Mounjaro vs Zepbound: the same drug, two brands
Mounjaro and Zepbound are both tirzepatide, made by Eli Lilly and injected once a week at the same doses. Mounjaro is approved for type 2 diabetes and Zepbound for weight management and sleep apnea in obesity, which decides how each is covered and how you can buy it.
Updated October 15, 2026
At a glance
- Approved for
- Mounjaro
- Type 2 diabetes
- Zepbound
- Chronic weight management, and moderate to severe obstructive sleep apnea in adults with obesity
- Doses
- Mounjaro
- 2.5 mg rising to as much as 15 mg once a week
- Zepbound
- The same dose steps
- Forms
- Mounjaro
- Weekly pens
- Zepbound
- Weekly pens, and single-dose vials sold through LillyDirect
- Who pays
- Mounjaro
- Insurance may cover it for type 2 diabetes; check your plan
- Zepbound
- Varies by plan and by the use it is prescribed for; self-pay is another route
Mounjaro tirzepatide for type 2 diabetes | Zepbound tirzepatide for weight management and sleep apnea | |
|---|---|---|
| Approved for | Type 2 diabetes | Chronic weight management, and moderate to severe obstructive sleep apnea in adults with obesity |
| Doses | 2.5 mg rising to as much as 15 mg once a week | The same dose steps |
| Forms | Weekly pens | Weekly pens, and single-dose vials sold through LillyDirect |
| Who pays | Insurance may cover it for type 2 diabetes; check your plan | Varies by plan and by the use it is prescribed for; self-pay is another route |
Same medicine, different label
The molecule and dose steps are identical; what differs is the approved use printed on the label, and therefore what a pharmacy can bill to a plan. A prescriber writes the brand that matches the diagnosis. Using Mounjaro for weight loss alone is an off-label use, meaning it is not FDA-approved; a prescriber may decide it is appropriate, but a plan can limit coverage to the approved diabetes use.
Cost and coverage
Neither is generic. Lilly sells Zepbound directly to self-paying patients through LillyDirect, as vials and pens priced by dose, so compare that with any pharmacy quote for either brand. Because sleep apnea is a medical condition rather than weight loss alone, a plan, including a Medicare Part D plan, can cover Zepbound for that use. Eligible Medicare enrollees can also get the Zepbound pen through the Medicare GLP-1 bridge program until the end of 2027.
Side effects
Identical, because the drug is identical: mainly nausea, diarrhea, vomiting and constipation while the dose rises, with the same thyroid boxed warning and the same pancreatitis and gallbladder cautions as the GLP-1 drugs. Tirzepatide can also make oral birth control less reliable for a few weeks after starting and after each dose increase, so a backup method is advised then.
Questions for your prescriber
- Which brand matches my diagnosis?
- Would my plan cover Zepbound for sleep apnea?
- Is the vial or the pen better for me if I pay myself?
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Sources
- DailyMed, FDA-approved prescribing information
- MedlinePlus drug information (National Library of Medicine)
- LillyDirect
- CMS, Medicare GLP-1 Bridge
Written by the Script Unlock editorial team from the sources above. It is general information, not advice for you or your pet; your prescriber decides which medicine is right.
Script Unlock is a marketplace that lets licensed pharmacies quote a cash price on your prescription. It does not prescribe, dispense or sell medication, does not process patient payments, and does not give medical advice. Always follow the instructions of your prescriber and pharmacist and read the medication guide supplied with your medicine.