L- carnitine, also known as L-carnitine (CN), is a kind of vitamin nutrient in animal tissues, plants and microorganisms. 1905, Russian scientists Krimberg and Gulewitsch first discovered carnitine from beef extract. Tomita and Sendju confirmed that its molecular structure was L-β- hydroxy-γ-trimethyl ammonium butyric acid (Haeckel et al., 1990). In the late 1950s, Irving Fritz first confirmed that L- carnitine played an important role in β -oxidation of long-chain fatty acids in heart and other muscles (Fritz IB, 1959). Because most healthy animals can produce enough L-carnitine, its importance has long been ignored. It was not until 1980s that L- carnitine was considered as an essential nutrient for human body. From 65438 to 0993, L-carnitine was recognized by the US Food and Drug Administration (FDA) and the World Health Organization (WHO), and the American expert committee confirmed L-carnitine as a "recognized safe and nontoxic substance". From 65438 to 0995, the European Union approved the use of L-carnitine and L-carnitine hydrochloride in various animal feeds. The existing literature shows that L- carnitine is extremely important for the growth, reproduction and health of animals. It has important physiological functions such as promoting fatty acid β-oxidation, reducing serum cholesterol and triglyceride content, and improving body tolerance. With the development of animal husbandry, the synthesis of convenient, safe and efficient growth promoters has been the focus of drug and nutrition research. Adding high copper, antibiotics, β -stimulant and growth hormone for injection into feed has some disadvantages, such as environmental pollution, drug residue, food safety and complicated operation, which makes it difficult to popularize and use it in production. As a new feed additive, L- carnitine has been paid attention to because of its convenient use, which can improve the reproductive performance of sows, the survival rate of piglets, reduce the back fat thickness and improve the quality of meat and eggs under certain conditions, and has also been studied and utilized in medicine and food industry. Carnitine is the best nutrient to lose weight. Without carnitine, there is no fat burning. In order to achieve the ideal degree of fat burning, the body needs an ideal level of carnitine content. In order to let carnitine enter people's lives, scientists in China applied modern high-tech biotechnology to develop various slimming foods that provide convenience for people to lose weight healthily. Beijing Wanboli Science and Technology Development Co., Ltd. undertook the national key scientific research project in the Ninth Five-Year Plan: the research on functional food with high efficiency, intelligence and weight loss. Boli Merlot is a new generation of health, intelligence and weight loss functional food developed by a scientific research team composed of domestic experts, scholars and professors with reference to the latest international technology. The product is rich in lecithin, DHA, L-carnitine and other nutrients needed by human body. By exerting biological nutrition regulation ability, it can improve human memory and thinking ability, enhance muscle strength and prevent and inhibit obesity. And has the characteristics of convenient eating, good taste, remarkable effect and no side effect. Widely welcomed by obese people, students and teenagers.