GLP1R and obesity due to melanocortin 4 receptor deficiency: Based on these actions, multiple glucagon-like peptide-1 receptor (GLP-1R) agonists (GLP-1RAs) have been developed for the treatment of type 2 diabetes (T2D); three agents, liraglutide, semaglutide, and tirzepatide, have been approved for weight loss in people living with overweight and related complications or obesity [2,3].