Doubt the employer would notice it, being that GPA and performance are not necessarily correlated. Doping in any situation gives an edge at the upper levels, but won't make an average person superhuman. (It makes superhumans even more superhuman).

We frown on doping because it's dangerous due to bad health effects. Forcing someone to use performance enhancers to compete and damage their health is the ethical problem in my mind. Collateral harm.