# Zepbound vs Mounjaro: the same molecule under two names

> Source: https://peptidewellnessusa.com/peptides/compare/zepbound-vs-mounjaro/
> Compare · GLP-1
> By PeptideWellness Editorial Team · Medically reviewed by Ksenia Petrushkina, PA-C, MPAS · Updated November 11, 2026 · 5 min read

Zepbound and Mounjaro are the same molecule, tirzepatide, from the same company, in the same strengths and the same devices. What differs is the approved use, and everything that follows from it: which trials sit behind each label, who prescribes which, and what insurance will pay for.

Zepbound and Mounjaro both contain tirzepatide. Same manufacturer, same strengths, same injection devices, same escalation schedule. A 10 mg dose of one delivers the same drug as a 10 mg dose of the other.

What differs is the label. Mounjaro is approved for type 2 diabetes; Zepbound is approved for weight and for obstructive sleep apnea with obesity [1][2]. From that single difference follow the trials behind each name, who is prescribed which, and what it costs.

## What is identical

Both are tirzepatide, a molecule that activates two gut-hormone receptors, GIP and GLP-1 [1][2]. Both are injected under the skin once a week, in the abdomen, thigh or, with another person's help, the back of the upper arm, rotating sites [1][2].

Both start at 2.5 mg a week for four weeks, a dose neither label treats as a maintenance dose, and rise in 2.5 mg steps no sooner than every four weeks. The maximum for both in adults is 15 mg a week [1][2]. A missed dose can be taken within four days; doses must be at least three days apart [1][2].

Both come in the same four presentations: a single-dose pen, a single-dose vial, a multi-dose vial and a KwikPen, with the last two holding four weekly doses [1][2].

Neither may be taken with the other, or with any other tirzepatide or GLP-1 product [1].

## What differs

|  | Zepbound | Mounjaro |
| --- | --- | --- |
| Approved for | Weight reduction and keeping it off in adults with obesity, or overweight with a weight-related condition; moderate to severe obstructive sleep apnea with obesity | Blood-sugar control in type 2 diabetes, in adults and children 10 and over; reducing major cardiovascular events in type 2 diabetes at high risk |
| Maintenance doses | 5, 10 or 15 mg; for sleep apnea, 10 or 15 mg | Any dose from 2.5 mg up as glycemic control requires |
| Maximum | 15 mg | 15 mg in adults, 10 mg in children |
| Children | Not studied | Approved from age 10 for type 2 diabetes |

Sources: the two labels [1][2].

The pediatric difference is real: Mounjaro was tested in children aged 10 and over with type 2 diabetes, where 5 and 10 mg lowered HbA1c by 1.9 and 2.2 percentage points against 0.2 on placebo over 30 weeks [2]. Zepbound has not been studied in children at all [1].

## The trials behind each name

The two programs measured different things, which is why the numbers quoted for "Zepbound" and "Mounjaro" look so different.

**Zepbound's trials measured weight.** Over 72 weeks in adults with obesity or overweight and no diabetes, average weight fell by 15.0% on 5 mg, 19.5% on 10 mg and 20.9% on 15 mg, against 3.1% on placebo. In adults who also had type 2 diabetes the figures were 12.8% and 14.7% on 10 and 15 mg, against 3.2% [1]. Two further trials in people with obesity and moderate to severe sleep apnea led to that second indication [1].

**Mounjaro's trials measured blood sugar.** The one most often quoted, SURPASS-2, compared it head to head with semaglutide 1 mg added to metformin over 40 weeks. HbA1c fell by 2.0, 2.2 and 2.3 percentage points on 5, 10 and 15 mg against 1.9 on semaglutide, and weight fell by 7.6, 9.3 and 11.2 kg against 5.7 kg [2]. That was semaglutide at the diabetes dose, not the 2.4 mg weight dose; our [tirzepatide vs semaglutide](https://peptidewellnessusa.com/peptides/compare/tirzepatide-vs-semaglutide/) page covers the weight comparison.

**The cardiovascular trial.** SURPASS-CVOT followed 13,299 adults with type 2 diabetes and established heart disease for a median of about four years, comparing tirzepatide with dulaglutide. Tirzepatide was non-inferior, with a hazard ratio of 0.92 for heart death, heart attack or stroke; superiority was not shown [2]. That result sits on the Mounjaro label, not Zepbound's.

