L Carnitine: Benefits, Side Effects, FAQ, Sources, and Dosage Supplements don't replace the workbut they can support it L Carnitine helps your body turn fat into usable energy, so you can push harder and recover better. Consistency first. Supplements second. Results 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. L Carnitine Dosage Explained: A Complete Guide The Science of Good Health