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Tirzepatide

Tirzepatide is Eli Lilly's once-weekly dual GIP/GLP-1 receptor agonist, sold as Mounjaro (type 2 diabetes) and Zepbound (weight management and obstructive sleep apnea). This entry covers its history, what it's approved and being studied for, and which brand name goes with which use.

Updated Sep 26, 2026Evidence-backed

Tirzepatide is a once-weekly injectable and the first of a class of "dual agonists": it activates two gut-hormone receptors, GIP and GLP-1, where older drugs in the class activate GLP-1 alone. Eli Lilly makes it and sells it under two brand names, depending on what it's prescribed for.

The different product names

In the U.S., Mounjaro is the brand approved for type 2 diabetes, and Zepbound is the brand approved for weight management and, more recently, obstructive sleep apnea. Tirzepatide is the generic (drug) name shared by both. Same molecule, different box. Outside the U.S., some markets use the Mounjaro brand for both diabetes and weight management, and the Zepbound name may not appear at all.

Timeline

  • May 2022: the FDA approves Mounjaro for type 2 diabetes in adults, the first dual GIP/GLP-1 agonist to reach the market (Eli Lilly (external link)). Its diabetes trials ran under the SURPASS program.
  • 2022: SURMOUNT-1, the pivotal trial of the SURMOUNT obesity program, is published. Average weight loss at the highest dose was roughly 20% (Jastreboff et al., New England Journal of Medicine, 2022, DOI (external link)).
  • November 8, 2023: the FDA approves Zepbound for chronic weight management.
  • December 20, 2024: the FDA approves Zepbound for moderate-to-severe obstructive sleep apnea in adults with obesity, the first medication ever approved for OSA.
  • December 2025: the FDA extends Mounjaro to children aged 10 and older with type 2 diabetes, based on the SURPASS-PEDS trial.
  • August 28, 2026: the FDA approves Mounjaro to reduce the risk of major adverse cardiovascular events in adults with type 2 diabetes, based on the SURPASS-CVOT trial.

What it's currently approved for (U.S.)

Mounjaro is approved to improve blood sugar control in type 2 diabetes, alongside diet and exercise, in adults and in children aged 10 and older. Since August 2026 it has also been approved to lower the risk of cardiovascular death, heart attack, or stroke in adults with type 2 diabetes at high cardiovascular risk.

Zepbound is approved for chronic weight management in adults with obesity, or overweight plus at least one weight-related condition, together with a reduced-calorie diet and more physical activity. It is also approved for moderate-to-severe obstructive sleep apnea in adults with obesity. The current labels have the details: Mounjaro (external link) and Zepbound (external link).

What it's being studied for (not yet approved)

Tirzepatide is in trials for several other conditions. As of September 2026, none of these are FDA-approved uses:

  • heart failure with preserved ejection fraction (the SUMMIT trial)
  • metabolic liver disease, MASH/NASH (the SYNERGY-NASH trial)
  • cardiovascular risk reduction in people without diabetes. The August 2026 cardiovascular indication covers Mounjaro in type 2 diabetes only, and semaglutide (Wegovy) remains the only GLP-1 with a cardiovascular indication in obesity without diabetes.
  • chronic kidney disease and other obesity-related conditions

Approvals expand over time, and investigational uses may or may not pan out. For what applies to your situation, your prescriber is the source of truth.

This is general education, not medical advice.

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Common questions

Questions people often ask about this topic.

  • What's the difference between Mounjaro and Zepbound?

    They're the same medication, tirzepatide, under two brand names. Mounjaro is approved for type 2 diabetes (and, since August 2026, for cardiovascular risk reduction in type 2 diabetes). Zepbound is approved for weight management and obstructive sleep apnea. In some countries outside the U.S., Mounjaro is used for both diabetes and weight management.

  • What is tirzepatide approved to treat?

    In the U.S.: type 2 diabetes (Mounjaro, in adults and children 10+), cardiovascular risk reduction in adults with type 2 diabetes (Mounjaro, approved August 2026), chronic weight management (Zepbound, for obesity or overweight with a related condition), and moderate-to-severe obstructive sleep apnea in adults with obesity (Zepbound).

  • How is tirzepatide different from semaglutide?

    Tirzepatide is a 'dual agonist': it activates two gut-hormone receptors, GIP and GLP-1, while semaglutide targets only GLP-1. On average it produces more weight loss. In the head-to-head SURMOUNT-5 trial, adults with obesity lost 20.2% of their body weight at 72 weeks on tirzepatide, compared with 13.7% on semaglutide.

  • Is tirzepatide approved for heart disease or fatty liver?

    Partly. As of August 2026, Mounjaro is approved to reduce the risk of major cardiovascular events in adults with type 2 diabetes, based on the SURPASS-CVOT trial. It is not approved for cardiovascular risk reduction in people without diabetes, or for heart failure or metabolic liver disease (MASH); those are still being studied. Your prescriber is the source of truth.

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