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Semaglutide vs tirzepatide: what's the difference?

Reviewed by the glpzoom Editorial Team against primary clinical sources — FDA labeling, peer-reviewed trials, and specialty-society guidelines.
Content current as of June 2026; updated when guidance or availability changes.
Semaglutide is a pure GLP-1 receptor agonist, mimicking the gut hormone GLP-1 to suppress appetite, slow gastric emptying, and improve insulin response. It's the active ingredient in Ozempic (T2D), Wegovy (weight loss), and Rybelsus (oral T2D). Tirzepatide adds activity at a second receptor — GIP (glucose-dependent insulinotropic polypeptide) — making it a dual agonist. The added GIP activity produces stronger appetite suppression and metabolic effects, translating to more weight loss in clinical trials. It's the active ingredient in Mounjaro (T2D) and Zepbound (weight loss). Both are once-weekly subcutaneous injections with similar titration schedules. Side-effect profiles are similar, though some patients tolerate one molecule better than the other. The dual-agonist mechanism of tirzepatide is also the foundation for newer drugs in development that add a third receptor (e.g., GLP-1 + GIP + glucagon).

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Drugs referenced

Related questions

  • How do GLP-1 drugs work?

    GLP-1 receptor agonists mimic glucagon-like peptide-1, a gut hormone released after eating. They work through three main pathways: (1) Slowing gastric emptying — food stays in the stomach longer, prolonging fullness. (2) Suppressing appetite in the brain — they reduce the constant 'food noise' many patients describe, making it easier to eat smaller portions

  • Wegovy vs Zepbound: which is more effective?

    In separate Phase 3 trials, Zepbound (tirzepatide 15mg) produced ~20% mean body weight loss vs Wegovy (semaglutide 2.4mg) at ~15%. A head-to-head trial (SURMOUNT-5) confirmed Zepbound's edge. That said, individual response varies widely: some patients lose more on semaglutide than tirzepatide, others tolerate one's side-effect profile better than the other.

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