Why So Many Guys Are Obsessed With Testosterone

Despite the anecdotal nature of the study, it had a seismic impact on medical practice. Most doctors stopped prescribing testosterone, cautioning that the risk of prostate cancer was too high. That prohibition lasted for the remainder of the 20th century. For roughly 60 years, “there was almost no testosterone given anywhere in this world,” says Dr. Abe Morgentaler, a urologist at Harvard Medical School. When he was a medical student in the 1980s, Morgentaler told me, “I was taught that if a healthy man received testosterone today, he would come back in one month with aggressive prostate cancer.”

Morgentaler, however, was curious about the hormone’s potential. As an undergraduate conducting research, he found that when castrated lizards were given testosterone, their mating dances were restored. Once he was practicing as a urologist, men started coming to him complaining of sexual problems. It was a decade before the arrival of Viagra, and doctors had little to offer. “I thought, Maybe guys are like my lizards,” Morgentaler says. He started prescribing testosterone to a small group of patients, warning them that it could increase their risk of prostate cancer. Desperate, most men went ahead anyway.

To his surprise, many of his patients reported that not only were they now having lots of sex but also that other aspects of their lives had improved. “They’d say, ‘My wife likes me again,’” he recalls. “Another says, ‘I wake up in the morning, I swing my legs over the side of the bed, I have optimism for my day. I haven’t felt that way in 15 years.’” Over the next decade, as Morgentaler spoke about his patients’ positive outcomes at conferences, including preliminary data suggesting no increase in the incidence of prostate cancer, more doctors began following his lead.

But soon after Morgentaler began treating his patients, a new obstacle arose. Doping scandals swept the world of sports, where athletes trying to set records and win Olympic medals were caught taking testosterone and other anabolic steroids at doses much higher than what Morgentaler was giving his patients. In 1990, Congress passed a law adding steroids, including testosterone, to the Drug Enforcement Administration’s list of controlled substances — making the hormone illegal without a prescription and adding new restrictions for doctors.

Then, after a few studies published in the early 2010s suggested that T.R.T. was associated with a potential increase in heart attacks and strokes, the F.D.A. issued a warning label for testosterone products. As part of the warning, the agency required drug makers to fund what would become the largest randomized, placebo-controlled trial to investigate the risks and benefits of T.R.T.