Sports supplements haven't been tested on teens and kids. But studies on adults show that the claims of many supplements are weak at best. Most won't make you any stronger, and none will make you any faster or more skillful.

Many factors go into your abilities as an athlete including your diet, how much sleep you get, genetics and heredity, and your training program. But the fact is that using sports supplements may put you at risk for serious health conditions. So instead of turning to supplements to improve your performance, concentrate on nutrition and follow a weight-training and aerobic-conditioning program.