Creatine has become one of the most popular sports supplements among professional and amateur athletes. In the body creatine is converted to creatine phosphate which helps to fuel skeletal muscles and provides support for immediate energy products during high-intensity workouts. Creatine may very well be the single most heavily researched sports supplement available today. Creatine is a key nutrient that occurs naturally in the body and found in some foods. Creatine functions as an energy source in your muscle cells helping to increase strength and reduce fatigue during intense training.