America's Compounding Center says the following about L-carnitine:
"Carnitor, also known as L-Carnitine, levocarnitine, and carnitine, is an amino acid that is naturaly produced in the liver and kidneys and is stored primarily in the muscles, heart and brain. It helps the body convert fat into sources of energy. Dietary sources of carnitine include meats (particularly red meat) and dairy products. Carnitine deficiency is rare, since the body usually produces an adequate amount, and is often due to a genetic defect, such as mitochondrial disease. Premature infants who are fed exclusively formula that does not contain carnitine may also become deficient. Symptoms and complications associated with carnitine deficiency may include muscle weakness, liver problems, heart failure, and hypoglycemia. ...The typical dosing range for patients wth mitochondrial disease is 30-100mg per kilogram daily. The UMDF recommends starting at 30mg/kg/day, and increasing to a maximum of 10mg/kg/day. Side effects associated with carnitine therapy include stomach upset, diarrhea, body odor, and rash. Carnitine may also increase the risk of seizures in patietns with a history of seizures."