If you're putting in the work but the scale isn't moving, your body might just need a little help tapping into its fat stores. That's where L Carnitine comes in. It's not a Does L Carnitine Work for Fat Loss? A Dietitian Explains The Science of Carnitine: How It Works and Why It Matters L Carnitine Liquid Benefits Explained: A Guide The Science of Good Health L Carnitine is Underrated. New Meta Review Reminds Us Why. L carnitine is a naturally occurring amino acid structure that is made in the human brain, liver, and kidneys. L carnitine plays a critical role in energy production, as it converts fat into energy.