It doesn't do much for me either, unless it's really super-high in caffeine. The pediatric neurologist once told me to try giving it to ds when he was younger. At the time ds was about 6 and was literally attempting to climb the walls of the waiting room. Seems caffeine can have the opposite effect on hyper kids and calm them down.
For what it's worth, ds hates the taste and refuses to drink it so I don't know if it works or not!