The Role of l Carnitine in Mitochondria, Prevention of Metabolic Inflexibility and Disease Initiation The Role of L Carnitine in Distance Athletes L Carnitine Tartrate Amino Acid 1,500 mg Benevolent Nourishment L carnitine is effective for both fat loss and athletic performance. However, oral L carnitine has lower bioavailability and can be harmful at high doses, so it should be avoided. , Even cardiologists