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 give IV L Carnitine Tartrate (60 capsules) New Beginnings Nutritionals Codeage Liposomal L Carnitine+ Supplement 500 mg L Carnitine L Tartrate per Serving Form Amino Acid Carbamide Forte L Carnitine Tartrate Supplement 1000mg NUTRABAY