Out of competition testing would catch that. So you can't "get away" with anything by doing that. There is no incentive for "Big Pharma" to dabble in individual athlete's PEDs. They can make billions and billions more dollars creating proprietary cancer and AIDs medications for the masses. All these PEDs are small-time companies and criminals just looking to make quick money and corrupt athletes / coaches / training programs. The impetus doesn't come from the doctors / scientists - they only respond to the niche demand.