Mounjaro vs Zepbound
Last reviewed against the current FDA prescribing information for both products. Not medical advice.
Short answer
Mounjaro and Zepbound are the same medicine, tirzepatide, made by Eli Lilly in the same dose strengths (2.5 mg to 15 mg) and the same kinds of pens and vials. The difference is what each is FDA-approved for.
Mounjaro is approved for type 2 diabetes in adults and children 10 and older, and to lower cardiovascular risk in adults with type 2 diabetes at high risk. Zepbound is approved for long-term weight management in adults with obesity, or overweight with a weight-related condition, and for moderate to severe obstructive sleep apnea in adults with obesity.
Zepbound’s label says using it with other tirzepatide-containing products (such as Mounjaro) or any GLP-1 receptor agonist is not recommended. Which one you are prescribed depends on your diagnosis; ask your prescriber which fits your situation.
Key differences
- Approved use: type 2 diabetes and cardiovascular risk reduction (Mounjaro) vs weight management and sleep apnea (Zepbound).
- Age: Mounjaro is approved from age 10 for type 2 diabetes; Zepbound is approved for adults.
- Dosing: both start at 2.5 mg weekly and go up in 2.5 mg steps to a 15 mg maximum (10 mg maximum for children on Mounjaro).
- Devices and storage: the same presentations (single-dose pens and vials, 4-dose vials and KwikPens) and the same storage rules.
- Weight results: only Zepbound’s label reports weight-management trial results.
Mounjaro and Zepbound side by side
| From the FDA label | Mounjaro | Zepbound |
|---|---|---|
| Active ingredient | tirzepatide | tirzepatide |
| Drug class | GIP receptor and GLP-1 receptor agonist | GIP receptor and GLP-1 receptor agonist |
| Manufacturer | Eli Lilly | Eli Lilly |
| FDA-approved uses |
|
|
| Approved for weight management? | No | Yes |
| How it's taken | Injection under the skin (subcutaneous) | Injection under the skin (subcutaneous) |
| How often | Once weekly | Once weekly |
| Starting dose | 2.5 mg once weekly | 2.5 mg once weekly for 4 weeks (a starter dose, not a maintenance dose) |
| Dose increases | If more blood sugar control is needed, increase in 2.5 mg steps after at least 4 weeks on the current dose | Then 5 mg once weekly; can increase in 2.5 mg steps after at least 4 weeks on the current dose |
| Maintenance dose | No single maintenance dose in the label; the dose is raised in 2.5 mg steps only if more blood sugar control is needed | 5 mg, 10 mg or 15 mg once weekly for weight reduction; 10 mg or 15 mg for sleep apnea |
| Maximum dose | 15 mg once weekly in adults; 10 mg once weekly in children | 15 mg once weekly |
| When to take it | Any time of day, with or without meals. The injection day can be changed if doses are at least 3 days (72 hours) apart | Any time of day, with or without meals. The injection day can be changed if doses are at least 3 days (72 hours) apart |
| Pens and devices | Single-dose pens, single-dose vials, 4-dose vials and 4-dose KwikPens, each in 2.5, 5, 7.5, 10, 12.5 and 15 mg strengths | Single-dose pens, single-dose vials, 4-dose vials and 4-dose KwikPens, each in 2.5, 5, 7.5, 10, 12.5 and 15 mg strengths |
| Storage | Refrigerate. Single-dose pens and vials can be kept unrefrigerated (up to 86°F) for a total of 21 days. KwikPens and multi-dose vials: throw away after 30 days at room temperature, 30 days after first use or 4 weekly doses, whichever comes first. Do not freeze | Refrigerate. Single-dose pens and vials can be kept unrefrigerated (up to 86°F) for a total of 21 days. KwikPens and multi-dose vials: throw away after 30 days at room temperature, 30 days after first use or 4 weekly doses, whichever comes first. Do not freeze |
| Weight results in the label | None: not a weight-management product | In the label’s 72-week trial in adults with obesity, or overweight with a weight-related condition, without type 2 diabetes (Study 1), average weight change was −15.0% (5 mg), −19.5% (10 mg) and −20.9% (15 mg) with Zepbound vs −3.1% with placebo, on top of diet and exercise. (Zepbound label, section 14, Table 2) |
| Most common side effects (≥5%) | Nausea, Diarrhea, Decreased appetite, Vomiting, Constipation, Indigestion (dyspepsia), Abdominal pain | Nausea, Diarrhea, Vomiting, Constipation, Abdominal pain, Indigestion (dyspepsia), Injection site reactions, Fatigue, Hypersensitivity (allergic) reactions, Belching, Hair loss, Acid reflux (GERD) |
| Boxed warning | Risk of thyroid C-cell tumors. Do not use if you or a family member have had medullary thyroid carcinoma (MTC) or if you have Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). | Risk of thyroid C-cell tumors. Do not use if you or a family member have had medullary thyroid carcinoma (MTC) or if you have Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). |
| First FDA approval | May 13, 2022 | November 8, 2023 |
Side effects listed are the label's “most common adverse reactions”; the full label also covers serious risks such as pancreatitis, gallbladder problems and low blood sugar. Weight results come from separate placebo-controlled trials and are not a head-to-head comparison unless stated.
Good to know
- Mounjaro is not FDA-approved for weight management. The weight-management tirzepatide product is Zepbound.
Questions to ask your prescriber
- Which of these is approved for my diagnosis, and is it covered by my plan?
- How should I step up the dose, and what should I do if the side effects are hard to tolerate?
- Do any of my other medicines, or my personal or family history, rule one of these out?
- If I switch from one to the other, what dose should I start on and when?
Sources
- Mounjaro (tirzepatide) injection — FDA prescribing information, DailyMed (label effective August 27, 2026, version 40) (Sections 1, 2, 3, 6, 12.1, 16, boxed warning; checked September 24, 2026)
- Drugs@FDA: NDA 215866 (Mounjaro) (Original approval date; checked September 24, 2026)
- Zepbound (tirzepatide) injection — FDA prescribing information, DailyMed (label effective August 28, 2026, version 40) (Sections 1, 2, 3, 6, 12.1, 14, 16, boxed warning; checked September 24, 2026)
- Drugs@FDA: NDA 217806 (Zepbound) (Original approval date; checked September 24, 2026)
How we review: every fact on this page is taken from the current FDA prescribing information on DailyMed or from Drugs@FDA, and re-checked on the date shown. This page was reviewed against FDA labeling, not by a named clinician.
Medical disclaimer: This page is general information, not medical advice, diagnosis or treatment, and it doesn't cover every use, dose, warning or side effect. Always follow the advice of your doctor, pharmacist or other prescriber and read the Medication Guide that comes with your medicine. If you think you are having a medical emergency, call your local emergency number. ShotWise is a tracking app and does not prescribe, sell or recommend any medication.
