Management of metabolic diseases, such as obesity and type 2 diabetes, typically requires pharmacotherapeutics in addition to lifestyle changes. Several glucagon-like peptide-1 receptor (GLP-1R) agonists have acquired US FDA approval for treatment of these diseases, based on efficacy in glycaemic control and weight management in randomised controlled trials (RCTs). Recently, poly-agonist drugs that target GLP-1R and other metabolic signalling pathways, such as glucose-dependent insulinotropic receptors and glucagon receptors, have shown superior glycaemic control and weight loss effects compared with mono-agonist drugs in RCTs. This highlights the potential benefit of activating multiple gut hormone signalling pathways to achieve improved outcomes in the pharmacological treatment of metabolic diseases.