This would probably be better answered on the fitness and exercise board. I only know after exercise. I'm not sure if it's after weights or total workout. I think most people tend to do all their cardio and then their weights, so then it would be easy. You are, technically, still using a lot of your muscles when doing cardio, so if I had to take a guess, it would be after total workout. Plus, who wants to do cardio after drinking a shake?