Davis says an increase in advertising for hormone-replacement drugs has led to lots of unnecessary treatment.
"Between 2000 and 2011, testosterone use increased at least 3-fold in the United States," Kravitz wrote. "Many men who were treated with these products did not undergo appropriate testing for testosterone deficiency or meet diagnostic criteria for hypogonadism."
Kravitz said the ad blitz, which began around 2000, preceded professional guidelines for physicians and product-safety research.
The ads work
If nothing else, Kravitz said the response proved the effectiveness of advertising. "Patients respond to [direct-to-consumer-advertising] and physicians respond to patients," he said.
He cited research which found that a single television advertisement for testosterone replacement therapy produced 14 new tests, 5 new initiations, and 2 initiations without testing per 1 million men exposed.
When medical research began to link testosterone replacement therapy with cardiovascular disease, the number of ads for these products declined starting in 2014, likely due to U.S. Food and Drug Administration requirements for informing consumers in drug advertising about potential risks, according to Kravitz.
"But with revenue from topical testosterone products topping $2.2 billion the year before, the market for androgen replacement therapy was still substantial," he wrote.
Kravitz notes that many medical experts would like to see restrictions on direct-to-consumer ads, but he concedes that a complete ban is unlikely given free speech protections. He recommends continued research on the topic, since direct-to-consumer advertising, "while a potentially powerful tool in motivating patient behavior and perhaps even physician prescribing, does not necessarily serve to improve the health of patients or the public."
Low T
Low testosterone levels -- hypogonadism -- increases with age and can cause symptoms such as low libido, reduced strength, fatigue, and depression. It is diagnosed with a blood test together with clinical symptoms and signs.
It is treated with products that increase levels of male-reproductive hormones known as androgens, most often testosterone, through injections, gels, transdermal patches, or subcutaneous pellets.