I've read different things on this one. What do you guys think? Should a whey shake be drank before or after a workout?
Whey protein can be effective, but you'll have to give more information on your diet and workouts in order to get an intelligent response.
Whey protein does effect insulin levels mainly if drunk alone or with carbs, i.e with no other protein (like casein) or with fat. Therefore pre-workout ain't so great. That's maybe open to debate though...
Whey protein is best consumed after a workout with carbs. Carbs in fact are the primary requirement BEFORE protein which most people just don't get. I think it was Charles Poliquin who wrote that most people would put on more mass using carb powder than protein powder, which I think means basically without sufficient carb intake particularly after workouts it won't matter if you drink a bucket of protein. Think of using protein powder without enough carbs to accompany it like taking creatine and expecting to grow on a 600 calorie diet.
You do see lots of skinny people sipping protein drinks after workouts and not carb protein mixes.
But Protein comes a close second and you need to drink both really without any fat which would delay absorption.