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Tirzepatide: FDA Status, Research and Uses

By Living+. Updated October 25, 2026.

Key takeaway

Tirzepatide acts on both the GIP and GLP-1 receptors. The FDA first approved it in 2022. It is sold as Mounjaro for type 2 diabetes and as Zepbound for weight and sleep apnea. FDA declared its shortage resolved in late 2024, which ended most compounding of copies [1, 2, 12].

At a glance

Where it stands

Checked

  • FDA approvedYesAs Mounjaro, Zepbound
  • Pharmacy compounding (503A)AllowedShortage resolved Oct 2, 2024 (re-affirmed Dec 19, 2024); 503A grace period ended after the Mar 5, 2025 court ruling. FDA does not intend to act on four or fewer essentially-copy prescriptions per month (page current Apr 1, 2026).
  • Outsourcing facilities (503B)Proposed noFDA proposed not to include tirzepatide on the 503B bulks list (Federal Register May 1, 2026; comment period extended to July 30, 2026 by a Jun 26, 2026 notice). No final decision found as of Oct 25, 2026. Not on the drug shortage list.
  • WADA (sport)Not listedNot prohibited; on the 2026 Monitoring Program (markers of semaglutide and tirzepatide, in and out of competition)
Same data as the Status Tracker. Checked against 10 sources

Key facts

Class
GIP receptor and GLP-1 receptor agonist (dual agonist) [1]
Length
39 amino acids, based on the GIP sequence, with a fatty side chain [3, 1]
Half-life
About 5 days (label) [1]
Route in studies
Under the skin once weekly [1, 2]
First studied
2018 (first human trials published); first U.S. approval 2022 [4, 5, 1]

How it works

Tirzepatide is one peptide that acts on two gut hormone receptors. It binds to and activates both the GIP receptor and the GLP-1 receptor. These are the targets of GIP and GLP-1, two hormones the gut releases after eating [1]. It is a chain of 39 amino acids, close in size to GIP and GLP-1 [3].

The label says the peptide is based on the GIP sequence. It contains an unusual amino acid called Aib at positions 2 and 13, and a fatty side chain attached at position 20 [1]. The fatty side chain lets it bind to albumin in the blood. This slows its clearance and gives a half-life of about 5 days, so it is given once a week [1].

In people with type 2 diabetes, tirzepatide raises insulin release and lowers glucagon, both only when blood sugar is high [1]. The label says it also lowers food intake and body weight [1]. Early lab work in mice found that it acted on both receptors and lowered body weight and food intake more than a GLP-1 drug alone [4].

The Mounjaro label says tirzepatide delays stomach emptying, so it may change how other pills taken by mouth are absorbed [1].

What the research shows

7 human trials

  1. 2025Human trial

    SURMOUNT-5

    751 adults with obesity, without type 2 diabetes Phase 3b, open-label, randomized, 72 weeks, tirzepatide vs semaglutide at highest tolerated doses

    Weight fell 20.2% with tirzepatide vs 13.7% with semaglutide [10]

    Read the study
  2. 2025Human trial

    SURPASS-CVOT

    13,299 adults with type 2 diabetes and heart or blood vessel disease Randomized, double-blind, noninferiority trial vs dulaglutide 1.5 mg weekly

    Heart death, heart attack or stroke: 12.2% with tirzepatide vs 13.1% with dulaglutide; noninferior [11]

    Read the study
  3. 2024Human trial

    SURMOUNT-OSA

    Adults with moderate to severe obstructive sleep apnea and obesity (two trials) Phase 3, randomized, double-blind, placebo-controlled, 52 weeks, 10 or 15 mg weekly

    Apnea-hypopnea index fell 25.3 and 29.3 events per hour vs about 5 with placebo [9]

    Read the study
  4. 2022Human trial

    SURMOUNT-1

    2,539 adults with obesity or overweight, without diabetes Phase 3, randomized, double-blind, placebo-controlled, 72 weeks, 5, 10 or 15 mg weekly

    Weight fell 15.0%, 19.5% and 20.9% with the three doses vs 3.1% with placebo [8]

    Read the study
  5. 2021Human trial

    SURPASS-2

    1,879 adults with type 2 diabetes Phase 3, open-label, randomized, 40 weeks, tirzepatide 5, 10 or 15 mg vs semaglutide 1 mg

    A1c fell 2.01 to 2.30 points with tirzepatide vs 1.86 with semaglutide [7]

    Read the study
  6. 2021Human trial

    SURPASS-1

    478 adults with type 2 diabetes, not on injectable diabetes drugs Phase 3, randomized, double-blind, placebo-controlled, 40 weeks

    A1c fell 1.87% to 2.07% with tirzepatide vs a 0.04% rise with placebo [6]

    Read the study
  7. 2018Human trial

    Phase 2 dose-finding (LY3298176)

    318 adults with type 2 diabetes Randomized, double-blind, placebo and dulaglutide controlled, 26 weeks, 1 to 15 mg weekly

    A1c fell 1.06% to 1.94% across doses vs 0.06% with placebo [5]

    Read the study

Doses used in studies

Label dosing for Mounjaro starts at 2.5 mg once weekly. The dose can rise in 2.5 mg steps after at least 4 weeks on the current dose. The maximum is 15 mg weekly for adults and 10 mg weekly for children 10 and older [1]. Zepbound also starts at 2.5 mg once weekly for 4 weeks. Maintenance doses are 5, 10 or 15 mg weekly for weight and 10 or 15 mg weekly for sleep apnea, with a 15 mg maximum [2].

