What's the difference between GLP-1 and GIP?

Your gut releases several hormones after meals; two matter for weight-loss pharmacology: - GLP-1 (glucagon-like peptide-1): the appetite heavyweight. Signals fullness to the brain, slows stomach emptying, boosts glucose-dependent insulin, suppresses glucagon. - GIP (glucose-dependent insulinotropic polypeptide): historically considered the “other” incretin. It enhances insulin secretion and acts on fat tissue, influencing how adipose handles and stores energy. On its own it was a weight-loss disappointment. The surprise of the decade was that combining them beats either alone. Tirzepatide — a single molecule shaped to activate both receptors — produced up to 20.9% average weight loss in SURMOUNT-1, versus 14.9% for semaglutide in the comparable STEP 1 trial, and confirmed its edge head-to-head in SURMOUNT-5. The leading hypotheses: GIP co-activation amplifies satiety signaling in the brain while improving fat-tissue metabolism, and it may also blunt nausea, allowing higher tolerated dosing. The pipeline continues the theme: retatrutide adds a third receptor (glucagon, which raises energy expenditure) — see what is retatrutide.