Drugmakers are pursuing medicines based on orexins, peptides involved in the biological system that keeps people awake, for a range of brain-related ailments. The interest follows the success of drugs based on glucagon-like peptide-1, or GLP-1, a hormone released by the gut after meals. GLP-1 drugs were initially developed to treat diabetes and later proved effective at helping people lose weight. They have also shown benefits in heart disease, kidney disease, sleep apnoea and other conditions. Pharmaceutical companies are betting that orexin-based medicines could achieve similarly broad therapeutic use in disorders affecting the brain.