L-carnitine, also known as L-carnitine and vitamin BT, has the chemical formula c7h15no3 and the chemical name is (R) - 3-carboxyl-2-hydroxy-n, N, n-trimethylpropylammonium hydroxide internal salt. The representative drug is L-carnitine. It is a kind of amino acid that promotes the conversion of fat into energy. The pure product is white crystal or white transparent fine powder. It is very soluble in water, ethanol and methanol, slightly soluble in acetone, but insoluble in ether, benzene, chloroform and ethyl acetate. L-carnitine is very hygroscopic, has good water solubility and water absorption, and can withstand high temperatures above 200 ℃. It has no toxic and side effects on human body. Red meat is the main source of L-carnitine, which can also be synthesized by human body to meet physiological needs. It is not a real vitamin, but a substance similar to vitamins. It has many physiological functions such as fat oxidative decomposition, weight loss and anti fatigue. As a food additive, it is widely used in infant food, weight loss food, athlete food, nutritional supplements for the middle-aged and elderly, nutritional fortifiers for vegetarians and animal feed additives.