L Carnitine is used to prevent and treat a lack of L Carnitine It is used to prevent and treat this condition in patients with kidney disease on dailysis It is given to people whose body cannot properly use L Carnitine from their diet Lack of L Carnitine can lead to liver heart and muscle problems Your doctor may treat lack of L Carnitine by prescribing L Carnitine for you L Carnitine comes in two forms L Carnitine should not be confused with the D L L Carnitine form labeled as vitamin B T Only the L form of L Carnitine is used by the body to treat serious L Carnitine deficiency The D L form does not help the body use fat and can actually interfere with and cause a lack of L Carnitine Certain L Carnitine products have been specifically approved by the U S Food and Drug Administration for medical use and are available only with your doctor s prescription Once a medicine has been approved for marketing for a certain use experience may show that it is also useful for other medical problems Although this use is not included in product labeling L Carnitine is used in certain patients with the following medical condition L Carnitine deficiency that results from treatment with valproic acid