Comparisons
Mounjaro vs Zepbound: one molecule, two FDA labels
- 14 sources
- No vendors
Short answer
Mounjaro and Zepbound are both Eli Lilly's tirzepatide, in the same six strengths with a 2.5 mg start. Per the FDA labels as of Oct 21, 2026, Mounjaro is for type 2 diabetes; Zepbound is for chronic weight management and sleep apnea with obesity. Example: at 4 weeks per step, either adult ladder reaches 15 mg in week 21.
On this page11 sections
- Side-by-side comparison table
- Indications and approval dates
- The shared dose ladder
- Pens, vials and strengths
- Storage, missed doses and timing
- Half-life and how long it stays in the body
- Key trials behind each label
- Switching or taking them together
- Coverage and savings programs, compared without prices
- FAQ
- Sources
| Item | Value | Source |
|---|---|---|
| Active ingredient (both brands) | Tirzepatide, a GIP and GLP-1 receptor agonist made by Eli Lilly | DailyMed, Aug 27, 2026 |
| Mounjaro indications | Glycemic control in type 2 diabetes (adults and children 10 and older); lowering major cardiovascular event risk in adults with type 2 diabetes at high risk | DailyMed, Aug 27, 2026 |
| Zepbound indications | Chronic weight management in adults; moderate to severe obstructive sleep apnea in adults with obesity | DailyMed, Aug 28, 2026 |
| Mounjaro first approval | May 13, 2022 (type 2 diabetes) | Eli Lilly, May 13, 2022 |
| Zepbound approvals | Nov 8, 2023 (weight); Dec 20, 2024 (sleep apnea) | FDA, Nov 8, 2023 |
| Shared dose ladder | 2.5, 5, 7.5, 10, 12.5, 15 mg once weekly; at least 4 weeks per step | DailyMed, Aug 28, 2026 |
| Named maintenance doses | Zepbound: 5, 10 or 15 mg (10 or 15 mg for sleep apnea); Mounjaro: none named | DailyMed, Aug 27, 2026 |
| Maximum dose | 15 mg weekly for both in adults; 10 mg for Mounjaro in children 10 and older | DailyMed, Aug 27, 2026 |
| Presentations in both labels | Single-dose pen, single-dose vial, multi-dose vial, single-patient-use KwikPen | DailyMed, Aug 28, 2026 |
| Missed dose (both labels) | Take within 4 days (96 hours); otherwise skip | DailyMed, Aug 27, 2026 |
| Single-dose pen or vial out of the fridge | Up to 21 days total, not above 30 °C (86 °F), both brands | DailyMed, Aug 28, 2026 |
| Elimination half-life | About 5 days (Mounjaro label); about 5 to 6 days (Zepbound label) | DailyMed, Aug 28, 2026 |
| Using both together | Zepbound label: coadministration with other tirzepatide-containing products is not recommended | DailyMed, Aug 28, 2026 |
| SURMOUNT-1, week 72 | −20.9% at 15 mg vs −3.1% placebo (treatment-regimen estimand) | N Engl J Med, Jul 21, 2022 |
| SURPASS-2, week 40 | HbA1c −2.3 points at 15 mg vs −1.9 with semaglutide 1 mg (label, modified intent-to-treat) | DailyMed, Aug 27, 2026 |
Also useful: Tirzepatide level plotter, Tirzepatide mg to units.
Mounjaro and Zepbound are two brand names for one molecule, tirzepatide, made by Eli Lilly. They carry separate FDA labels for different conditions, so the purpose, the dose target and the savings programs differ. Everything below comes from the current prescribing information on DailyMed (Mounjaro effective Aug 27, 2026; Zepbound effective Aug 28, 2026) and the trial reports those labels rely on. For background on the drug itself, see the tirzepatide hub.
Side-by-side comparison table
| Item | Mounjaro | Zepbound |
|---|---|---|
| Active ingredient | Tirzepatide (GIP and GLP-1 receptor agonist) | Tirzepatide (GIP and GLP-1 receptor agonist) |
| Labeled for | Type 2 diabetes; cardiovascular risk in type 2 diabetes | Chronic weight management; sleep apnea with obesity |
| Ages covered | Adults and children 10 and older | Adults |
| First FDA approval | May 13, 2022 | Nov 8, 2023 |
| Starting dose | 2.5 mg once weekly | 2.5 mg once weekly for 4 weeks |
| Step size and pace | +2.5 mg after at least 4 weeks, if more glycemic control is needed | +2.5 mg after at least 4 weeks |
| Named maintenance doses | None | 5, 10 or 15 mg (weight); 10 or 15 mg (sleep apnea) |
| Maximum | 15 mg (adults); 10 mg (children) | 15 mg |
| Half-life in the label | About 5 days | About 5 to 6 days |
Sources: Mounjaro label (DailyMed, Aug 27, 2026), Zepbound label (DailyMed, Aug 28, 2026), Mounjaro approval (Eli Lilly, May 13, 2022), Zepbound approval (FDA, Nov 8, 2023).
