For some people just eating a balanced diet and doing resistance training is not enough to bulk up, they need a nutritional supplement to provide a lift.
Consuming a Creatine supplement can give a person 2 to 3 times the amount that could be obtained from a very-high-protein diet.
Some personal trainers recommend nutritional supplements to their clients. In this New York Times article a personal trainer explains how Creatine works.
If you’re looking to bust through a plateau, taking five grams of creatine before your workout might help you do that,” said Steve Hoffman, a trainer in Cherry Hill, N.J. “It adds water weight to your muscle and helps you lift more.