Some protein shakes use aspartame sucralose and other harmful excitotoxins to enhance flavor. Watch out these can effect circulation and metabolic processes.
suggested reading. http://www.brainsupplements.com/protein.htm
Someone I know that requires extra protein (some kinda post-surgery reason, her body doesn’t process it as efficiently as it did pre-surgery) absolutely insists on whey protein powder. I can’t say why exactly, but she’s pretty smart (Mom) so I believe her.