retatrutide, a synthetic triple-agonist peptide that activates GLP-1, GIP, and glucagon receptors.lilly+2 What it is Retatrutide is described as a 39-amino-acid peptide used in research on metabolic regulation, glucose homeostasis, appetite, and energy balance.lilly+2 The “50” usually appears to be a product-size label, not a separate peptide name.nationwidepeptides+2 How it works By activating GLP-1 and GIP signaling, it helps regulate insulin and appetite, while glucagon receptor activity adds an energy-expenditure component.goodrx+2youtube That triple action is why it is being studied for obesity and broader metabolic effects.