Originally Posted by 79pmooney

And those with naturally high hematocrit. Those with natural levels close to 50% would set off alarms if they touched EPO. Armstrong was naturally ~30% as I recall, so he could absorb lots while they were testing for hematocrit levels; not having a good EPO test yet. Also different riders responded differently to a given dosage. So some were huge benefactors, others saw virtually no benefit, some going from being born GC riders to also-rans when EPO took over.