MET, introduced in 1957, has established itself as the first-line treatment for type 2 diabetes mellitus, due to its ability to reduce hepatic glucose production and improve insulin sensitivity in peripheral tissues, thereby lowering blood glucose levels without causing hypoglycemia or inducing weight gain, being particularly suitable for overweight patients; in addition, it has benefits for the lipid profile by reducing triglycerides and low-density lipoprotein (LDL) cholesterol [35]. This evidence concerns the gene INS and type 2 diabetes mellitus.