Functional differences between l and d carnitine in metabolic regulation evaluated using a low carnitine Nile tilapia model British Journal of Nutrition Cambridge Core Meet L Carnitine a naturally occurring amino acid that plays a key role in helping the body convert fat into usable energy. It works by transporting fatty acids into your cells to Carnitine transport and fatty acid oxidation ScienceDirect The Importance of the Fatty Acid Transporter L Carnitine in Non Alcoholic Fatty Liver Disease (NAFLD)