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. The Science of Carnitine: How It Works and Why It Matters How L Carnitine Helps with Fat Metabolism L Carnitine and Weight Loss: Does This Fat Burner Really Work? Health Guide Does L Carnitine Really Work? An Honest Guide The Science of Good Health