When needed, testosterone replacement therapy (TRT) can boost T levels back to normal and return him to the man he used to be.
"Despite all the recent advertising campaigns, awareness of low T and its importance for men’s health remains very poorly recognized by both the public and by physicians," says Abraham Morgentaler, MD, director of Men's Health Boston and author of Testosterone for Life: Recharge Your Vitality, Sex Drive, Muscle Mass, and Overall Health.
Still, there are also risks to TRT, and the long-term safety isn't clear. Here's what men need to know.
Normal levels of testosterone range from about 300 to 900 nanograms per deciliter (ng/dL), and there's little to suggest that men whose levels fall within that range would benefit from therapy, says urologist Michael Eisenberg, MD, director of male reproductive medicine and surgery at Stanford Hospital and Clinics in Palo Alto, Calif.
However, that range covers a man's total amount of testosterone, which may not be the whole picture.
Experienced doctors, Eisenberg says, will also measure what's called free testosterone, which is the amount of the hormone that is active in the body at a given time. A man with total testosterone in the normal range may still have the classic symptoms of low T if his free testosterone measurements come up short.
"Free testosterone is more indicative of the true testosterone status," Morgentaler says. He discloses consulting or research work for the drug companies Lilly, Auxilium, Slate Pharmaceuticals, and Endo Pharmaceuticals.
Low free testosterone, says Morgentaler, has been almost exclusively linked to sex difficulties, and there's no doubt that TRT can renew a man's interest in sex as well as his ability to maintain an erection. It can also restore the "wow" factor to his orgasms, Morgentaler says.
For many men, treating the sexual symptoms of low T would be enough reason to start therapy. However, low testosterone influences a man's health well beyond the bedroom. Bringing it back up to normal can have a positive impact on a variety of crucial health markers.
Testosterone may also play a role in how long men live. Recent studies, Morgentaler says, show a link between low testosterone and shorter life expectancy.
"Men with low T die sooner than men with normal levels of testosterone," he says.
It's not clear if low testosterone, by itself, makes earlier death more likely. Many other factors could also be involved. It's also not clear if boosting testosterone to normal levels will impact longevity.
The link, though, makes sense to Morgentaler. "On testosterone, we see that fat mass goes down while muscle mass goes up," he says. "We know that that is good for overall health."
Morgentaler also says that treating low T can strengthen a man's bones and help prevent osteoporosis. Some evidence also suggests that treatment can also aid blood sugar control, which is important for the prevention and control of diabetes.
Testosterone is also tied to heart health, says Eisenberg, who discloses that he has received a grant from Endo Pharmaceuticals to study the association between testosterone and health.
"Lower testosterone levels have been linked to higher risk of cardiovascular problems," Eisenberg says. Again, it's not clear if low testosterone levels actually cause heart problems.
Both Eisenberg and Morgentaler say that testosterone therapy can dramatically affect a man's quality of life. Besides its sexual benefits, TRT can improve a man's mood and energy level while reducing irritability and anger.
What Are the Risks?
There are some cautions men should know about.
Men who use a testosterone gel should wash their hands thoroughly after applying a dose and make sure that no one else touches the spots where they medicate. If a woman or child comes into contact with testosterone gels, it can cause side effects in them, including hair growth and premature puberty.
"Although all testosterone creams or gels have the potential to be transferred to women or children, in practice this is exceedingly rare. I've never seen a case," Morgentaler says.
Still, as a precaution, he advises men to avoid skin-to-skin contact with women, children, or pets for the first two to four hours after applying medication. A nasal gel is now available that eliminates the risk of exposure to others.
To continue to benefit, a man with low testosterone must remain on it. However, says Eisenberg, we don’t know a lot about its long-term safety.
Finally, there's the question of prostate cancer risk. Research over the past few decades has shown little evidence of a link between testosterone replacement therapy and prostate cancer. However, the question has not been entirely laid to rest. Eisenberg recommends that his testosterone replacement therapy patients get a PSA test once or twice a year to check for possible signs of concern.
For Morgentaler, the benefits far outweigh the risks for men who are otherwise healthy yet have low testosterone levels, and he says the results of treatment are rewarding for him as well as for his patients.
"This is one of the very few areas of medicine where a male patient will come to you and say, 'You made me feel like myself again,'" Morgentaler says. "I hear from their wives, too, who say, 'You gave me my husband back.'"