An ergogenic acid normally derived from meat, known as creatine, plays an important role in energy production. Creatine supplements (available in powdered, liquid and serum form) enable weight trainers to lift heavier weights, and to hold them for longer, as they produce greater contractions in the muscles, the muscles also look larger, as more water is drawn into them. However, effects of creatine are short term, as the body's storage of the acid is limited.