I don't know why you Americans don't use ephedrine still. All these PWOs suck compared to ephedrine. Ephedrine is just the right degree of mental kick for training. I can a bunch of different PEDs easily but ephedrine is almost impossible to source here nowadays.
Maybe becuase it can cause tachycardia. I know a number of cyclists I raced with who used to pop ephedrine before races that were not drug tested. Every one of them, to a person, gave it up because they got sudden bouts of high heart rates, well over 200 resting.
The same thing of course can happen with high does of caffeine, except if you go too high with powdered caffeine you end up dead.