Carnitine is an amino acid that is important for the metabolism of fats, specifically it transports fatty acids into the mitochondria where they can be used as fuel. Through this mechanism carnitine helps to reduce fatty build up in the liver and reduces the amounts of triglycerides in the blood thus reducing heart disease risk. It can be synthesised in the liver providing that sufficient amounts of methionine, lysine, iron and vitamins B1 and B6 are present. Carnitine is often recommended for those suffering from chronic fatigue syndrome (CFS) as a way of reducing fatigue and increasing energy levels. Supplements generally come in two forms - l-carnitine and acetyl-l-carnitine. It is suggested that acetyl-l-carnitine may help to maintain levels of the important neurotransmitter acetylcholine by donating an acetyl group.