L Carnitine Benefits, Uses, Dosage, Foods, Side Effects Dr. Axe L carnitine known as the energy nutrients, provides massive benefits to your heart and works best with Alpha Lipoic Acid. Foods High in L Carnitine for Energy and Health Marnys L Carnitine Injection Levocarnitine IV 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 Doctor's Best L Carnitine Fumarate with Biosint Carnitines, 855 mg, 60