unfortunatly, i can only be kinda vague about this, but i think there are basically two differences... one is the source. soy is plant based protein, if i'm not mistaken. whey is milk based. the other difference is that if you want to build muscle, whey is better. soy either doesn't have as much of some essential protein, or has more of some other thing, which makes it not quite as good. crystal clear?
