That was mistake number one, Joyner says. Even if most racing happens well below VO2 max territory, the racing that matters—mountain-top finishes and time trials—happen much closer to VO2 max. Mistake number two: Ignoring that boosting your VO2 max can lead to other benefits, such as a jump in your lactate threshold. “They don’t realize that your lactate threshold is a percentage of your VO2 max,” he says. “If your LT [lactate threshold] normally is 80 percent of VO2 max, and your VO2 max goes up, it’s 80 percent of a higher number. Your performance improves.”

What about a real world example? Luckily for us, Captaintbag—a mysterious cycling blogger—has done the math. The numbers are solid, and based around one very basic relationship, Joyner says. Haemoglobin—a protein which carries oxygen—and your VO2 max are naturally linked. Captaintbag can estimate the changes in a rider’s haemoglobin based on how much EPO he is taking (or blood he is transfusing). From there, he can predict the rider’s new VO2 max and threshold power. In other words, he can tell you how quickly a rider can race clean, and on the program.

The numbers are startling. In one example, Captaintbag looked at the power output of domestic pro cyclist Brad Huff and put him on three simulated doping programs—a very-low dose that probably wouldn’t get you caught, a medium-dose (which might also fly under the radar), or a high “Postal” dose. 

The results: From putting out 4.875 watts/kg at threshold, Huff could see his numbers rise to 5.25 watts/kg on the very-low dose program, 5.44 watts/kg on the medium dose, and 5.74 watts/kg on the “Postal” program—up to a 17 percent increase. “Presumming that he’d still be wurth [sic] a damn after 4hrs/ he’s not quite winning GTs [grand tours like the Tour de France]/ he’s a sprinter anyways/ but its [sic] a likely ticket to europe [sic],” Captaintbag writes in verse.

THE BOTTOM LINE: There’s no denying that EPO enhances performance. In fact, it can turn low-level pros into world class riders.