GIP and GLP-1 receptor agonist (a "dual agonist")
Tirzepatide (Zepbound, Mounjaro): status, trials and tools
Status as of
FDA approved as Mounjaro (type 2 diabetes) and Zepbound (weight management, obstructive sleep apnea).
Source: DailyMed, Aug 28, 2026. Also called: Zepbound, Mounjaro, LY3298176.
Short answer
Tirzepatide is Eli Lilly's once-weekly GIP and GLP-1 receptor agonist, sold as Mounjaro for type 2 diabetes (FDA approved May 13, 2022) and Zepbound for weight management (November 8, 2023) and sleep apnea with obesity (December 20, 2024). Half-life: about 5 days. In SURMOUNT-1, 15 mg gave −20.9% at 72 weeks (treatment-regimen estimand). As of Oct 19, 2026.
Tirzepatide tools
- Tirzepatide level plotter
One-compartment Bateman model, published ladder presets.
- Tirzepatide mg to units
mg to U-100 units, concentration and mL.
- Tirzepatide reconstitution
Concentration from vial mg and water mL, units on U-100 syringes.
- Tirzepatide cost
Total mg for a schedule or published ladder, whole and fractional vials.
- Tirzepatide titration schedule
Published trial and label ladders, week-by-week dated table.
- Tirzepatide storage dates
Label-sourced in-use periods, discard-by date and days left.
Status timeline
-
Zepbound KwikPen approved; self-pay launch
-
Zepbound approved for obstructive sleep apnea
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FDA confirms the tirzepatide shortage is resolved
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Zepbound approved for chronic weight management
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Mounjaro approved for type 2 diabetes
Pharmacokinetic parameters
| Parameter | Published | Model value |
|---|---|---|
| Half-life | FDA labels: Zepbound states approximately 5–6 days (pharmacokinetics section) and approximately 5 days (overdosage section); Mounjaro states approximately 5 days. The model uses 5 days. source | 5 days |
| Time to peak | FDA label (Zepbound): median time to maximum concentration 24 hours, range 8 to 72 hours. The model uses 24 hours. source | 24 h |
| Bioavailability | 80% absolute (label) | 1 (relative) |
Key trial results
| Trial | Population | Weeks | Arm | Result | Comparator | Analysis |
|---|---|---|---|---|---|---|
| SURMOUNT-1 | Obesity or overweight without diabetes | 72 | 15 mg | −20.9% body weight | Placebo −3.1% | Treatment-regimen estimand |
| SURMOUNT-5 | Obesity without diabetes (open label) | 72 | 10 or 15 mg | −20.2% body weight | Semaglutide 1.7/2.4 mg −13.7% | Least-squares mean; estimand not named in abstract |
| SURPASS-2 | Type 2 diabetes on metformin | 40 | 15 mg | HbA1c −2.30 points | Semaglutide 1 mg −1.86 | Primary endpoint |
Published dose ladders
- FDA label ladder to 15 mg
2.5 → 5 → 7.5 → 10 → 12.5 → 15 mg
- FDA label ladder to 5 mg
2.5 → 5 mg
What tirzepatide is
Tirzepatide is a once-weekly medicine from Eli Lilly that activates two gut-hormone receptors, GIP and GLP-1. When the FDA approved it as Mounjaro on May 13, 2022, Lilly described it as the first and only GIP and GLP-1 receptor agonist. (Eli Lilly, May 13, 2022) It is given as a subcutaneous dose once a week.
The FDA labels give an elimination half-life of approximately 5–6 days (Zepbound) or approximately 5 days (Mounjaro), a median time to peak of 24 hours, bioavailability of 80%, and steady state after 4 weeks of weekly dosing. (DailyMed, Aug 28, 2026) (DailyMed, Aug 27, 2026) The tirzepatide half-life guide shows the decay math, and the tirzepatide dose plotter models any schedule.
| Date | Event |
|---|---|
| May 13, 2022 | Mounjaro approved for glycemic control in adults with type 2 diabetes |
| November 8, 2023 | Zepbound approved for chronic weight management |
| December 20, 2024 | Zepbound approved for moderate to severe obstructive sleep apnea in adults with obesity |
| February 23, 2026 | Lilly announces FDA label expansion adding the four-dose Zepbound KwikPen |
The current Mounjaro label (August 2026) also covers children 10 years and older with type 2 diabetes and reducing major cardiovascular events in adults with type 2 diabetes at high cardiovascular risk. (DailyMed, Aug 27, 2026)
Brands and presentations
Zepbound and Mounjaro contain the same drug in the same strengths. Both labels list four presentations, all ready-to-use solutions. (DailyMed, Aug 28, 2026)
| Presentation | Doses | Strengths |
|---|---|---|
| Single-dose pen | 1 | 2.5, 5, 7.5, 10, 12.5 or 15 mg per 0.5 mL |
| Single-dose vial | 1 | 2.5, 5, 7.5, 10, 12.5 or 15 mg per 0.5 mL |
| Multi-dose vial | 4 | 2.5 to 15 mg per 0.6 mL dose (10 to 60 mg per 2.4 mL) |
| Single-patient-use KwikPen | 4 | 2.5 to 15 mg per dose (10 to 60 mg per 2.4 mL) |
Both labels start at 2.5 mg once weekly and allow 2.5 mg increases after at least 4 weeks on the current dose, to a maximum of 15 mg (10 mg for children on Mounjaro). Zepbound names 5, 10 or 15 mg as maintenance doses for weight and 10 or 15 mg for sleep apnea; Mounjaro names none. (DailyMed, Aug 28, 2026) (DailyMed, Aug 27, 2026) The full ladder is in the tirzepatide dosage chart, and the titration calculator puts it on a calendar. Your prescriber decides the dose.
