The Role of l Carnitine in Mitochondria, Prevention of Metabolic Inflexibility and Disease Initiation L Carnitine for PCOS: Everything You Need to Know PCOS Nutrition Center What is L Carnitine, L Carnitine is an amino acid that plays a role in energy production and fat metabolism. Its found in foods like red meat, fish, and dairy, and also available as a supplement., L Carnitine: Benefits, Side Effects, FAQ, Sources, and Dosage