Currently, there are various GLP-1 analogs approved for the treatment of type 2 diabetes (T2DM) which were developed from human GLP-1 backbone (_glutide) (e.g., albiglutide, dulaglutide, liraglutide, and semaglutide) and exendin-4 backbone (_natide) (e.g., exenatide, efpeglenatide, and lixisenatide) (Table 1). This evidence concerns the gene GCG and type 2 diabetes mellitus.