Carnitine Deficiency: What Is It, Causes, Symptoms, and More Osmosis Ingredient Spotlight: L Carnitine Source: Biosynthesised in the body from the amino acids Lysine and Methionine, L Carnitine is a conditionally essential nutrient involved in energy metabolism and fat transport. Key Benefits Acetyl L carnitine physical chemical, metabolic, and therapeutic properties: relevance for its mode of action in Alzheimer's disease and geriatric depression Molecular Psychiatry Carnitine, Acylcarnitines and Beta Oxidation