L-Carnitine is the chief amino acid that helps the body convert fats into energy. It can be stored in many areas, from the muscles and the brain, to the heart, and sperm, but it is manufactured by the kidneys and liver. Carnitine is the subject of many studies due to the fact that it is important in the production of energy and the oxidation of fatty acids. It is common to find large amounts of carnitine in the heart because the heart uses the carnitine to turn fatty acids into energy which it then uses to push blood throughout the body.