L-carnitine can be taken within a few days at the earliest to see some weight loss results. The main pharmacological effect of L-carnitine on weight loss is to promote the metabolism of fatty acids. The effect is relatively fast, usually within 1 hour of taking it, and the effect can be maintained for about 6-8 hours, and the weight loss effect can be achieved after several days of continuous use. However, for the vast majority of users, once the drug is discontinued, it will rebound. In fact, whether the body will gain weight is closely related to the relationship between intake and consumption of energy, if the intake of energy is less than the consumption of energy can also achieve the effect of weight loss. It is recommended to eat a light diet during the weight loss period, eat more fresh vegetables and fruits rich in vitamins, and not to eat too greasy and spicy food. In addition, any drug has a certain degree of toxicity, and it is easy to rebound after stopping the drug, so it is not recommended to apply drugs for weight loss.