## Side effects

The same molecule produces the same effects, though the trial populations differ. In the Zepbound weight trials nausea affected 25% to 29% of people against 8% on placebo, diarrhea 19% to 23%, vomiting 8% to 13%, and hair loss 4% to 5% against 1% [1]. In the Mounjaro diabetes trials nausea was 12% to 18% against 4%, diarrhea 12% to 17% against 9% [2].

Both labels carry the same boxed warning about thyroid C-cell tumors in rodents, and the same warnings for pancreatitis, gallbladder disease, kidney injury from dehydration, severe stomach problems, allergic reactions, low blood sugar, worsening diabetic eye disease and food entering the lungs under anesthesia [1][2]. Our [GLP-1 side effects](https://peptidewellnessusa.com/learn/glp-1-side-effects/) page sets out the numbers in full.

## Cost and coverage

This is where the two names matter most to a patient.

Insurance for Mounjaro follows diabetes coverage, which is common. Insurance for Zepbound follows weight coverage, which depends on the employer's plan, and sleep apnea coverage, which is newer.

Lilly sells Zepbound direct at $299 a month for the starting dose, $399 at 5 mg and $449 at 7.5 to 15 mg if you reorder within 45 days, with a month defined as 28 days [3]. The Medicare GLP-1 Bridge, which runs to the end of 2027, covers the Zepbound KwikPen for weight management at $50 a month, but not Zepbound prescribed for sleep apnea, and not Mounjaro [4].

Being prescribed Mounjaro for weight is off-label. It is legal for a prescriber to do, and it is the usual reason an insurer refuses to pay. [How to get a GLP-1](https://peptidewellnessusa.com/learn/how-to-get-a-glp-1/) goes through the routes.

## Which one

You do not choose between them; the diagnosis does. Type 2 diabetes points to Mounjaro, whose label carries the diabetes and heart-outcome data. Weight, or sleep apnea with obesity, points to Zepbound, whose label carries the weight and apnea data.

If you are taking one and your insurance stops covering it, the other is not a substitute to arrange yourself: it needs a prescription written for an approved use, and the dose ladder has to be followed from wherever you are.

## Frequently asked

### Is Zepbound the same as Mounjaro?

Same molecule, tirzepatide, same strengths and devices. Different approved uses: weight and sleep apnea for Zepbound, type 2 diabetes for Mounjaro [1][2].

### Can I switch from Mounjaro to Zepbound?

Only with a prescription written for an approved Zepbound use. The dose is the same at each step, so a prescriber can usually continue at the dose you are on.

### Which is cheaper?

It depends on coverage, not on the drug. Mounjaro is covered as a diabetes drug more often; Zepbound has a published self-pay price from Lilly of $299 to $449 a month depending on dose, and the Medicare Bridge at $50 for the KwikPen [3][4].

### Does Mounjaro work for weight loss?

It is the same molecule, and in its diabetes trials people lost 7.6 to 11.2 kg over 40 weeks [2]. Prescribed for weight it is off-label, which is why Zepbound exists.

### Is one stronger than the other?

No. Both reach 15 mg a week in adults [1][2].

## References

1. [FDA. Zepbound (tirzepatide) injection, prescribing information, effective 28 August 2026: sections 1, 2, 3, 5, 6.1 and 14. DailyMed, read 10 November 2026.](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=487cd7e7-434c-4925-99fa-aa80b1cc776b)
2. [FDA. Mounjaro (tirzepatide) injection, prescribing information, effective 27 August 2026: sections 1, 2, 3, 6.1 and 14. DailyMed, read 10 November 2026.](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d2d7da5d-ad07-4228-955f-cf7e355c8cc0)
3. [LillyDirect. Zepbound self-pay prices and refill conditions. CMAT-05333 10/2026. Read 10 November 2026.](https://www.lilly.com/lillydirect/zepbound)
4. [Medicare.gov. Weight loss drugs: the Medicare GLP-1 Bridge. Read 10 November 2026.](https://www.medicare.gov/coverage/weight-loss-drugs)

## Medical disclaimer

This page is informational and is not medical advice. It compares two approved labels for the same molecule; it cannot tell you whether tirzepatide is appropriate for you. Both products carry a boxed warning for thyroid C-cell tumors and are not for anyone with a personal or family history of medullary thyroid carcinoma or MEN 2. Which product, which dose and whether to start are decisions for a prescriber.