Indications and approval dates
| Use | Mounjaro | Zepbound |
|---|---|---|
| Glycemic control in type 2 diabetes, with diet and exercise | Yes, adults and children 10 and older | No |
| Lower risk of cardiovascular death, heart attack or stroke in adults with type 2 diabetes at high risk | Yes | No |
| Weight reduction and long-term maintenance in adults with obesity, or overweight with at least one weight-related condition | No | Yes (approved Nov 8, 2023) |
| Moderate to severe obstructive sleep apnea in adults with obesity | No | Yes (approved Dec 20, 2024) |
Sources: (DailyMed, Aug 27, 2026) (DailyMed, Aug 28, 2026) (FDA, Nov 8, 2023) (FDA, Dec 20, 2024)
Mounjaro came first. FDA approved it for adults with type 2 diabetes on May 13, 2022, and Lilly’s release that day stated it is “not indicated for weight loss” (Eli Lilly, May 13, 2022). The label has since grown. Its Recent Major Changes list marks the pediatric indication as revised in 12/2025 and the cardiovascular indication in 08/2026 (DailyMed, Aug 27, 2026).
Zepbound followed as the weight-management brand on Nov 8, 2023, and on Dec 20, 2024 became the first medicine approved to treat moderate to severe obstructive sleep apnea, in adults with obesity (FDA, Nov 8, 2023) (FDA, Dec 20, 2024). The Zepbound Medication Guide says it is not known whether Zepbound is safe and effective in children (DailyMed, Aug 28, 2026).
The shared dose ladder
Both labels start at 2.5 mg once weekly and raise the dose in 2.5 mg steps, with at least 4 weeks on each dose before the next step. Titration means raising the dose in steps. The labels differ in why a step happens and where it stops.
| Weeks | Mounjaro | Zepbound |
|---|---|---|
| 1–4 | 2.5 mg (start) | 2.5 mg (start only; not a maintenance dose) |
| 5–8 | 5 mg, if more glycemic control is needed | 5 mg (maintenance option, weight) |
| 9–12 | 7.5 mg, if needed | 7.5 mg (escalation step) |
| 13–16 | 10 mg, if needed (children’s maximum) | 10 mg (maintenance option, weight and sleep apnea) |
| 17–20 | 12.5 mg, if needed | 12.5 mg (escalation step) |
| 21 onward | 15 mg (adult maximum) | 15 mg (maintenance option; maximum) |
Sources: (DailyMed, Aug 27, 2026) (DailyMed, Aug 28, 2026)
Two label details drive the difference. The Mounjaro label escalates “if additional glycemic control is needed” and names no maintenance dose; 5, 10 and 15 mg are the doses studied in the adult glycemic SURPASS trials (DailyMed, Aug 27, 2026). The Zepbound label names maintenance doses and says to weigh treatment response and tolerability when choosing one (DailyMed, Aug 28, 2026). Neither label requires reaching 15 mg.
- Weekly dose (published steps)
- Modeled amount (mg-eq)
- Stable window
The chart is a one-compartment model with a 5-day half-life, shown as a relative amount rather than a blood level. The Mounjaro dosing schedule and the Zepbound dosing schedule go step by step. The tirzepatide titration tool puts any ladder on a calendar, and the tirzepatide plotter charts a weekly schedule. Any change to a dose is a decision for your prescriber.
Pens, vials and strengths
The current US labels for both brands list the same four presentations and the same strengths (DailyMed, Aug 27, 2026) (DailyMed, Aug 28, 2026).
| Presentation | Doses per unit | Volume per dose | Strengths |
|---|---|---|---|
| Single-dose pen | 1 | 0.5 mL | 2.5, 5, 7.5, 10, 12.5, 15 mg |
| Single-dose vial | 1 | 0.5 mL | 2.5, 5, 7.5, 10, 12.5, 15 mg |
| Multi-dose vial | 4 | 0.6 mL | 10 to 60 mg per 2.4 mL |
| Single-patient-use KwikPen | 4 | 0.6 mL | 4 doses of 2.5 to 15 mg |
Sources: (DailyMed, Aug 27, 2026) (DailyMed, Aug 28, 2026)
Lilly announced the label expansion adding the four-dose Zepbound KwikPen on Feb 23, 2026 (Eli Lilly, Feb 23, 2026). Lilly sells Zepbound single-dose vials only through LillyDirect (Eli Lilly, Oct 19, 2026). We did not find the date the KwikPen and multi-dose vial were added to the Mounjaro label, so we do not state one.
