Zepbound vs Mounjaro
Same active ingredient, different FDA approvals and coverage
Mounjaro
Dual GIP/GLP-1 receptor agonistZepbound
Dual GIP/GLP-1 receptor agonistHow They Work
Mounjaro
Dual GIP/GLP-1 receptor agonist. Same active ingredient as Zepbound.
Zepbound
Identical to Mounjaro (tirzepatide). FDA-approved specifically for weight loss.
Weight Loss Efficacy
SURPASS trials focused on A1C reduction, with significant weight loss as secondary outcome
SURMOUNT-1 trial: 20.9% weight loss at 15 mg dose vs 3.1% placebo, counting everyone who started (22.5% estimated assuming everyone stayed on treatment; 72 weeks, n=2,539)
These figures come from separate trials in different groups of people, with and without type 2 diabetes, so they are not a head-to-head comparison.
Side Effects
Mounjaro
- Nausea (18%)
- Diarrhea (17%)
- Decreased appetite (12%)
- Vomiting (6%)
- Constipation (7%)
Zepbound
- Nausea (33%)
- Diarrhea (25%)
- Vomiting (17%)
- Constipation (20%)
- Injection site reactions (7%)
Cost Comparison
| Cost type | Mounjaro | Zepbound |
|---|---|---|
| Without Insurance | MounjaroList price $1,112.16 per fill (Lilly, WAC January 1, 2026; one fill is a month, four pens). LillyDirect self-pay starts at $499 a month, at every dose | ZepboundList price $499 to $1,086.37 per fill by product and dose (Lilly, WAC January 1, 2026); LillyDirect self-pay from $299 for a 28-day supply, by dose |
| With Insurance | MounjaroDepends on your plan. For eligible patients whose commercial plan covers Mounjaro for type 2 diabetes, the Lilly savings card can lower the cost to as little as $25 for up to a 3-month fill; savings are capped at $150 per month of supply | ZepboundDepends on your plan. For eligible patients whose commercial plan covers the Zepbound single-dose pen, the Lilly savings card can lower the cost to as little as $25/month; savings are capped at $100/month |
| Compounded | MounjaroNot FDA-approved. Since the shortage ended, compounding pharmacies generally may not make copies of the brand drug. See the FDA note below the table. | ZepboundNot FDA-approved. Since the shortage ended, compounding pharmacies generally may not make copies of the brand drug. See the FDA note below the table. |
Compounded versions are not FDA-approved. Since the semaglutide and tirzepatide shortages ended, a state-licensed 503A pharmacy generally may not regularly make copies of these drugs. One exception applies when the prescriber determines that a change produces a significant difference for an identified individual patient; large 503B outsourcing facilities face separate, stricter limits. Source: FDA compounding policy statement, updated April 1, 2026.
Pros & Cons
Mounjaro
Advantages
- Strong insurance coverage for type 2 diabetes
- Same active ingredient as Zepbound
- Multiple dose options for fine-tuning
- Well-tolerated GI side effect profile
Considerations
- Not FDA-approved for weight loss
- Off-label weight loss use may not be covered
- Requires diabetes or related diagnosis for insurance coverage
- Newer drug with limited long-term data (since 2022)
Zepbound
Advantages
- FDA-approved specifically for weight loss
- Clinical trials designed for weight management outcomes
- Identical active ingredient to Mounjaro at same doses
- Some plans cover it for weight loss
Considerations
- Insurance coverage still limited for weight loss
- Higher out-of-pocket cost if not covered
- Newer approval (2023). Less prescribing history
- Side effect rates reported higher in weight loss trials
The Bottom Line
Mounjaro and Zepbound are the same drug (tirzepatide) made by Eli Lilly. If you have type 2 diabetes, Mounjaro offers better insurance coverage. If your primary goal is weight management without diabetes, Zepbound is the appropriate prescription. Your doctor and insurance plan will largely determine which you receive.
Frequently Asked Questions
Yes. Both contain tirzepatide made by Eli Lilly. The difference is FDA labeling: Mounjaro is approved for type 2 diabetes, Zepbound for chronic weight management. Same drug, same doses, different indication.
When the primary goal is weight loss (without type 2 diabetes), prescribing Zepbound aligns with the FDA-approved indication. This can also affect insurance coverage. Some plans cover Zepbound for weight loss but not off-label Mounjaro.
Lilly lists Mounjaro at $1,112.16 per fill, which it defines as a month of four pens, and Zepbound at $499 to $1,086.37 per fill depending on the product and dose. The real cost difference comes down to insurance. Mounjaro is more likely covered under diabetes benefits, while Zepbound coverage depends on whether your plan includes weight loss medications.
Yes, since they're the same drug, switching is seamless. Your doctor can match your current dose exactly. The main reason to switch is usually insurance-related.
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See allMedical Disclaimer: This comparison is for informational purposes only and is not medical advice. All clinical data is sourced from FDA prescribing information and published peer-reviewed trials. Individual results vary. Always consult a qualified healthcare provider before starting, stopping, or switching any medication.