Mounjaro vs Zepbound: What's the Difference?
Reviewed by Sydney Duong, RD, GLPeak Clinical Lead · Last updated 2026-06-17
Quick answer: Mounjaro and Zepbound are the same drug — tirzepatide, a dual GIP/GLP-1 agonist from Eli Lilly. Mounjaro is FDA-approved for type 2 diabetes; Zepbound is FDA-approved for chronic weight management. Both share the identical molecule, doses (2.5–15 mg weekly), pen device, and side-effect profile.
Same molecule, two labels
Tirzepatide is the active ingredient in both. Mounjaro launched in 2022 for type 2 diabetes. Zepbound launched in late 2023 specifically for weight management — a regulatory move that mirrors Novo Nordisk's Ozempic/Wegovy split.
Dose and titration
Identical titration ladder for both products. Patients move up every 4 weeks based on tolerability and prescriber judgment.
- 2.5 mg (starter, not maintenance)
- 5 mg → 7.5 mg → 10 mg → 12.5 mg → 15 mg (ceiling)
- Most patients respond well at 5–10 mg; the 15 mg ceiling is reserved for patients needing additional benefit.
Weight-loss outcomes
In SURMOUNT-1, the registrational trial for Zepbound, the 15 mg dose produced an average ~22.5% weight loss over 72 weeks. Mounjaro produced similar weight-loss outcomes in SURPASS trials of patients with diabetes, though glycemic effect was the primary endpoint.
Cost and coverage
Mounjaro is typically covered for type 2 diabetes. Zepbound coverage for obesity varies by plan. Eli Lilly offers self-pay vial options for Zepbound at lower prices than the pen (~$349–$499/month depending on dose) through LillyDirect.
Which one are you eligible for?
If you have type 2 diabetes, Mounjaro is the on-label option and most likely to be covered. If you don't have diabetes and meet BMI criteria (≥30, or ≥27 with a weight-related condition), Zepbound is on-label and may be accessible through LillyDirect even when not covered by insurance.
Frequently asked questions
Is Mounjaro the same as Zepbound?
Yes — both are tirzepatide, made by Eli Lilly. They share the same active ingredient, doses, pen device, and side-effect profile. The only differences are the FDA-approved indication (diabetes vs weight management) and the brand-specific insurance coverage rules.
Can I switch from Mounjaro to Zepbound?
Yes, with your prescriber's guidance. The dose-for-dose switch is usually straightforward because the drug is identical. The main reason patients switch is insurance — Zepbound is more likely to be covered for weight loss without a diabetes diagnosis.
Which loses more weight, Zepbound or Wegovy?
In head-to-head trial data (SURMOUNT-5), Zepbound 15 mg produced ~20.2% average weight loss vs ~13.7% on Wegovy 2.4 mg over 72 weeks. Tirzepatide's dual GIP/GLP-1 mechanism is thought to be the reason.
What is the cheapest way to get Zepbound?
Eli Lilly's LillyDirect self-pay vial program offers Zepbound at roughly $349 for the 2.5 mg starter dose and $499 for higher doses without insurance, as of 2026. Coverage and pricing change frequently — check LillyDirect for current rates.
References
Related GLPeak tools
Educational only — not medical advice. Consult your prescriber before changing any medication.