Protein supplements come from many different sources and the answer depends on your goal. If you are looking to supplement protein in your diet, then look for 100% whey protein isolate or soy protein isolates. Whey protein isolate is the purest type of protein and is easiest to digest and absorb, soy protein isolate is almost just as pure and is tolerated better by patients with dairy allergies or intolerances. If you are looking for protein to assist with skin, hair, and joints; collagen is the type that you should look for.