Last reviewed: October 2026 · Cleared Peptides research team
Research use only. Tirzepatide (CP-T): Research Guide to the Dual GIP/GLP-1 Receptor Agonist is supplied for laboratory research. It is not a drug, food, cosmetic, or dietary supplement. It is not FDA-approved. It is not for human or veterinary administration. This page does not give a dose or a method of administration. A study cited on this page describes that study’s own test article. It does not make this lot an approved medicine. To check a fact, open the PubMed or DOI link, confirm the authors and year, and match the paper’s compound name, CAS number, or sequence to the specification table. The full method is on the research desk page. Identity and purity for a lot are only what that lot’s certificate of analysis reports. An HPLC percentage is not a sterility result and not an endotoxin result unless the certificate prints those tests.
Tirzepatide (development code LY3298176) is a synthetic, lipidated 39-amino-acid peptide characterized as a dual agonist of the glucose-dependent insulinotropic polypeptide receptor (GIPR) and the glucagon-like peptide-1 receptor (GLP-1R). It is a widely used reference compound for studying how co-activation of these two incretin receptors differs from GLP-1R activation alone.
In this guide:
- Structure and identifiers
- Receptor pharmacology
- Signaling bias
- Comparison with related compounds
- Purity testing
- Analytical testing
- FAQ
Other names
The heading on this page stays the published compound name, because that is the name researchers search. The catalog code is the label Cleared Peptides prints on that research material. It is the same substance, not a second compound, and it is not a CAS name.
| Published name | Tirzepatide |
|---|---|
| Development code | LY3298176 |
| CAS number | 2023788-19-2 |
| Catalog code | CP-T |
| Informal names | Tirz. This code is not CP-Reta and not CP-SEMA. |
Tirzepatide Structure and Identifiers
| Name | Tirzepatide |
|---|---|
| Development code | LY3298176 |
| CAS number | 2023788-19-2 |
| PubChem CID | 166567236 |
| Molecular formula | C225H348N48O68 |
| Molecular weight | ≈4813.5 g/mol |
| Length | 39 amino acids |
| Backbone | Based on the native GIP sequence, with Aib residues at positions 2 and 13 and a C-terminal amide |
| Lipidation | C20 fatty diacid on Lys20 through a γGlu–2×OEG linker |
| Physical form (research grade) | Lyophilized white powder |
Like other long-acting incretin-receptor peptides, tirzepatide combines protease-resistant non-coded residues (Aib) with a fatty diacid side chain that binds serum albumin. Its sequence borrows from GIP, GLP-1 and exendin-4, which is why it is often described as an “imbalanced” dual agonist that favors the GIP receptor.
Tirzepatide Receptor Pharmacology (In-Vitro)
In published assays with recombinant human receptors, tirzepatide shows potency at GIPR comparable to native GIP, and lower potency at GLP-1R relative to native GLP-1. It has negligible reported activity at the glucagon receptor — the key pharmacological difference from retatrutide.
Signaling Bias at the GLP-1 Receptor
A frequently cited finding is that tirzepatide shows biased agonism at GLP-1R: it favors cAMP generation over β-arrestin recruitment, and produces less receptor internalization than native GLP-1 in cell models. This makes tirzepatide a useful tool for laboratories studying biased signaling and receptor trafficking of class B GPCRs.
Tirzepatide Compared with Semaglutide and Retatrutide
| Compound | Receptors (in vitro) | Lipid chain | CAS |
|---|---|---|---|
| Semaglutide | GLP-1R | C18 diacid | 910463-68-2 |
| Tirzepatide | GIPR + GLP-1R | C20 diacid | 2023788-19-2 |
| Retatrutide | GIPR + GLP-1R + GCGR | C20 diacid | 2381089-83-2 |
Read the full tirzepatide vs retatrutide vs semaglutide comparison.
Tirzepatide Purity and Analytical Testing
Research-grade tirzepatide should be supplied with HPLC purity data, mass-spectrometry identity confirmation and a lot-specific COA. Every lot of Cleared Peptides tirzepatide (CP-T) is independently tested, and results are posted on our COA page. Store lyophilized material at −20 °C, sealed and protected from light.
Research materials referenced in this guide
Analytical testing notes for Tirzepatide
Tirzepatide is identified in this guide as CAS 2023788-19-2, formula C225H348N48O68, listed mass ≈4813.5 g/mol. An identity test compares a measurement with those values. A mass spectrum is the usual measurement for a peptide. FTIR, when a certificate uses it, is a supporting infrared fingerprint and is less specific for closely related sequences.
Tirzepatide carries a fatty-acid or other lipophilic modification, so it is among the later-eluting peptides on a C18 column. Laboratories often raise the acetonitrile fraction, the column temperature, or move to a C8 or C4 column so the main peak is sharp enough to integrate. The mass used for identity has to include the lipid chain and linker, not only the amino-acid backbone. Area-percent purity still ignores water and counterion.
HPLC purity for this material is an area-percent result at the wavelength and gradient the laboratory states, commonly ultraviolet detection near 214 nm on a reversed-phase column. The instrument is a gradient pump, injector, column oven, and UV or diode-array detector. That percentage is not the number of milligrams in the vial. Water, acetate, trifluoroacetate, and other UV-silent material can dominate the gross weight while the purity figure stays high. Net peptide content, from an assay or amino-acid analysis, is the separate result to read when the certificate reports it.
