Medications
Tirzepatide explained (Mounjaro and Zepbound)
What tirzepatide is, how it differs from semaglutide, and the brand names it is sold under.
5 min read · Updated 2026-05-24
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What tirzepatide is
Tirzepatide is a dual agonist: it activates both the GLP-1 and GIP receptors.
It was developed by Eli Lilly and approved by the FDA in 2022.
Brand names
Mounjaro — once-weekly injection approved for type 2 diabetes.
Zepbound — once-weekly injection approved for chronic weight management.
Both are the same molecule at different approved indications.
How it differs from semaglutide
Semaglutide is GLP-1 only. Tirzepatide is GLP-1 + GIP.
Head-to-head trials in type 2 diabetes have shown tirzepatide producing larger average reductions in A1C and body weight than semaglutide at the doses studied.
Side effect profile is broadly similar — primarily gastrointestinal — and is managed with the same slow-titration approach.
Where it fits
Tirzepatide sits between semaglutide (single agonist, longest track record) and retatrutide (triple agonist, still investigational) on the receptor-coverage spectrum.
It is the most recently approved GLP-1-class drug widely available by prescription.
Key takeaways
- Tirzepatide is a dual GLP-1 + GIP agonist.
- Sold as Mounjaro (diabetes) and Zepbound (weight management).
- Head-to-head trials show larger average effects than semaglutide; long-term real-world data is still accumulating.
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