The physiological effects of GLP-1, which include decreasing blood glucose levels and promoting satiety [for review (Gribble and Reimann, 2021)], have led to the development of GLP-1 receptor (GLP-1R) agonists for managing type 2 diabetes and obesity [for review see (Andersen et al., 2018)]. Here, GLP1R is linked to obesity due to melanocortin 4 receptor deficiency.