The discovery of glucagon-like peptide-1 (GLP-1; a 30-amino-acid peptide hormone) has become one of the great discoveries of the twentieth century as its discoverers (Joel Hebener, Svetlana Mojsov and Lotte Bjerre Knudsen) and developers of GLP-1 receptor agonists (GLP-1RAs) to target obesity and type 2 diabetes mellitus (T2DM) have been awarded 2024 Lasker-DeBakey Clinical Medical Research Award [1,2]. Here, GCG is linked to diabetes mellitus.