GLP-1 receptor agonists are now used for the treatment of type 2 diabetes and obesity. Looking back, GLP-1 was found to be a cleavage product of proglucagon processing.A key breakthrough came from the discovery of exendin-4.Exendin-4 is a peptide with agonistic properties at the GLP-1 receptor but resistance to degradation by DPP-4.Semaglutide, the first oral GLP-1 receptor agonist, marked the next milestone. https://www.medicilon.com/videos/glp-1-receptor-agonists-evolution/