Mounjaro and Zepbound are both tirzepatide manufactured by Eli Lilly. Mounjaro is approved for type 2 diabetes; Zepbound is approved for chronic weight management and obstructive sleep apnea with obesity. The molecule is identical.
Mounjaro and Zepbound are both injectable tirzepatide manufactured by Eli Lilly. They are the same molecule. Mounjaro is FDA-approved for type 2 diabetes at doses of 2.5-15 mg weekly. Zepbound is FDA-approved for chronic weight management at the same dose range and, as of December 2024, for moderate-to-severe obstructive sleep apnea in adults with obesity. The trial evidence base is the SURPASS program for Mounjaro and SURMOUNT for Zepbound¹².
Identical molecule, different indication
Tirzepatide is a once-weekly dual GIP/GLP-1 receptor agonist with ~5-day half-life, manufactured by Eli Lilly. The active ingredient is identical across Mounjaro and Zepbound. The same six dose strengths are available in both: 2.5, 5, 7.5, 10, 12.5, and 15 mg pre-filled single-dose autoinjector pens¹².
Both share the boxed warning for thyroid C-cell tumors, warnings for pancreatitis, gallbladder disease, hypersensitivity, AKI (dehydration setting), and contraindications for personal or family history of medullary thyroid carcinoma or MEN2.
Indication comparison
Mounjaro is indicated for adults with T2D to improve glycemic control as adjunct to diet and exercise. As of 2026 it is not approved for CV outcome reduction in T2D, though SURPASS-CVOT data are awaited¹.
Zepbound is indicated for: (1) chronic weight management in adults with BMI ≥30 or ≥27 with weight-related comorbidity; (2) moderate-to-severe obstructive sleep apnea (OSA) in adults with obesity, added December 2024 after SURMOUNT-OSA²³.
Trial evidence base
Mounjaro approved on the SURPASS program (SURPASS-1 through SURPASS-5) comparing tirzepatide to placebo, semaglutide, insulin glargine, and insulin degludec. SURPASS-2 was a head-to-head against semaglutide 1.0 mg, with tirzepatide producing superior glycemic control and weight loss&sup4;.
Zepbound approved on the SURMOUNT program: SURMOUNT-1 (general obesity), SURMOUNT-2 (T2D + obesity), SURMOUNT-3 (intensive lifestyle), SURMOUNT-4 (continued vs withdrawal), SURMOUNT-OSA (sleep apnea).
OSA approval
In December 2024, FDA approved Zepbound for moderate-to-severe OSA in adults with obesity. SURMOUNT-OSA randomized 469 patients with OSA and obesity to tirzepatide or placebo for 52 weeks. Tirzepatide reduced AHI alongside weight loss, with ~43% of tirzepatide-treated no longer meeting OSA criteria at study end³. This is the first FDA approval of a weight-management medication specifically for a sleep-disordered breathing condition.
Clinical practice considerations
Mounjaro is generally covered for T2D. Off-label prescribing for weight loss in non-diabetic patients has been common but increasingly restricted. Zepbound coverage for chronic weight management has expanded since approval but remains less reliable than Mounjaro coverage for T2D.
Patients with T2D who also need weight management may use either; insurance coverage and pharmacy stocking often drive the choice. Molecule is identical so clinical effect is the same at equivalent doses.
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Yes. Both are tirzepatide manufactured by Eli Lilly. Mounjaro is approved for T2D. Zepbound is approved for chronic weight management and for OSA with obesity.
Can I use Mounjaro for weight loss instead of Zepbound?
Pharmacologically yes — molecule is identical. Regulatorily Mounjaro is approved for T2D not weight management. Prior authorization typically requires the matching indication.
Which is better for T2D?
Mounjaro is FDA-approved for T2D. Zepbound has not been independently studied as primary T2D medication, though SURMOUNT-2 demonstrated meaningful HbA1c reduction in T2D + obesity.
Does Zepbound treat sleep apnea?
Yes, as of December 2024. Approved for moderate-to-severe OSA in adults with obesity, based on SURMOUNT-OSA.
Side-effect profile different between Mounjaro and Zepbound?
No. Pharmacology is identical. Side-effect profile, contraindications, and warnings are the same.
References
U.S. Food and Drug Administration.Mounjaro (tirzepatide) injection — Prescribing Information.FDA Drug Approval Records. May 2022 (updated 2024).View source
U.S. Food and Drug Administration.Zepbound (tirzepatide) injection — Prescribing Information.FDA Drug Approval Records. November 2023 (updated 2024).View source
Malhotra A, Grunstein RR, Fietze I, et al.Tirzepatide for the Treatment of Obstructive Sleep Apnea and Obesity (SURMOUNT-OSA).N Engl J Med. 2024;391(13):1193-1205.PMID: 38912654
Frías JP, Davies MJ, Rosenstock J, et al.Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes (SURPASS-2).N Engl J Med. 2021;385(6):503-515.PMID: 34170647
Citations are peer-reviewed where available. PubMed (PMID) links resolve to NCBI's PubMed. FDA links resolve to fda.gov. All citations were last verified 2026-05-11.
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