"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.
"Today, we recognize, based on dozens of studies, its importance relative to health issues such as diabetes, obesity, metabolic syndrome, and osteoporosis," Morgentaler says.
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.