My 15 yr old has some weights in his room which he has been using but he is now saying he wants protein shakes to help him build muscles. At first I acted as though he was asking to take heroin and said definitely not, but having seen that you can buy them in tesco I'm not sure whether it would be too big a problem or not. Some seem to have creatine and caffeine in them which I wouldn't imagine is too good for teenagers but I'm just not sure if to let him try them or not.