Due to the rapid degradation of endogenous PYY and GLP-1, and the difficulties in administration of peptide-based drugs, exploiting the mechanisms that lead to their continued release, such as the GLP-1 receptor agonist, Saxenda, might be a useful alternative approach to treating patients suffering from obesity and impaired glucose tolerance. Here, GCG is linked to obesity due to melanocortin 4 receptor deficiency.