The GLP-1 receptor is just one of a range of G protein-coupled receptors (GPCRs) that enable drugs to target tissues of relevance for type 2 diabetes and obesity, and ligands to other GPCRs, including free fatty acid receptor 1 (FFAR1, also known as GPR40), GPR119 and the glucose-dependent insulinotropic polypeptide (GIP) receptor, have progressed recently through to clinical trials in humans (for examples, see [2, 3]). This evidence concerns the gene FFAR1 and obesity due to melanocortin 4 receptor deficiency.