19 PM EST (2019 GMT)
By Lynda Liu
When you think of testosterone, you probably think of the rough and rugged. It's one of the things that make men men. But even this most masculine of hormones requires a delicate balance.
Produced by the testes (though women's ovaries make some, too), the hormone propels prepubescent boys toward deeper voices and hairy chests. In a grown man, it fuels a healthy libido, builds muscle mass and helps maintain his energy levels. But too much of it -- or too little -- can wreak havoc on a man's behavior and physique.
Why more isn't always better
According to a study in the April 1999 Journal of Behavioral Medicine, higher-than-average testosterone levels offer certain benefits but also carry some serious risks. Researchers at Pennsylvania State University in University Park, Pennsylvania, reviewed the records of 4,393 men between the ages of 32 and 44 who had served in the military between 1965 and 1971. Their blood had been drawn to determine testosterone levels -- which ranged from 53 to 1,500 nanograms per deciliter, with an average of 679. (The normal range in males is 270 to 1,070 nanograms.)
Men whose testosterone levels were slightly above average were 45 percent less likely to have high blood pressure, 72 percent less likely to have experienced a heart attack and 75 percent less like to be obese than men whose levels were slightly below average. These men were also 45 percent less likely to rate their own health as fair or poor.
But the results weren't all rosy. These men were also 24 percent more likely to report one or more injuries, 32 percent more likely to consume five or more drinks in a day, 35 percent more likely to have had a sexually transmitted infection, and 151 percent more likely to smoke.
The news got worse at very high testosterone levels (1000 nanograms), where men were even more likely to engage in risky behavior -- and less likely to reap the positive health benefits of testosterone.
The results aren't really surprising, says lead author Alan Booth, Ph.D., a professor of sociology and human development, because testosterone has been associated with risky behavior in many studies. Men with high testosterone levels are more likely to be involved in criminal activity and antisocial behavior, get in trouble in school, remain single and be unemployed.
But this doesn't mean that all men with high testosterone levels are doomed to a bad fate, he said. "There's lots of high testosterone people out there with good marriages who don't commit crimes."
Taking all the factors together, researchers found that the healthiest men overall had testosterone levels between 400 to 600 nanograms. They seemed to enjoy the most benefits and experience the least risks associated with the hormone.
When medical treatment is needed
Some men may have higher testosterone levels than others, but it's rare that a man's level is so high that he needs treatment, says Eugene R. Shippen, M.D., author of "The Testosterone Syndrome." It's much more common, he says, to treat low testosterone levels.
A man's testosterone level peaks at age 20 and then slowly declines for the rest of his life. A problematic decrease can happen to men as early as their 30s, says Shippen. "It's rare in the 30s, infrequent in the 40s, relatively common in the 50s and pretty common in the ages above."
Medically, the condition is known as hypogonadism -- the underproduction of testosterone in the testes -- but it's commonly referred to as "male menopause." This drop in testosterone is accompanied by a decrease in sex drive and sexual dysfunction; a decline in physical energy, strength and stamina; more aches and pains in the bones and joints; and less initiative and mental aggressiveness. In short, says Shippen, the aging process accelerates.
Doctors can treat low testosterone levels with injections, patches and topical creams or gels. A man on hormone replacement therapy will use it for the rest of his life, in the same way that women taking estrogen do.
Know your testosterone
Once a man is on replacement therapy, it's important to monitor his testosterone levels, says Booth. A man may feel better at first, but if his levels get too high he could become aggressive and angry.
In fact, monitoring testosterone levels every five years is a good idea for all men 35 or older, says Shippen. "The reason to do testing in younger men periodically is to establish baseline levels when they're healthy." Doctors can then compare levels as men get older and make sure no significant drops take place.
Copyright 1999 WebMD, Inc. All rights reserved.
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