Retatrutide (LY-3437943) is an experimental drug for obesity developed by the American pharmaceutical company Eli Lilly and Company. It is a triple glucagon hormone receptor agonist (GLP-1, GIP, and GCGR receptors).[1] It has been shown to achieve a more than 17.5% mean weight reduction in adults without diabetes but with obesity or preobesity (overweight) during a phase 2 trial.[2][3][4] In the trial, the participants who received the highest dose (12 mg) showed a mean weight reduction of 24.2% after 48 weeks.[4] Retatrutide is currently in phase 3 clinical trials, one of many GLP-1 receptor agonists in development.[5]