What is L Carnitine? L Carnitine is a naturally occurring amino acid derivative that the human body can synthesize itself. It is mainly found in red meat and dairy products. [1] Core Benefits of Carnitine Rich Foods: Understanding L Carnitine and Its Benefits Loyal Essential L Carnitine Optimal Health Systems Beef helps body use fat as energy Foods High in L Carnitine for Energy and Health Marnys Carnitine: the claims and why it may not work