I believe metformin together with diet and exercise helped me to lose weight, since metformin helps reduce insulin resistance. Without metformin I do not lose weight and I still have alot of weight to lose. However metformin can also deplete vit B12 levels. My own B12 levels were lowish before becoming T2 10 years ago. Last year I needed a B12 injection as I became deficient. I won't take metformin anymore. If I stay fat forever then so be it, the effects of B12 deficiency weren't pleasant.