A sterility test and an endotoxin test are not included in a chemical purity result. The compendial sterility test is a culture method (USP <71>): membrane filtration or direct inoculation into fluid thioglycollate medium and soybean-casein digest medium, incubated for 14 days. A PCR sterility screen uses a thermal cycler to detect microbial DNA and is a different method. The endotoxin test (USP <85> LAL, or USP <86> recombinant Factor C) reports endotoxin units with an incubating reader or a cartridge reader. Use a result only when that method is printed on the lot certificate. One published example in this catalog states that the report does not cover microbial contamination or endotoxins. The full description of equipment, standards, and how US laboratory accreditation works is in peptide analytical testing. Lot records are on the COA page.
Frequently Asked Questions
What is tirzepatide?
Tirzepatide (LY3298176) is a synthetic 39-residue lipidated peptide characterized in vitro as a dual agonist of the GIP and GLP-1 receptors.
What is the CAS number of tirzepatide?
2023788-19-2. Molecular formula C225H348N48O68, MW ≈4813.5 g/mol.
How is tirzepatide different from retatrutide?
Tirzepatide acts at GIPR and GLP-1R; retatrutide additionally activates the glucagon receptor.
Is CP-T the same as tirzepatide?
Yes. CP-T is Cleared Peptides’ code for research-grade tirzepatide, verified per lot by HPLC and MS.
Is tirzepatide from Cleared Peptides for human use?
No. It is for laboratory research use only, not for human or veterinary use.
Written by the Cleared Peptides Research Desk, the editorial desk of Cleared Wellness Group LLC. This is not a personal profile of a physician or a scientist, and it is not a fictional author. The checking method is public on the research desk page. Last reviewed October 2026.
Tirzepatide research note: imbalanced dual agonism, not a 1:1 mixture
Research use only. CP-T is lyophilized tirzepatide for laboratory research, development code LY3298176, CAS 2023788-19-2. It is not the finished drug studied in the clinical papers, and this note does not repeat those papers’ doses.
What Willard actually reported
Calling tirzepatide a “dual agonist” is incomplete. Willard, Douros, Gabe, and colleagues (JCI Insight, 2020) reported that tirzepatide engages the GIP receptor more than the GLP-1 receptor at the doses they modeled, and that at the GLP-1 receptor it favors cAMP generation over β-arrestin recruitment, with less receptor internalization than native GLP-1. In their islet experiments, β-arrestin1 limited the insulin response to GLP-1 but not to GIP or tirzepatide. The paper’s claim is an imbalanced and biased mechanism, not a blend of two hormones poured together. PubMed 32730231, DOI 10.1172/jci.insight.140532.
That is the laboratory question worth copying into an assay design: measure cAMP and β-arrestin at each receptor, and do not assume the two receptors are occupied equally. It is not a dosing question, and this page will not turn Willard’s occupancy model into one.
Where the molecule came from
Coskun, Sloop, Loghin, and colleagues described LY3298176 in Molecular Metabolism (2018) as a fatty-acid-modified peptide with dual GIP and GLP-1 receptor activity, characterized in receptor-expressing cell lines and in mice, and then in a phase 1 program. PubMed 30473097, DOI 10.1016/j.molmet.2018.09.009.
The catalog specification matches that chemical class: a 39-residue GIP-based sequence, Aib residues, a C20 diacid through a γGlu–(2×OEG) linker on Lys20, C-terminal amide, formula C225H348N48O68, mass about 4813.5 g/mol. Identity is the acylated mass. A deletion peptide or a peptide that never received the diacid can still look “mostly right” on a shallow chromatogram.
Clinical papers are about a drug article
Frias, Davies, Rosenstock, and colleagues compared once-weekly tirzepatide with semaglutide 1 mg in adults with type 2 diabetes (New England Journal of Medicine, 2021). PubMed 34170647, DOI 10.1056/NEJMoa2107519. Jastreboff, Aronne, Ahmad, and colleagues reported a phase 3 obesity trial of tirzepatide (New England Journal of Medicine, 2022). PubMed 35658024, DOI 10.1056/NEJMoa2206038.
Both papers randomize people to a sponsor’s drug product. CP-T is a research powder. Shared use of the name tirzepatide does not transfer the trial’s formulation, excipients, or regulatory file onto this lot. Glycated hemoglobin and body weight in those papers are trial endpoints. They are not an HPLC specification.
How to verify this note
- Open Willard 2020 and find the imbalance (more GIP-receptor engagement) and the GLP-1-receptor bias (cAMP over β-arrestin). If a secondary article says only “dual agonist,” it has dropped the finding.
- Match CAS 2023788-19-2 and Lys20 acylation to the table. Retatrutide’s lipid is on Lys17 and adds glucagon-receptor activity. The two codes, LY3298176 and LY3437943, are not interchangeable.
- Keep Frias 2021 and Jastreboff 2022 as human trials of a drug product. Keep the certificate as the lot record.
Selected References
Peer-reviewed literature on the compounds discussed in this guide, listed as scientific background for laboratory researchers. Citation does not imply endorsement by the authors or any use other than in-vitro research.
- Willard FS, et al. Tirzepatide is an imbalanced and biased dual GIP and GLP-1 receptor agonist. JCI Insight. 2020;5(17). PubMed 32730231 · DOI
Laboratory note: solubility depends on salt form and solvent. This guide does not state a single solubility figure. Handling of lyophilized material is described in the peptide storage guide.
Research Use Only Notice
This guide is provided for educational and laboratory reference purposes. It summarizes published, primarily in-vitro and structural research literature and does not describe, recommend or imply any use in humans or animals. Products sold by Cleared Peptides are for laboratory research use only; they are not drugs, foods, cosmetics or dietary supplements, are not FDA-approved, and are not intended to diagnose, treat, cure, mitigate or prevent any disease. No dosing, administration or therapeutic information is provided.
