Co-administration of amylin and an MC4R agonist to rats had a greater effect on weight loss and food intake than treatment with amylin alone (Roth et al. 2012), and amylin-induced stimulation of thermogenesis in iBAT was blocked by an MC4R antagonist (Li et al. 2019), indicating that combined treatment may be beneficial in obesity. Here, IAPP is linked to obesity due to melanocortin 4 receptor deficiency.