The barrage of advertisements targets older men. "Have you noticed a recent deterioration of your ability to play sports?" "Do you have a decrease in sex drive?" "Do you have a lack of energy?"
If so, the ads warn, you should "talk to your doctor about whether you have low testosterone" — "Low T," as they put it.
In the view of many physicians, that is in large part an invented condition. And while ads like those from AbbVie Pharmaceuticals have buoyed sales of testosterone gels, that may be bad for patients, experts say.
Sales of prescription testosterone gels that are absorbed through the skin generated over $2 billion in American sales last year, a number that is expected to more than double by 2017.
"The market for testosterone gels evolved because there is an appetite among men and because there is advertising," said Dr. Joel Finkelstein, an associate professor at Harvard Medical School who is studying male hormone changes with aging. "The problem is that no one has proved that it works, and we don't know the risks."
Dr. Eric Topol, a cardiologist at Scripps Health in San Diego, is alarmed by the percentage of patients he sees who use the roll-on prescription products, achieving testosterone levels that he described as "ridiculously high."
The gels are of questionable medical benefit for many of the millions of men who now take them, he and other doctors say, and their side effects may well prove dangerous.
"These medicines come with a risk of coronary artery disease," Topol said. Other side effects include an enlarged prostate, he added.
Patients of any age may benefit from testosterone replacement if their levels are severely low because of serious medical problems, experts say. But testosterone normally declines as men age — just as estrogen does in women, Finkelstein said. Low testosterone is rarely the main cause of erectile dysfunction.
The FDA has approved the gels "for use in men who either no longer produce the male sex hormone testosterone or produce it in very low amounts." Should testosterone be replaced in older men, and will it safely redress frequent ordinary symptoms of male aging, like decreased muscle mass and libido? And what constitutes a very low amount?
Finkelstein said, "Until there are big, long-term studies to address the issues of testosterone replacement, we're not ready to make recommendations on that."