Those late-night ads telling aging men that "low T" may be the reason they've lost the spring in their step appear to be reaching their audience. Use of testosterone therapy has increased dramatically over the past decade, according to a new study.
But experts worry that too many men may be taking the supplements without understanding the potential risks.
Researchers at the University of Texas Medical Branch at Galveston pointed out that the development of new drugs, particularly topical gels, also likely played a role in this trend.
The study, published in the current issue of JAMA Internal Medicine, involved more than 10 million men aged 40 years and older. The researchers found use of testosterone therapy was three times higher in 2011 than it was in 2001. Over the course of the decade, testosterone therapy increased from 0.81 percent to 2.91 percent.
The investigators noted that 2.29 percent of men in their 40s and 3.75 percent of men in their 60s were taking some form of testosterone therapy by 2011.
While sales may be booming, the risks involved with supplements of the powerful male hormone remain uncertain. One study presented last month at the annual meeting of the American Urological Association suggests that use of testosterone might be an underappreciated cause of male infertility.
The study, by researchers from the University of Alabama and the University of Kansas, found that sperm production bounced back to healthier levels when some men being treated at fertility clinics stopped using testosterone supplements.
Another study published at the same meeting found that many online vendors of testosterone supplements accentuate supposed benefits from the drug, but minimize the risk.
The study, which looked at 70 websites from companies across the United States, found that just 27 percent of the online vendors described potential side effects, which experts say can include liver problems, male breast growth, increased male pattern baldness, possible harm to prostate health, raised risks for blood clots, congestive heart failure and a worsening of urinary symptoms.
One expert added that, due to these risks, men should be cautious before succumbing to "low T" advertisements. According to Dr. John Amory, professor of medicine at the University of Washington in Seattle, the supplements -- which can cost between $75 to $300 per month -- are currently "being oversold to patients."
In the new study, hypogonadism -- a condition that affects a man's ability to produce normal levels of testosterone -- was diagnosed in about half of the men treated with testosterone therapy, the study indicated.
However, about one-quarter of the men given the hormonal treatment did not have their testosterone levels checked first. Of the remaining 75 percent of men who did have their hormone levels tested, it remains unclear what percentage had low testosterone levels.
"This trend has been driven, in large part, by direct-to-consumer marketing campaigns that have targeted middle-aged men and the expansion of clinics specializing in the treatment of low testosterone or 'low-T centers,'" the lead author of the study, Dr. Jacques Baillargeon, an associate professor in preventive medicine and community health at the University of Texas Medical Branch, said in a university news release.