Mounjaro vs Zepbound: Same Drug, Different Labels

Written by Nataliia Bondarchuk. Updated October 22, 2026.

Mounjaro and Zepbound are the same medicine. Both are tirzepatide, made by Eli Lilly, given as a once-weekly injection in the same doses from 2.5 mg to 15 mg. The difference is the label: Mounjaro is approved for type 2 diabetes, while Zepbound is approved for chronic weight management and obstructive sleep apnea in adults with obesity. That label decides who can be prescribed which brand, how insurance covers it, and what it costs.

Yes, chemically. Both contain tirzepatide, a once-weekly drug that activates two gut-hormone receptors, GIP and GLP-1. It slows stomach emptying, lowers blood sugar after meals and reduces appetite. The dose schedule is identical: 2.5 mg for four weeks, then increases of 2.5 mg at least every four weeks to a maintenance dose of 5 to 15 mg. See our tirzepatide dosage guide.

Zepbound's approval rests on the SURMOUNT trials in people with obesity without diabetes. In SURMOUNT-1, the 15 mg dose produced about 20.9% average weight loss over 72 weeks. Mounjaro's approval rests on the SURPASS trials in type 2 diabetes, where weight loss was smaller, typically about 7 to 12 kg, because people with diabetes tend to lose less on any GLP-1 drug. The drug is the same; the populations were different. For the realistic timeline, see tirzepatide weight loss by week.

Coverage depends on the label. Mounjaro is on most formularies for type 2 diabetes. Zepbound is covered for weight loss only if your plan includes obesity drugs. Without coverage, Lilly sells Zepbound directly through LillyDirect: $299 a month for 2.5 mg, $399 for 5 mg, and $449 for 7.5 mg to 15 mg if you refill within 45 days, in vials or the KwikPen. Medicare's GLP-1 Bridge, which started on July 1, 2026, offers certain GLP-1 drugs for weight loss at a $50 copay to eligible Part D members.

Because the drug is the same, so are the side effects: nausea, diarrhea, vomiting, constipation and reduced appetite, mainly after starting and after each dose increase. Both carry the same warnings about pancreatitis, gallbladder problems and a boxed warning about thyroid C-cell tumors seen in rodents. Our side effects guide and best foods to eat on tirzepatide cover how to manage them.

Yes. Because the dose strengths match, people who switch, for example after an insurance change, usually stay on the same dose. Your prescriber needs to write a new prescription for the other brand.

Because both brands contain tirzepatide, a generic would replace both; the patent timeline is in generic Zepbound and Mounjaro.

If you are also weighing an older daily injection, see liraglutide vs tirzepatide for how Saxenda and Victoza compare with Zepbound and Mounjaro.

One difference between the two brands is the sleep apnea indication, which belongs to Zepbound. See Zepbound for sleep apnea: what the approval covers for the trial results and coverage details.

Mounjaro and Zepbound are the same tirzepatide in the same doses. Mounjaro is the diabetes brand, Zepbound the weight-loss and sleep-apnea brand, and that label drives coverage and price. For how tirzepatide compares with other options, read tirzepatide vs semaglutide.