The labels add a few presentation-specific cautions. Both labels say the KwikPen is not recommended for self-administration by people who are visually impaired (DailyMed, Aug 27, 2026) (DailyMed, Aug 28, 2026). The Mounjaro label adds that its KwikPen is not recommended for self-administration by pediatric patients (DailyMed, Aug 27, 2026). When the presentation changes, both labels call for new training and the new Instructions for Use. A dose from a multi-dose vial is 0.6 mL, not 0.5 mL, even when the milligrams match. The pen-to-vial tool and the tirzepatide units tool show that arithmetic for reference.
Storage, missed doses and timing
These rules are the same in both labels (DailyMed, Aug 27, 2026) (DailyMed, Aug 28, 2026).
| Rule | Mounjaro and Zepbound |
|---|---|
| Single-dose pen or vial, refrigerated | 2–8 °C (36–46 °F) |
| Single-dose pen or vial, unrefrigerated | Up to 21 days total, not above 30 °C (86 °F) |
| Unopened multi-dose vial or KwikPen at room temperature | Discard after 30 days |
| Opened multi-dose vial or KwikPen | Discard after 30 days at room temperature, 30 days after first use, or 4 weekly doses, whichever comes first |
| Missed dose | Take within 4 days (96 hours); after that, skip it |
| Changing the dosing day | Allowed if doses are at least 3 days (72 hours) apart |
Sources: (DailyMed, Aug 27, 2026) (DailyMed, Aug 28, 2026)
The 21-day allowance applies only to single-dose pens and vials, not to KwikPens or multi-dose vials. Both labels allow a dose at any time of day, with or without meals. If a missed dose or a warm pen leaves you unsure, ask your pharmacist.
Half-life and how long it stays in the body
The two labels describe the same drug with slightly different numbers because they summarize different study populations (DailyMed, Aug 27, 2026) (DailyMed, Aug 28, 2026).
| Measure | Mounjaro label | Zepbound label |
|---|---|---|
| Elimination half-life | About 5 days | About 5 to 6 days |
| Time to peak level | 8 to 72 hours | Median 24 hours (range 8 to 72) |
| Absolute bioavailability | 80% | 80% |
| Time to steady state | 4 weeks of weekly dosing | 4 weeks of weekly dosing |
Sources: (DailyMed, Aug 27, 2026) (DailyMed, Aug 28, 2026)
With a 5-day half-life, our model puts the weekly accumulation ratio at about 1.61, and about 38% of a weekly dose remains after 7 days of pure decay. The labels give their own reason for the slow ladder: the Mounjaro label says to follow the starting dose and escalation schedule “to reduce the risk of gastrointestinal adverse reactions” (DailyMed, Aug 27, 2026).
Key trials behind each label
Mounjaro’s label rests on the SURPASS program in type 2 diabetes. Zepbound’s rests on SURMOUNT in obesity and two sleep apnea studies. These trials enrolled different people, ran for different lengths and used different analyses, so the rows below cannot be compared with each other.
| Trial | Label | Who and how long | Result | Analysis |
|---|---|---|---|---|
| SURPASS-2 | Mounjaro | 1,879 adults with type 2 diabetes on metformin; 40 weeks; open-label | HbA1c −2.0, −2.2, −2.3 points (5, 10, 15 mg) vs −1.9 (semaglutide 1 mg) | Label, modified intent-to-treat (multiple imputation) |
| SURPASS-2, weight | Mounjaro | Same trial | −7.6, −9.3, −11.2 kg vs −5.7 kg | Label, modified intent-to-treat |
| SURPASS-CVOT | Mounjaro | 13,299 adults with type 2 diabetes and established cardiovascular disease; median 210.1 weeks; vs dulaglutide 1.5 mg | Cardiovascular events 12.1% vs 13.0%; hazard ratio 0.92 | Label; non-inferior, superiority not shown |
| SURMOUNT-1 | Zepbound | 2,539 adults with obesity or overweight, no diabetes; 72 weeks | Weight −15.0%, −19.5%, −20.9% (5, 10, 15 mg) vs −3.1% placebo | Treatment-regimen estimand |
| Sleep apnea Study 5 and Study 6 | Zepbound | 469 adults with sleep apnea and obesity; 52 weeks | AHI −25.3 vs −5.3 events per hour (no PAP); −29.3 vs −5.5 (on PAP) | Label, modified intent-to-treat; least-squares mean |
Sources: (N Engl J Med, Aug 5, 2021) (DailyMed, Aug 27, 2026) (N Engl J Med, Jul 21, 2022) (DailyMed, Aug 28, 2026)
A few reading notes. The SURMOUNT-1 figures use the treatment-regimen estimand, which counts everyone randomized whether or not they kept taking the drug (N Engl J Med, Jul 21, 2022). SURPASS-2 was open-label, and its weight loss in people with diabetes is not a weight-loss indication for Mounjaro. In SURPASS-CVOT the 95.3% confidence interval for the hazard ratio ran from 0.83 to 1.01 (DailyMed, Aug 27, 2026). The sleep apnea studies escalated Zepbound to the highest tolerated dose of 10 or 15 mg and measured AHI, the apnea-hypopnea index, on a sleep study; Study 5 enrolled people not using PAP therapy and Study 6 people using it (DailyMed, Aug 28, 2026).
