Metformin is the first-line basic drug for blood glucose control in overweight and obese type 2 diabetic patients, with a strong effect of lowering blood glucose, generally taking effect 2-4 hours after taking. In addition, it also has a certain effect of weight reduction, the effect of weight reduction is related to the patient’s weight, individual differences, but most of the effect can be seen within 2 weeks. Metformin blood concentration time is 2 hours, the average plasma concentration drug clearance half-life is about 4 hours, probably half-life of 1.7-4.5 hours, can reach steady-state plasma concentration in 24-48 hours, so the onset of action time is mostly in about 2 hours after taking the drug, it takes 1-2 days to better control blood sugar. For the weight loss effect, generally the higher the body mass index, the better the weight loss effect, some patients can lose up to 3kg in the first 3 months, while for the people who do not have high body mass index, may not appear weight loss even after taking metformin. It is recommended that patients taking metformin to lower blood sugar, if there is no significant control after using the drug, do not rush first, you can continuously monitor blood sugar, record the blood sugar value, and adjust the glucose-lowering treatment under the guidance of a specialist.