Tirzepatide
Also known as Mounjaro, Zepbound, LY3298176
Tirzepatide is a once-weekly peptide that activates both the GIP and GLP-1 receptors. Eli Lilly markets it as Mounjaro for type 2 diabetes and as Zepbound for chronic weight management and obstructive sleep apnea in adults with obesity.
By [Author name]. Licensed pharmacist review: pending. Last updated .
Identity
- Developer
- Eli Lilly and Company
- Brand names
- Mounjaro (2022), Zepbound (2023)
- Class
- GIP / GLP-1 receptor dual agonist
- Structure
- 39-amino-acid peptide based on the GIP sequence, with a C20 fatty diacid side chain
- Molecular formula
- C225H348N48O68 (PubChem)
- Molar mass
- about 4,813 g/mol
- Half-life
- About 5 days (prescribing information), which allows once-weekly administration.
What the research covers
Tirzepatide was the first dual GIP and GLP-1 receptor agonist to reach the market. Its development ran through two large trial programs: SURPASS in type 2 diabetes and SURMOUNT in chronic weight management.
SURMOUNT-1 (New England Journal of Medicine, 2022) enrolled adults with obesity or overweight without diabetes for 72 weeks and measured change in body weight against placebo. The SURPASS trials measured glycated hemoglobin against placebo and against other diabetes drugs.
The prescribing information lists nausea, diarrhea, decreased appetite, vomiting and constipation among the most common adverse reactions, and carries a boxed warning about thyroid C-cell tumors seen in rodents.
Summaries describe what studies measured, not what a substance does for anyone. Nothing here is a claim of benefit or a basis for use.
Regulatory status
- FDA-approved: Mounjaro (May 2022) for type 2 diabetes; Zepbound (November 2023) for chronic weight management, later also for moderate to severe obstructive sleep apnea in adults with obesity (December 2024).
- FDA removed tirzepatide from the drug shortage list on December 19, 2024, ending the allowance that let pharmacies compound copies. Grace periods ended February 18, 2025 (503A) and March 19, 2025 (503B).
- Tirzepatide sold as a "research chemical" is an unapproved drug in FDA's view; the 2026 warning letters to peptide sellers named it.
Anti-doping (WADA)
Not on the WADA Prohibited List as of the review date. Check the current list before competition.
Follow changes on the FDA peptide status tracker.
Tirzepatide questions
What is the difference between Mounjaro and Zepbound?
Same molecule, different approved uses and labeling. Mounjaro is approved for type 2 diabetes; Zepbound is approved for chronic weight management and obstructive sleep apnea with obesity.
Is compounded tirzepatide the same as Zepbound?
No. Compounded products are not FDA-approved and are not reviewed for safety, effectiveness or quality. Since the shortage ended, FDA generally does not allow compounding copies of the approved drug.