Metformin for the prevention of T2D •Most studies assessing the role of Metformin in preventing T2D in youth have focused on indices of insulin resistance rather than progression to overt T2D. •Evidence regarding the effect of Metformin on insulin sensitivity and glycemic control in obese youth with markers of insulin resistance is inconsistent. •Long-term studies focusing on prevention of progression to T2D are required. This evidence concerns the gene INS and type 2 diabetes mellitus.