Carnitine Deficiency: What You Need to Know The Medical Biochemistry Page 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 Carnitine Molecule of the Month September 2003 The benefits of L Carnitine in sports SPONSER SPORT FOOD AG L Carnitine Linus Pauling Institute Oregon State University From brain to muscle, L Carnitine plays a key role in energy metabolism, endurance, and recovery by supporting efficient fat to energy conversion.