Doping

Maybe, maybe not. But there is a limit in place and Froome has broken that.

Poor medical advice or carelessness may be the root cause, but it’s not good for Froome or the sport.

Marginal gains. I’ve heard of people titrating doses to lean on the legal limit to exploit every last “legal high”, if you will.

I don't really know anything about the subject, but this suggests it is permormance enhancing.

But indeed that doesn't yet mean he would've taken more of it than allowed.