L-carnitine is an amino acid, and a cofactor that is required for the metabolism of fats and their subsequent transport into the mitochondria, where they undergo oxidation and produce energy.
In the heart muscle, L-carnitine facilitates fatty acid use, and promotes rhythm, myocardial blood flow, and cardiac output. It has also been shown to benefit athletic performance, with studies showing improvements in maximal oxygen uptake, decreased average oxygen consumption, and therefore improvements in running speed.
L-carnitine has also shown to help maintain healthy total cholesterol and triglyceride levels. It also supports general wellbeing, and assists carbohydrate metabolism.