Other drugs used to treat type 2 diabetes to lower the blood sugar such as metformin, sulfonylureas, thiazolidinediones, dipeptidyl peptidase-4 (DPP-4) inhibitors, and sodium-dependent glucose transporter 2 (SGLT2) inhibitors, have undesirable side effects, do not correct the underlying issues, and need to be continually taken [158]. This evidence concerns the gene DPP4 and type 2 diabetes mellitus.