Peptide LibraryMounjaro vs Zepbound
Mounjaro and Zepbound both contain tirzepatide and are both made by Eli Lilly, with the same strengths (2.5 to 15 mg weekly) and devices. They are separate FDA-approved products: Mounjaro is approved for type 2 diabetes in adults and children 10 and older and for cardiovascular risk reduction in adults with type 2 diabetes; Zepbound is approved for weight management in adults and for moderate to severe obstructive sleep apnea in adults with obesity. Their supporting trials are different (SURPASS vs SURMOUNT).
Checked against the FDA label and cited trials on
Peptide Library is an independent educational resource. It is not affiliated with, sponsored or endorsed by Novo Nordisk or Eli Lilly; Ozempic, Wegovy, Mounjaro and Zepbound are trademarks of their owners and are named only to identify the products. This page summarizes FDA-approved prescribing information and published trials. It is not individual medical advice: dosing and any change to it are decided with a prescriber.
The products
Mounjaro (tirzepatide)
- Manufacturer
- Eli Lilly
- Form
- Once-weekly injection: single-dose pens or vials (2.5 to 15 mg), multi-dose KwikPen or vial
- FDA-approved uses
- Glycemic control in adults and children 10 and older with type 2 diabetes, with diet and exercise
- Reducing the risk of major cardiovascular events in adults with type 2 diabetes at high risk of them
- Boxed warning
- Risk of thyroid C-cell tumors: tirzepatide caused thyroid C-cell tumors in rats; whether it does in humans is unknown. Contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2.
Zepbound (tirzepatide)
- Manufacturer
- Eli Lilly
- Form
- Once-weekly injection: single-dose pens or vials (2.5 to 15 mg), multi-dose KwikPen or vial
- FDA-approved uses
- Reducing excess body weight and keeping it off long term in adults with obesity, or overweight with a weight-related condition
- Moderate to severe obstructive sleep apnea in adults with obesity
- Boxed warning
- Risk of thyroid C-cell tumors: tirzepatide caused thyroid C-cell tumors in rats; whether it does in humans is unknown. Contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2.
Side by side, from the labels
| Mounjaro | Zepbound | |
|---|---|---|
| Active ingredient | Tirzepatide (GIP and GLP-1 receptor agonist) | Tirzepatide (GIP and GLP-1 receptor agonist) |
| Approved for weight management | No | Yes (adults) |
| Type 2 diabetes glycemic control | Yes (adults and children 10+) | No |
| Other indications | Cardiovascular risk reduction in adults with type 2 diabetes at high risk (added 08/2026) | Moderate to severe obstructive sleep apnea in adults with obesity (approved 2024-12-20) |
| Labelled start | 2.5 mg weekly | 2.5 mg weekly for 4 weeks (for starting treatment only) |
| Maintenance | Increases of 2.5 mg after at least 4 weeks, as needed for glycemic control | 5, 10 or 15 mg for weight; 10 or 15 mg for sleep apnea |
| Maximum | 15 mg weekly (10 mg in children) | 15 mg weekly |
| Forms | Single-dose pens or vials, multi-dose KwikPen or vial | Single-dose pens or vials, multi-dose KwikPen or vial |
| Key trials | SURPASS-1 to -5, SURPASS-CVOT | SURMOUNT-1 to -4, SURMOUNT-OSA |
| Boxed warning | Thyroid C-cell tumors | Thyroid C-cell tumors |
Sources: the current prescribing information for each product, linked above.
Same molecule, different approvals
Mounjaro was approved in 2022 on the SURPASS diabetes trials; Zepbound in 2023 on the SURMOUNT weight trials, adding sleep apnea in December 2024. They are separate applications (NDA 215866 and NDA 217806) with no therapeutic-equivalence code between them, and each label covers only its own uses.
The Zepbound label says using it with other tirzepatide-containing products or any GLP-1 receptor agonist is not recommended.
What each label reports
Mounjaro’s label reports weight in kilograms as a secondary result of diabetes trials: in SURPASS-2 (40 weeks, vs semaglutide 1 mg) weight changed −7.6, −9.3 and −11.2 kg with 5, 10 and 15 mg vs −5.7 kg. In SURPASS-CVOT (13,299 adults with type 2 diabetes and cardiovascular disease), the hazard ratio for major cardiovascular events vs dulaglutide was 0.92 (95.3% CI 0.83 to 1.01): noninferior, superiority not established.
Zepbound’s label reports percent change as the primary outcome in people with obesity or overweight: −15.0%, −19.5% and −20.9% vs −3.1% in SURMOUNT-1. See the Zepbound weight loss chart.
Side effects
The common adverse reactions are gastrointestinal in both labels. Mounjaro (adults, placebo / 5 / 10 / 15 mg): nausea 4 / 12 / 15 / 18%, diarrhea 9 / 12 / 13 / 17%. Zepbound (placebo / 5 / 10 / 15 mg): nausea 8 / 25 / 29 / 28%, diarrhea 8 / 19 / 21 / 23%. The trial populations differ, so the rates are not compared with each other.
Questions
Are Mounjaro and Zepbound the same?
They contain the same active ingredient, tirzepatide, in the same strengths, but they are separate FDA-approved products with different indications and supporting trials.
Is Mounjaro approved for weight loss?
No. Mounjaro is approved for type 2 diabetes and cardiovascular risk reduction in type 2 diabetes. Zepbound is the tirzepatide product approved for weight management.
Do Mounjaro and Zepbound have the same doses?
Both come in 2.5 to 15 mg strengths with a 15 mg adult maximum, but each label sets its own schedule for its own indications, and Mounjaro’s pediatric maximum is 10 mg.