L-carnitine is an amino acid found abundantly in heart and skeletal muscles. It promotes energy production in cells by transporting fatty acids into mitochondria, intracellular structures that generate metabolic energy in the form of Atp. In this role, L-carnitine helps the body metabolize fat efficiently. Fumarate is a naturally occurring compound in the body. Fumarate serves as an intermediate in the Krebs cycle, a key energy-producing process that takes place in mitochondria. L-carnitine helps promote oxygenation of heart muscle and may enhance exercise recovery.