He's too good to be doping in some respects. PEDs are almost exclusively old drugs, often very old, and what known substance could give him this exceptional advantage, allow him to evade attention, and no one else is taking it? EPO is a dynamite PED but the whole peloton / UCI knows that inside out.
I mean Occam's razor and all that, and something completely new is not out of the question. The Balco case in the US was one amateur, but very knowledgeable, steroid chemist making a new substance that could not be detected because analysts didn't know what to look for. Marion Jones won 3 gold medals on the back of it but that is a very unusual case.
Pushes one billion dollars to develop a legitimate pharmaceutical with the majority of that back-loaded onto the cost of human clinical trials. Taking a PED someone's made in their garage is a pretty wild risk, even in the distorted world of elite sport.