Bioactive peptide-based active pharmaceuticalingredients (APIs) not only have proven antihyperglycemic potentialagainst T2DM by enhancing insulin release via activation of the glucagon-likepeptide-1 receptor (GLP-1R) but also suffer from unwanted side effectsof induced obesity by suppressing glucagon (GCG) release.21 Thus, single receptor agonist (monoagonist)peptide APIs face unmet challenges in the treatment and managementof T2DM,20,26 requiring peptide APIs targeting and activatingboth GLP-1R and GCGR for balanced simultaneous agonist action. The gene discussed is GCGR; the disease is obesity due to melanocortin 4 receptor deficiency.