NYT Syndicate

You're facing 40 and wondering what changes lie ahead. One that's likely, according to clinical studies, is a drop in testosterone. In a process some doctors term "andropause," testosterone levels in the body often decrease by one percent a year after age 40, and by age 70, many men produce only a third of what they once pumped out.

Such news is bound to interest those who want to live a long life at full tilt; some scientists now believe that inadequate levels of the hormone can quicken traditional symptoms of aging, such as declining muscle mass, hair loss, and diminished sex drive.

According to 1999 studies by Pennsylvania State University researchers, men with higher levels of testosterone may be less vulnerable to high blood pressure, heart attacks, frequent colds, obesity and depression.

Other studies suggest that testosterone replacement therapy, much like estrogen replacement in women, may boost bone health, making men less vulnerable to bone-weakening osteoporosis, which affects two million American men.

So why aren't men lined up outside drugstores waiting to fill testosterone prescriptions? For one thing, the treatment is definitely not for everyone, and could even be harmful to some men. Many doctors aren't comfortable with testosterone replacement except in the most extreme cases. Also, many men don't even know about replacement therapy - or the symptoms of deficiency.

Of the one million men in the United States with inadequate levels of testosterone, only about 100,000 to 150,000 are receiving treatment, according to the ALZA Corporation, producer of testosterone supplement patches. But whether those one million need therapy is unclear, says Dr. Irwin Goldstein, professor of urology at the Boston University School of Medicine. "There are a lot of different normals, not a single value. Evaluation has to be done on an individual basis."

Traditionally, testosterone replacement therapy has been prescribed only for men whose bodies don't make enough of the hormone on their own; for example, those whose pituitary gland - the body's testosterone regulator - has been destroyed by infection or tumors, or whose testes have been damaged.

Such men may find that naturally occurring problems associated with aging are exacerbated and begin at a much younger age. Osteoporosis, trouble with sex drive and erections, loss of body hair and muscle mass, breast enlargement, depression, infertility and small testes are the main symptoms. Testosterone replacement helps prevent at least some of these, increasing muscle mass and bone strength, a sense of well-being and sex drive.

"We also know that testosterone levels rise before competition," says Dr. Alan Booth, professor of sociology and human development at Penn State and chief investigator of last year's study. "That helps competitors in terms of visual acuity and sensitivity to demands. It helps stamina and makes men more willing to take risks. They feel they can win."

So how do aging men who experience some of these symptoms know if they need testosterone therapy? Experts agree that for now, men need only be aware of the warning signs of low testosterone and to head to a doctor if they occur.

"If a man suffers physically, say, from impotence, and the doctor does appropriate blood tests, and the results are abnormal, and other hormone tests, such as a test of the pituitary, support that, then they should consider therapy," says Goldstein. "But not for a vague use like a desire for a better athletic performance, or for increased sexual drive."

For those who have a real problem, a physician may suggest testosterone injections every two weeks, or the more recently developed testosterone skin patches that patients wear all day.

Patches cost about $100 for a one-month supply and account for about 50 percent of all treatments. A cream form is also being tested. Although pills exist, many doctors, and the FDA, warn that they can cause liver problems.

This increased variety of treatments points to growing awareness of the problem of insufficient testosterone. There's no denying that more men are beginning to think about replacement. But the science of hormones isn't as advanced or complete for men as it is for women, and it is dangerous to think of the new developments as a quick, complete fix.

As Dr. Stephen J. Winters, an endocrinologist at the University of Louisville, points out, men face a much different problem than women. "In women the [hormonal] change is very abrupt around age 50. Within one year after menopause, they are making only 10 percent as much estrogen as they once were. They have hot flashes, irritability, sleeplessness. But in men, testosterone loss happens much more slowly and to nowhere near the same extent. It's not really male menopause."

Also, men who raise their testosterone levels through steroids, for instance, can experience a number of consequences, from depression to "risky, anti-social behavior," says Booth.

A study of more than 4,000 middle-aged men found that those with above-average levels of the hormone were more likely to report injuries, to drink five or more drinks a day, and to smoke. Nor do researchers yet know the impact of testosterone replacement therapy on prostate disease or prostate cancer.

Given those unanswered questions, the treatment remains off the radar screen for most men and many doctors. Only time and research will tell whether testosterone replacement will become more widely accepted. "There are just no rules about testosterone replacement therapy yet," says Winters. "It's an evolving concept, and research is still being conducted."

Vital Signs

Testosterone levels normally decrease by 20 percent between morning and evening. However, one-fifth of men between the ages of 60 and 80 have lower-than-normal testosterone levels. Only 7 percent of men know that hormone replacement therapy is an option.

Copyright 2000 The New York Times Syndicate. All rights reserved.