When to Take L Carnitine for Optimal Training Benefits Transparent Labs 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 L Carnitine Benefits for Fat Burning and How to Use ICONFIT 3 Benefits of L Lysine & How to Use It Lysine: Sources, Metabolism, Physiological Importance, and Use as a Supplement