But the medical establishment wouldn’t have had much luck had demand not spiked as well. In a way, the juicing scandals in sports served as a perverse advertisement for the drugs’ effectiveness. We saw the home-run totals, we saw the muscles and we saw the guys who looked as if they were having a whale of a good time with their Adonis bodies — until they pushed it too far and started looking ridiculous, like Barry Bonds, whom one insider dubbed “the Michelin Man” for his bulging neck.

The truth is that a big part of steroids’ attraction was always mental. Jason Giambi, an admitted juicer who now plays for the Colorado Rockies, once told me the key to being a big-league hitter was to “feel sexy” up at home plate, and he meant it far more literally than I understood at the time. Extra testosterone does a lot for the body, but it also gives an athlete a feeling of being unstoppable, of having an edge, of feeling, well, sexy. It’s this feeling that many men at home watching “low T” ads during the recent baseball playoffs want for themselves.

It’s not just sports. People laughed when Sylvester Stallone was arrested in Australia in 2007 for trying to transport his personal stash of growth hormone, but its use is reportedly widespread among actors of a certain age looking to keep a youthful appearance.

Of course, millions of men (and women) remain, to say the least, wary of such treatments. Dr. Morgentaler, a self-described testosterone skeptic when he began researching it more than 20 years ago who later became an advocate, believes that the stigma was created unfairly. “People have the idea that stuff is illicit and illegal and dangerous,” he said. “But really the story in sports is that it’s against the rules of whatever game it is.”

He has a point. But I remember interviewing an East German athlete outside a Berlin courtroom in 1999. She was one of many plaintiffs in a case against Manfred Ewald, the former East German sports boss, who had given orders to give underage female athletes large doses of steroids without their knowledge, leading to a wide array of health problems, including giving birth to babies with club feet. “Steroids are a time bomb,” she said. “They are always dangerous. I would tell athletes around the world, ‘Keep yourself off steroids.’ ”

Then again, there’s a difference between sluggers shooting themselves up to reach testosterone levels 50 times above normal — consequences be damned — and low-level supplements that can improve quality of life with a minimum of health risk.