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 Levocarnitine Oral Solution USP (1g per 10mLmulti dose) Role of L carnitine in exercise training: Anti inflammatory, antioxidant, and metabolic interactions ScienceDirect Carnitine: the claims and why it may not work