Carnitine is not an amino acid and it does not in fact contain the amino group (NH2). Carnitine is a coenzyme, a water-soluble vitamin-like compound. And this carnitine is similar to choline, one of the B vitamins-and, like various B vitamins, carnitine helps us turn food into energy. More specifically, it is essential for the burning of long-chain fatty acids. L-carnitine is thought to be one of the safest nutritional supplements on earth. The heart depends on adequate concentrations of carnitine for normal heart function.