How old is your child? I would be careful with herbs for children just like conventional medicene, their systems are immature and don't handle drugs whether it be herbs, homeopathy or conventional very well. Kids have more reactions up to a certain age, I was a medication nurse and too many people think there is a magic bullet out there for everything and if he seems healthy and normal otherwise why put something in the body that doesn't need to be there? Why not get him into strength training, lift 1lb weights to give him some muscle tone? Helping the body doesn't always have to be something like a pill it could be strength and cardiovascular excersise. There are some good protein foods to add to the diet as well, protien builds muscle along with calcium and vit D.