Side-effect tables also come from different pools. At 15 mg, nausea was 18% in the Mounjaro diabetes pool (4% placebo) and 28% in the Zepbound obesity pool (8% placebo) (DailyMed, Aug 27, 2026) (DailyMed, Aug 28, 2026). The pools differ in population and cutoff, so the gap is not a head-to-head finding.
Switching or taking them together
The Zepbound label says coadministration with other tirzepatide-containing products, or with any GLP-1 receptor agonist, is not recommended (DailyMed, Aug 28, 2026). Mounjaro contains tirzepatide, so the two are not used at the same time.
Neither label names the other brand, and neither gives a conversion or switching schedule between them. The milligram strengths are identical, and so is the step ladder. Whether a switch fits, and at what dose, depends on the indication, the reason for the change and coverage. Talk to your prescriber before switching.
Compounded tirzepatide is a different product. The FDA does not review compounded drugs for safety, effectiveness or quality before they are marketed (FDA, Oct 1, 2026), and compounded products are not interchangeable with either brand.
Coverage and savings programs, compared without prices
Because the labeled uses differ, a health plan may treat the two brands differently. Lilly also runs separate programs. The terms below are as shown on Lilly’s pages on Oct 19 and Oct 20, 2026; Lilly says terms can change at any time.
| Program detail | Mounjaro | Zepbound |
|---|---|---|
| Savings card applies to | Single-dose pen only | Single-dose pen; a separate card covers the KwikPen |
| Tiers | Covered and not-covered commercial plans | Covered and not-covered commercial plans, plus the KwikPen card |
| Government insurance | Excluded | Excluded from the cards |
| Card expiration | Dec 31, 2026 | Dec 31, 2026 |
| Other routes Lilly lists | LillyDirect self-pay, single-dose pen | LillyDirect self-pay (KwikPen or vials); retail KwikPen card since Mar 16, 2026; Medicare GLP-1 Bridge for weight management |
Sources: (Eli Lilly, Oct 19, 2026) (Eli Lilly, Sep 1, 2026) (Eli Lilly, Oct 19, 2026) (Eli Lilly, Oct 19, 2026) (Eli Lilly, Mar 16, 2026)
The Medicare GLP-1 Bridge applies to eligible Part D patients with a Zepbound prescription for weight management, and Lilly says it does not guarantee coverage (Eli Lilly, Sep 1, 2026). The cards themselves still exclude Medicare and Medicaid. For current amounts, caps and fill limits, see the Mounjaro savings card guide and the Zepbound savings card guide.
Frequently asked questions
What is the difference between Mounjaro and Zepbound?
- The drug is the same: both contain tirzepatide made by Eli Lilly, in the same six strengths. The labels differ. Mounjaro is approved for type 2 diabetes (adults and children 10 and older) and for lowering cardiovascular event risk in adults with type 2 diabetes. Zepbound is approved for chronic weight management and for moderate to severe obstructive sleep apnea in adults with obesity. Zepbound names maintenance doses; Mounjaro does not.
Is Mounjaro the same as Zepbound?
- Same molecule, different products. Per the FDA labels, both are tirzepatide, start at 2.5 mg once weekly, step up by 2.5 mg after at least 4 weeks, top out at 15 mg in adults, and share the same storage and missed-dose rules. They are approved for different conditions, carry different brand names and savings cards, and are covered separately by insurance plans. The Zepbound label says using it with other tirzepatide-containing products is not recommended.
Can you take Mounjaro for weight loss?
- Mounjaro is not FDA approved for weight loss. Lilly's May 13, 2022 approval release said it is not indicated for weight loss, and the current label lists only type 2 diabetes uses. The tirzepatide brand labeled for chronic weight management is Zepbound. People with type 2 diabetes did lose weight on Mounjaro in SURPASS-2 (−7.6 to −11.2 kg at week 40 in the label). Whether a medicine is right for you is a decision to make with your prescriber.
