How GLP-1 Peptides Work
Last updated July 2, 2026 · Medically reviewed by David Chen, MD, PhD
Your body already makes hormones that control appetite, blood sugar, and how you burn energy. Three of the most important are GLP-1 (glucagon-like peptide-1), GIP (glucose-dependent insulinotropic polypeptide), and glucagon. When you eat, these signals tell your brain you are full, help your pancreas release insulin, and influence how fat is stored or burned.
The compounds studied on this site are lab-engineered peptides designed to mimic or amplify those natural signals. Each one engages a different combination of receptors — which is exactly why they differ in how much weight loss they produce. Use the selector below to see the pathway for each compound.
More receptors, more effect
The pattern is straightforward: adding receptors generally stacks the effects. Semaglutide engages GLP-1 alone; tirzepatide adds GIP; and retatrutide adds glucagon on top of both. Read the full profile of each in its deep dive — semaglutide, tirzepatide, and retatrutide — or see them side by side.
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