目前在美国二甲双胍还没有被FDA批准用于减肥，但初步研究证明有轻到中度效果（尤其是糖尿病患者）。

（转）In conclusion, metformin does have a modest effect on weight loss in patients with T2D, PCOS, and possibly in overweight and obese euglycemic patients. More studies, especially randomized controlled trials, are needed to determine the duration and dose of metformin and potential long-term adverse effects in patients without T2D. Patients should be advised that metformin is unlikely to cause a drastic decrease in weight, and lifestyle modifications should be recommended. Renal function and blood glucose should be monitored in patients receiving metformin.