Metabolic Research Comparison
Semaglutide vs Tirzepatide vs Retatrutide: Receptors and Published Evidence
Semaglutide, tirzepatide, and retatrutide represent three distinct receptor architectures: GLP-1; GLP-1 plus GIP; and GLP-1 plus GIP plus glucagon.
Reviewed · August 25, 2026
One, Two, and Three Receptor Systems
Semaglutide is a GLP-1 receptor agonist. Tirzepatide activates GIP and GLP-1 receptors. Retatrutide is investigational and was designed to activate GIP, GLP-1, and glucagon receptors in one molecule.
Do Not Treat Separate Trials as Head-to-Head
STEP 1, SURMOUNT-1, and retatrutide trials differ in population, duration, dose, protocol, and investigational status. Percent changes from separate studies can describe each program but cannot establish a direct winner without a controlled comparison.
What to Compare
A useful evidence review examines receptor activity, study population, duration, attrition, adverse events, body-composition endpoints, and regulatory status—not only the largest reported percentage.