This is just like diuretics at this point. Sure, you can use diuretics to cut weight but you can also use them to hide PED use. That's why they are banned. This "tainted supplement" BS is just a great cover for when your designer steroid that has yet to have a test developed for it gets mixed in with some random steroid you are not taking because the underground lab that made it didn't clean their beakers/vats well enough. They can use these supplements if they feel like it BUT if something comes up on your test even if it is a 1 trillionth then, fuck you, you are suspended just as badly as someone juiced to the gills.