L-carnitine is a chemical that is made in the human brain, liver, and kidneys. It helps the body turn fat into energy. It is important for heart and brain function, muscle movement, and many other body processes.
L-carnitine is used to increase L-carnitine levels in people whose natural level of L-carnitine is too low. Some people also use L-carnitine for conditions of the heart and blood vessels, serious kidney disease, and many other conditions, but there is no good scientific evidence to support these uses.