Thats the question… where I live the soy protein powder is so much cheaper than whey protein that it doesnt even make sense to consume it.
No. Soy is made from soybeans, whey is made from the part of milk that usually gets discarded when making cheese.
What you mean to ask is, are they equivalent? Or perhaps, are they equally good?
… Also no. Whey is better, largely because it’s amino acid composition favors muscle growth significantly more than soy protein. The degree to which that matters depends, and largely on how much muscle building exercise you’re doing.
Are they almost as good? Yes.