Carnitine Deficiency: What Is It, Causes, Symptoms, and More Osmosis How L Carnitine Helps with Fat Metabolism 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 Meet L Carnitine a naturally occurring amino acid that plays a key role in helping the body convert fat into usable energy. It works by transporting fatty acids into your cells to