The morning after I took my first dose, I woke up with a strange headache, a very distinct kind of pain that I would come to associate with EPO. It defied all manner of ibuprofen and aspirin but gradually went away.

Within three weeks, my hematocrit level had risen to 48.3. By this time, my testosterone levels had shot up to 900 nanograms per decaliter, from a previous mark of 280. (My starting level was just below normal.) My HGH had increased only slightly, which Dr. Jones found unusual. He upped my HGH dosage to 1.2 IU a day, speculating that the long hours I spent training might be keeping the level down.

Despite these measurements, I remained skeptical about all the drugs until March 29, when I rode an event along the central coast of California, the Solvang Double Century, at what for me was a fast and hard pace, finishing in around 11.5 hours. About ten hours in, it dawned on me that something was definitely happening. Sure, I'd been training hard, but I'd done enough of that to know what to expect. All around me were riders—good, strong riders—who looked as worn out as you'd expect after ten hours in the saddle. I was tired, but I felt curiously strong, annoyingly talkative and fresh, eager to hammer the last 40 miles. The last time I'd ridden 200 miles, I felt awful the next day, like I'd been hit by a truck. After the Solvang race I woke up and felt hardly a touch of soreness. I also felt like I could easily ride another 200, and I realized that I'd entered another world, the realm of instant recovery. I'll be frank: It was a reassuring kind of world, and I could see why people might want to stay there.

When I checked in with the good doctor soon after the race, he wasn't surprised about what I'd experienced. "With your hematocrit levels higher, you don't produce as much lactic acid, which means you can ride harder, longer, with less stress. The growth hormone and testosterone help you recover faster, since you're stronger to start with and recover more quickly. All those little muscle tears repair much more quickly."

He shrugged. "It works," he said. "It always works."

It all started to make sense. Feeling like I did after the 200-miler would be a huge advantage in a long stage race like the Tour de France. I understood what five-time Tour winner Jacques Anquetil meant back in 1967 when he said, "You'd have to be an imbecile or a hypocrite to imagine that a professional cyclist who rides 235 days a year can hold himself together without stimulants."

Back then, "stimulants" mostly meant amphetamines, which kept riders going through day after day of hard stages. The new drugs had the same rejuvenating effects but simply worked much better, without the crash and depression of uppers.

I began to adjust my training schedule for harder rides and less rest and I felt fine. It wasn't a huge difference—I added about 10 or 15 percent more effort to my training—but had I been competing at a top level, it would have represented a major advantage.