Doping

It is only introducing a banned substance if the substance is banned although it is still clearly sailing close to what looks like a dodgy procedure.

Blood doping is banned too. That doesn't introduce anything that wasn't already there. It doesn't mean it's not performance enhancing.

I meant that the blood spinning is meant to increase the level of hormones as well as red blood cells in the blood. This artificial increase in testosterone, for example, from the blood spinning would surely replicate the results of just injecting testosterone.
I think I'm trying to say that although its 'just blood spinning' it would have the same effect as just straight up doping