INS and type 2 diabetes mellitus: Metformin is the first choice drug treatment for T2DM; in a UK Prospective Diabetes Study (UKPDS study), when compared with the “conventional” group (i.e., patients treated with diet alone or in combination to chlorpropamide, glibenclamide, or insulin), the series of metformin-treated patients showed significant risk reductions of 32% for any diabetes-related endpoint, 42% for diabetes-related death, and 36% for all-cause mortality in overweight patients [2].