Tirzepatide
Also sold as Mounjaro, Zepbound.
- Half-life
- 120 h
- Steady state
- ~25 d
- Class
- GLP-1 / GIP
- Category
- GLP-1
Published population averages. Steady state is the usual five half-life rule of thumb, not a measurement. See peptide half-life, explained.
Overview
Tirzepatide is a first-in-class dual GLP-1/GIP receptor agonist developed by Eli Lilly. It simultaneously activates both incretin pathways, producing superior glycemic and weight-loss outcomes compared to selective GLP-1 agonists in head-to-head trials. Marketed as Mounjaro (T2DM) and Zepbound (obesity).
How it works
Activates both GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) receptors. The dual agonism enhances insulin secretion beyond GLP-1 alone, improves lipid metabolism via GIP-mediated adipocyte signaling, and produces stronger appetite suppression through combined hypothalamic and brainstem pathways.
Half-life and peak
Terminal half-life is approximately 5 days (~120 hours), supporting once-weekly dosing. Steady state reached in 4 weeks. Tmax occurs at approximately 8–72 hours post-dose depending on injection site.
What it is studied for
SURPASS clinical program (T2DM), SURMOUNT clinical program (obesity), head-to-head vs semaglutide, cardiovascular and metabolic syndrome outcomes.
Research status
FDA-approved for T2DM (Mounjaro, 2022) and chronic weight management (Zepbound, 2023). SURMOUNT-1 showed up to 22.5% weight loss. Cardiovascular outcomes trial (SURPASS-CVOT) ongoing.
Sources
- Tirzepatide SURPASS-1 trial — NEJM · doi.org
- SURMOUNT-1 obesity trial — NEJM · doi.org
- Tirzepatide drug information — FDA · fda.gov
- Tirzepatide PK/PD characterization · doi.org
Educational reference only. This page describes what is published about a compound; it is not medical advice, not a recommendation to take anything, and not a dosing guide. Several compounds in this catalog are investigational and are not approved medicines. Talk to a doctor.
Guides that cover it
How to track a GLP-1 protocol properly
A weekly injection is easy to take and surprisingly easy to lose track of. What to record, why the date matters more than the dose, and how to keep a titration legible to the person who prescribed it.
Ozempic, Wegovy, Mounjaro, Zepbound: which is which
Four brand names, two molecules, and a lot of confusion. What each name actually refers to, why the same drug is sold twice under different labels, and what that means when you are keeping a record.
Peptide half-life, explained
Half-life is the number that decides how often something is injected, how long it takes to settle, and how long it lingers after you stop. Here is what it does tell you, and the three things people assume it tells them that it does not.