The position statement of the American Diabetes Association (ADA) and European Association for the Study of Diabetes (EASD) recommends the use of one of six commonly used antihyperglycemic agents i.e. 1) a sulfonylurea, 2) a thiazolidinedione, 3) a dipeptidyl peptidase-4 (DPP4) inhibitor, 4) a sodium-glucose cotransporter-2 (SGLT2) inhibitor, 5) a glucagon-like peptide-1 (GLP-1) receptor agonist, or 6) a basal insulin analogue, as an add-on therapy when the individualized HbA1c target is not achieved after ~3 months of treatment with metformin alone (1). This evidence concerns the gene GLP1R and diabetes mellitus.