Metformin is a glucose-lowering drug, not a weight-loss drug, and is not recommended for healthy people to use metformin for weight loss. Metformin has a certain effect of reducing weight while lowering blood sugar, but how long you will lose weight when taking it is related to personal constitution and daily habits, and there are individual differences. Generally the heavier the weight, the more obvious the effect will be, and most patients can see weight loss within 1-2 weeks of taking the drug. Metformin is the first-line basic drug for overweight and obese type 2 diabetic patients to control hyperglycemia. Its main pharmacological effects are to inhibit glycogen isogenesis and glycogenolysis, reduce the output of hepatic glycogen and lower blood glucose, and also improve the ability of muscle and adipose tissue to transport glucose and promote the uptake and utilization of glucose. Metformin can delay gastric emptying, inhibit the satiety center of the central nervous system, and some patients have gastrointestinal reactions such as nausea and vomiting, and this reaction of reducing appetite and food intake can play a role in weight loss to some extent. Generally, the higher the BMI, the better the weight loss effect, and some patients can lose up to about 3 kg in the first 3 months. It should be noted that for people who do not have a high body mass index, they may not experience weight loss even when taking metformin.