Pharmaceutical Grade. Increase Endurance. Build Muscle. Burn Fat. Recover Faster. L-Carnitine is a naturally occurring amino acid that plays an essential role in converting fat into a usable energy source. by enabling the body to use fat as fuel, L-Carnitine supplementation promotes increased metabolism and workout performance. Key Benefits of L-Carnitine: Promotes Fat Loss, Helps Convert Fat Into Energy, Promotes Increased Metabolism, Supports Increased Energy, Stimulant Free.