Re thinking red meat: what's the beef? 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 plays crucial role in energy production esp for the heart, fueling mitochondria (cell furnaces). Highest food source? Only animal food, especially red meat; lamb and beef are best. (Redder the Beef helps body use fat as energy