Published trials used 5, 10 or 15 mg once weekly in SURPASS-1, SURPASS-2 and SURMOUNT-1, and 10 or 15 mg in SURMOUNT-OSA and SURMOUNT-5 [6, 7, 8, 9, 10]. The phase 2 trial tested 1, 5, 10 and 15 mg weekly [5].

Dosing is set by a licensed provider.

Side effects and safety

Mounjaro and Zepbound carry a boxed warning for thyroid C-cell tumors. Tirzepatide caused these tumors in rats, and it is not known if it causes them in people. It must not be used by people with a personal or family history of medullary thyroid cancer or MEN 2 [1, 2].

The most common side effects on the Mounjaro label are nausea, diarrhea, decreased appetite, vomiting, constipation, indigestion and stomach pain [1]. Zepbound label warnings include severe stomach side effects, kidney injury from dehydration, gallbladder disease, pancreatitis, allergic reactions, low blood sugar with insulin or sulfonylureas, diabetic eye problems, and a risk of breathing in stomach contents during anesthesia [2]. In SURMOUNT-1, side effects led 4.3% to 7.1% of tirzepatide users to stop, vs 2.6% on placebo [8].

FDA warns that compounded and other unapproved versions are not reviewed for safety or quality. As of May 31, 2026, FDA had more than 730 adverse event reports tied to compounded tirzepatide [13].

Common questions

Is tirzepatide FDA approved?

Yes. It was first approved in 2022. It is the active ingredient in Mounjaro and Zepbound [1, 2].

What is the difference between Mounjaro and Zepbound?

Both contain tirzepatide. Mounjaro is labeled for type 2 diabetes and heart risk in diabetes. Zepbound is labeled for weight reduction and for sleep apnea in adults with obesity [1, 2].

Is compounded tirzepatide still legal?

FDA declared the shortage resolved, and its grace periods ended in March 2025. Pharmacies may not regularly make copies of an approved drug. FDA does not plan to act on four or fewer such prescriptions a month [12].

Is tirzepatide still in shortage?

No. FDA says tirzepatide is not on its drug shortage list or on the 503B bulks list [12].

How is tirzepatide different from semaglutide?

Semaglutide acts on the GLP-1 receptor. Tirzepatide acts on both the GIP and GLP-1 receptors [1]. In SURMOUNT-5, weight fell 20.2% with tirzepatide vs 13.7% with semaglutide [10].

Is tirzepatide banned in sports?

No. It is not on the WADA 2026 Prohibited List. WADA monitors tirzepatide markers in its 2026 Monitoring Program [19, 20].

What are the most common side effects of tirzepatide?

Nausea, diarrhea, decreased appetite, vomiting, constipation, indigestion and stomach pain are the most common on the Mounjaro label [1].

How long does tirzepatide last in the body?

The label gives a half-life of about 5 days, which supports once-weekly dosing [1].

Sources

  1. DailyMed: Mounjaro (tirzepatide) injection label
  2. DailyMed: Zepbound (tirzepatide) injection label
  3. Cardiovascular Diabetology 2022: Tirzepatide, a dual GIP/GLP-1 receptor co-agonist (PMC)
  4. Coskun et al. 2018, Mol Metab: LY3298176 from discovery to clinical proof of concept (PubMed)
  5. Frias et al. 2018, Lancet: Phase 2 trial of LY3298176 (PubMed)
  6. Rosenstock et al. 2021, Lancet: SURPASS-1 (PubMed)
  7. Frías et al. 2021, NEJM: SURPASS-2 (PubMed)
  8. Jastreboff et al. 2022, NEJM: SURMOUNT-1 (PubMed)
  9. Malhotra et al. 2024, NEJM: SURMOUNT-OSA (PubMed)
  10. Aronne et al. 2025, NEJM: SURMOUNT-5 (PubMed)
  11. Nicholls et al. 2025, NEJM: SURPASS-CVOT (PubMed)
  12. FDA: FDA clarifies policies for compounders as national GLP-1 supply begins to stabilize
  13. FDA: Concerns with unapproved GLP-1 drugs used for weight loss
  14. FDA: FDA intends to take action against non-FDA-approved GLP-1 drugs (Feb 6, 2026)
  15. FDA: FDA proposes to exclude semaglutide, tirzepatide and liraglutide on 503B bulks list (Apr 30, 2026)
  16. Federal Register: List of bulk drug substances for which there is a clinical need under section 503B (May 1, 2026)
  17. FDA: FDA approves new medication for chronic weight management (Nov 8, 2023)
  18. FDA: FDA approves first medication for obstructive sleep apnea (Dec 20, 2024)
  19. WADA: 2026 Monitoring Program
  20. WADA: 2026 Prohibited List
  21. Federal Register: 503B bulks list notice, extension of comment period (Jun 26, 2026)

Updated October 25, 2026. Educational information, not medical advice.