Key trials
Three trials anchor most of what is said about tirzepatide. They differ in population, comparator, length and analysis, so their numbers should not be compared directly.
| Trial | Design | Main result |
|---|---|---|
| SURMOUNT-1 (2022) | 2,539 adults with obesity or overweight, no diabetes; 5, 10, 15 mg vs placebo; 72 weeks | Weight change −15.0%, −19.5%, −20.9% vs −3.1% (treatment-regimen estimand) |
| SURMOUNT-5 (2025) | 751 adults with obesity, no diabetes; open-label; tirzepatide 10/15 mg vs semaglutide 1.7/2.4 mg; 72 weeks | Weight change −20.2% vs −13.7% (least-squares mean); waist −18.4 vs −13.0 cm |
| SURPASS-2 (2021) | 1,879 adults with type 2 diabetes on metformin; open-label; 5, 10, 15 mg vs semaglutide 1 mg; 40 weeks | HbA1c −2.01, −2.24, −2.30 vs −1.86 percentage points |
SURMOUNT-1’s figures use the treatment-regimen estimand, which counts everyone randomized regardless of whether they stopped treatment; the Zepbound label reports the same numbers. The SURMOUNT-5 abstract does not name its estimand, so we do not label it. In SURPASS-2, weight loss was greater than with semaglutide 1 mg by 1.9, 3.6 and 5.5 kg at 5, 10 and 15 mg. For side-effect rates by dose, see tirzepatide side effects; for the head-to-head, see tirzepatide vs semaglutide.
Compounding status
Compounded tirzepatide is not Zepbound or Mounjaro. The FDA says compounded drugs are not FDA approved and that it “does not review compounded drugs for safety, effectiveness or quality before they are marketed.” (FDA, Oct 1, 2026) As of May 31, 2026, the FDA reported more than 730 adverse-event reports associated with compounded tirzepatide.
| Date | Event |
|---|---|
| December 15, 2022 | Tirzepatide added to the FDA drug shortage list |
| October 2, 2024 | FDA determines the shortage is resolved |
| December 19, 2024 | FDA reaffirms the resolution after reevaluation |
| March 19, 2025 | Enforcement discretion ends for 503B outsourcing facilities |
Compounded products often come as powders that need mixing, which the brand products never do. The tirzepatide reconstitution chart explains that arithmetic and why it does not apply to Zepbound or Mounjaro.
Tools and guides
Tirzepatide guides
- Missed a GLP-1 dose: what each FDA label says
Dosing schedules
- Mounjaro dosing schedule: what the FDA label says
Dosing schedules
- Mounjaro savings card: eligibility, price and self-pay (2026)
Savings and cost
- Tirzepatide half-life: how long it stays in your system
Pharmacokinetics
- Tirzepatide reconstitution chart: vial × water → units
Reconstitution charts
- Zepbound dosing schedule: what the FDA label says
Dosing schedules
- GLP-3 vs GLP-1
Comparison
- Mounjaro vs Zepbound
Comparison
- Retatrutide vs Tirzepatide
Comparison
- Tirzepatide vs Semaglutide
Comparison
- Wegovy vs Zepbound
Comparison
Frequently asked questions
Is tirzepatide FDA approved?
- Yes. The FDA approved tirzepatide as Mounjaro for glycemic control in adults with type 2 diabetes on May 13, 2022 (per Lilly's release), as Zepbound for chronic weight management on November 8, 2023, and Zepbound for moderate to severe obstructive sleep apnea in adults with obesity on December 20, 2024. Compounded tirzepatide is not FDA approved.
What is the difference between Zepbound and Mounjaro?
- Same molecule, same six strengths (2.5 to 15 mg), different indications. Zepbound is labeled for chronic weight management and for sleep apnea in adults with obesity, with named maintenance doses. Mounjaro is labeled for glycemic control in type 2 diabetes (adults and children 10 and older) and cardiovascular risk reduction, and steps up only if more glycemic control is needed.
How does tirzepatide work?
- Tirzepatide is a single molecule that activates two hormone receptors: GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1). Lilly described Mounjaro at approval as the first and only GIP and GLP-1 receptor agonist. Its roughly 5-day half-life allows once-weekly dosing.
Is compounded tirzepatide the same as Zepbound?
- No. The FDA says compounded drugs are not FDA approved and are not reviewed for safety, effectiveness or quality before marketing. The FDA declared the tirzepatide shortage resolved on October 2, 2024, and reaffirmed it on December 19, 2024. As of May 31, 2026, the FDA had more than 730 adverse-event reports tied to compounded tirzepatide.
How long does tirzepatide stay in your system?
- The Zepbound label gives a half-life of approximately 5–6 days and the Mounjaro label approximately 5 days. By arithmetic, about 3% of a single dose remains after five half-lives (about 25 days at 5 days each). The labels do not state a washout period; ask your prescriber.
Sources
- 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) 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.
- 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), 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.
- 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 as Compared with Semaglutide for the Treatment of Obesity. N Engl J Med 2025;393(1):26-36 (Aronne LJ et al.; PubMed PMID 40353578; doi:10.1056/NEJMoa2416394), Jul 3, 2025. 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.
- Resolution of Tirzepatide Injection Product Shortage and Supply Status (CDER Drug Shortage Staff memorandum). U.S. Food and Drug Administration, Dec 19, 2024. 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.