Can you switch from Mounjaro to Zepbound?
- Neither label names the other brand or gives a switching schedule. What the labels do say: both use the same strengths and the same 2.5 mg step ladder, and the Zepbound label says coadministration with other tirzepatide-containing products is not recommended, so the two are not used at the same time. Zepbound's weight indication covers adults with obesity, or overweight with at least one weight-related condition. Your prescriber decides whether to switch and at what dose.
Are Mounjaro and Zepbound doses the same?
- The strengths are identical: 2.5, 5, 7.5, 10, 12.5 and 15 mg. Both labels start at 2.5 mg once weekly and allow 2.5 mg increases after at least 4 weeks on the current dose, up to 15 mg in adults. The difference is the target. Zepbound names maintenance doses of 5, 10 or 15 mg for weight and 10 or 15 mg for sleep apnea. Mounjaro escalates only if more glycemic control is needed, with a 10 mg maximum for children 10 and older.
Can you take Mounjaro and Zepbound together?
- The Zepbound label says this is not recommended. Its prescribing information says coadministration with other tirzepatide-containing products, or with any GLP-1 receptor agonist, is not recommended. Mounjaro is a tirzepatide-containing product. Talk to your prescriber if you have been prescribed both.
Sources
- MOUNJARO (tirzepatide) injection, for subcutaneous use - Full Prescribing Information, Medication Guide and Instructions for Use (DailyMed SPL set ID d2d7da5d-ad07-4228-955f-cf7e355c8cc0, version 40). U.S. National Library of Medicine (DailyMed) / Eli Lilly and Company, Aug 27, 2026. Accessed Oct 19, 2026.
- ZEPBOUND (tirzepatide) injection, for subcutaneous use - Full Prescribing Information, Medication Guide and Instructions for Use (DailyMed SPL set ID 487cd7e7-434c-4925-99fa-aa80b1cc776b, version 40). U.S. National Library of Medicine (DailyMed) / Eli Lilly and Company, Aug 28, 2026. Accessed Oct 19, 2026.
- FDA approves Lilly's Mounjaro™ (tirzepatide) injection, the first and only GIP and GLP-1 receptor agonist for the treatment of adults with type 2 diabetes. Eli Lilly and Company (investor.lilly.com), May 13, 2022. Accessed Oct 19, 2026.
- FDA Approves New Medication for Chronic Weight Management. U.S. Food and Drug Administration, Nov 8, 2023. Accessed Oct 19, 2026.
- FDA Approves First Medication for Obstructive Sleep Apnea. U.S. Food and Drug Administration, Dec 20, 2024. Accessed Oct 19, 2026.
- Zepbound (tirzepatide), the most prescribed weight management medication in 2025, now available in multi-dose KwikPen. Eli Lilly and Company (investor.lilly.com), Feb 23, 2026. Accessed Oct 19, 2026.
- Media Statement: Zepbound (tirzepatide) KwikPen now available at self-pay pricing at major pharmacies nationwide in addition to LillyDirect. Eli Lilly and Company (investor.lilly.com), Mar 16, 2026. Accessed Oct 19, 2026.
- Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med 2022;387(3):205-216 (Jastreboff AM et al.; PubMed PMID 35658024; doi:10.1056/NEJMoa2206038), Jul 21, 2022. Accessed Oct 19, 2026.
- Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes. N Engl J Med 2021;385(6):503-515 (Frías JP et al.; PubMed PMID 34170647; doi:10.1056/NEJMoa2107519), Aug 5, 2021. Accessed Oct 19, 2026.
- Savings & Coverage | Mounjaro® (tirzepatide). Eli Lilly and Company (mounjaro.lilly.com), Oct 19, 2026. Accessed Oct 19, 2026.
- Savings & Insurance Options | Zepbound® (tirzepatide). Eli Lilly and Company (zepbound.lilly.com; page code CMAT-26402 09/2026), Sep 1, 2026. Accessed Oct 19, 2026.
- Authentic Mounjaro® (tirzepatide) Shipped to You | LillyDirect®. Eli Lilly and Company (LillyDirect), Oct 19, 2026. Accessed Oct 19, 2026.
- Authentic Zepbound® (tirzepatide) Shipped to You | LillyDirect®. Eli Lilly and Company (LillyDirect), Oct 19, 2026. Accessed Oct 19, 2026.
- FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss. U.S. Food and Drug Administration, Oct 1, 2026. Accessed Oct 19, 2026.