In living cells, carnitine is required for transporting fatty acids from the cytosine to the mitochondria during the breakdown of fats for generating metabolic energy. This vitamin also belongs to the group of B vitamins. It is widely available as a nutritional supplement. Carnitine exists in many forms such as D-carnitine, L-carnitine, DL-carnitine as well as acetylene-L-carnitine but its biologically active form is L-carnitine, whereas the inactive enantiomer is D-carnitine.

It is therefore important for the supplying of energy in the cells, as well as muscles, helps in prevent fatty build-up in areas such as the heart, liver, and skeletal muscles.
It even reduces the risk of poor fat metabolism in diabetes, alcohol-induced fatty liver as well as the risk of heart problems. With the help of carnitine, there is improvement in the antioxidant effect of vitamin C as well as E.

L-carnitine supplements are used to increase L-carnitine levels in people whose natural level of L-carnitine is too low because they have a genetic disorder, are taking certain drugs (valproic acid for seizures), or because they are undergoing a medical procedure (dialysis for kidney disease) that uses up the body’s L-carnitine. It is also used as a replacement supplement in strict vegetarians, dieters, and low-weight or premature infants.

L-carnitine is used for treating the conditions of the heart and blood vessels including heart-related chest pain, congestive heart failure (CHF), heart complications of a disease called diphtheria, heart attack, leg pain caused by circulation problems, and high cholesterol.

Some people use L-carnitine for muscle disorders associated with certain AIDS medications, difficulty in fathering a child (male infertility), a brain development disorder called Rett syndrome, anorexia, chronic fatigue syndrome, diabetes, overactive thyroid, attention deficit-hyperactivity disorder (ADHD), leg ulcers, Lyme disease, and to improve athletic performance and endurance.