What is l carnitine l carnitine is an amino acid naturally produced in the liver and kidneys stored in skeletal muscle the heart and brain the main dietary sources of l carnitine are red meat and dairy products why use l carnitine l carnitine is a high quality supplement providing 1000mg of l carnitine per serving who can benefit l carnitine is an ideal supplement for those looking to increase their l carnitine intake to be taken as part of a varied and balanced diet and a healthy