L-Carnitine helps the body produce energy. It is important for heart and brain function, muscle movement and many other body processes. It helps the body converts fat into energy. Carnitine plays an important role in preventing fat, especially in the heart, liver and skeletal muscles. Carnitine supplements are used to help people with carnitine deficiencies. It may increase the oxygen supply to the muscles. It may reduce muscle soreness after exercise. It helps to decrease muscle pain and damage, potentially helping reduce recovery time and post-workout muscle soreness.