Zepbound and Wegovy are the two brands most people mean when they talk about prescription weight-management injections. Zepbound is a brand of tirzepatide, a GLP-1 and GIP dual agonist, while Wegovy is a brand of semaglutide, a GLP-1 agonist. Both are FDA-approved specifically for chronic weight management, so this comparison keeps to their mechanism, dosing, and the trials behind each.
Reviewed for accuracy · Last reviewed July 7, 2026Both have Phase 3 evidence in their approved weight-management setting: tirzepatide in the SURMOUNT-1 trial and semaglutide in the STEP 1 trial. Those were separate trials with different designs and populations, so the honest position is that they are not a clean head-to-head, and cross-trial comparisons of weight change are not reliable as a ranking.
Mechanistically, Zepbound's tirzepatide adds the GIP receptor to the GLP-1 target that Wegovy's semaglutide uses. Both are once-weekly subcutaneous injections titrated up gradually, and both carry the same class boxed warning for thyroid C-cell tumors.
Which is appropriate is a medical decision that depends on tolerability, coexisting conditions, coverage, and access rather than molecule alone. Independently sourced vials of either carry no guarantee of the testing a regulated product does.
This page is an independent educational reference and is not medical advice. Talk to a doctor before starting or adjusting any compound.