Carnitine is a quaternary ammonium salt which is synthesized from the amino acids lysine and methionine.
This is done mainly in the liver and in the kidneys. Carnitine is responsible for the transport of fatty acids from the cytoplasm to the mitochondria, the energy of the producer cell. The natural form - and the only one with biological activity - is the optical isomer L-carnitine (or levocarnitine).
Carnitine plays an important role in energy production in the body. Furthermore, an antioxidant, and carnitine has a protective effect on the heart and blood vessels. The acetylated version, acetyl-L-carnitine, is particularly active in the brains and it has a similar function. Carnitine is found in all tissues of the body.