What is GLP-3R (retatrutide)?
GLP-3R is Full Scale Peptides’ catalog designation for retatrutide (LY3437943), a synthetic 39-amino-acid peptide engineered as a triple receptor agonist targeting the GLP-1, GIP, and glucagon receptors. Originally developed by Eli Lilly, it remains an investigational compound. It has not been approved by the FDA or any other regulatory authority for any use, in any formulation, and is not available as an approved medicine anywhere. Full Scale Peptides supplies it as a lyophilized powder at ≥99% purity by HPLC, for laboratory research only.
Researchers encounter this compound under a range of supplier-specific codes. If you arrived here searching for a different designation, our GLP-3R compound name reference explains how the common catalog codes map to the underlying molecule.
Mechanism of action
The tri-receptor design is the basis of this compound’s research interest. GLP-1 and GIP signaling are studied for their roles in insulin secretion and lipid handling; glucagon receptor activation is examined in the context of hepatic substrate metabolism. Engaging all three pathways within a single molecule allows investigation of receptor cross-talk that selective single-target agonists cannot isolate.
Structurally, the peptide backbone carries a fatty acid moiety that extends circulating half-life in published preclinical models, which is why comparative work frequently pairs it against shorter-acting single- and dual-agonist reference compounds rather than against native ligands.
Documented research applications
- Insulin secretion pathways — downstream signaling cascades in cellular models
- Receptor cross-talk — comparative signaling against single- and dual-agonist controls
- Preclinical metabolic models — published in vitro and animal literature
- Hepatic substrate handling — glucagon-receptor contribution in isolated systems
For background reading on the underlying pharmacology, see our Research Library article on GLP-3R triple agonist metabolic research, which cites the primary literature.
Specifications
| Catalog designation | GLP-3R |
| Compound | Retatrutide (LY3437943) |
| CAS number | 2381089-83-2 |
| Molecular formula | C₂₂₁H₃₄₂N₄₆O₆₈ |
| Molecular weight | 4731.33 g/mol |
| Sequence length | 39 amino acids |
| Net peptide content | 10 mg |
| Purity | ≥99% (HPLC) |
| Identity confirmation | Mass spectrometry (LC-MS/MS) |
| Form | Lyophilized powder, sealed vial |
| Storage | −20°C, protect from light and moisture |
| Testing laboratory | Freedom Diagnostics (independent third party) |
| Country of testing | United States |
Certificate of Analysis
Every batch is third-party tested by Freedom Diagnostics for identity, purity, and net peptide content by HPLC and LC-MS/MS. The COA for the batch currently shipping is published on this page — before purchase, not after. We do not publish summary claims in place of the document itself.
Learn how to read a COA, or browse the full COA library covering every compound in the catalog.
Storage and handling
Sealed lyophilized vials are stable at −20°C when protected from light and moisture. Allow vials to reach room temperature before opening to avoid condensation drawing moisture into the powder. Handling should follow your institution’s standard procedures for laboratory peptides.
Full guidance is in our peptide storage and handling guide. Laboratory-grade bacteriostatic water and reconstitution solution are available separately.
Shipping
Orders placed before the daily cutoff ship the same business day from our United States facility. Vials ship sealed with batch documentation referenced on the packing slip.
Common questions
Is GLP-3R the same as retatrutide?
Yes. GLP-3R is our catalog designation; retatrutide (LY3437943) is the compound name assigned by its originator. The vial contains the same 39-amino-acid triple agonist described above.
Why do suppliers use different names for it?
Research chemical suppliers commonly assign internal catalog codes rather than using the originator’s development name. This is why the same molecule appears under several unrelated-looking designations. Our compound name reference lists the codes we see most often and what each one refers to.
What purity is this material?
≥99% by HPLC, with identity confirmed by mass spectrometry. The batch COA is published on this page so the figure can be verified against the chromatogram rather than taken on assertion.
Who tests it?
Freedom Diagnostics, an independent United States laboratory. Testing is not performed in-house, and the COA identifies the testing lab and batch number.
Is retatrutide approved by the FDA?
No. It is an investigational compound that has not been approved by the FDA or any other regulatory authority for any indication, in any formulation. It is supplied here for laboratory research only.
Research use only. This product is intended solely for laboratory research by qualified personnel. It is not a drug, food, cosmetic, or medical device. It is not for human or veterinary use, and must not be administered to humans or animals. Retatrutide has not been evaluated or approved by the FDA for any indication. No statement on this page is intended to characterize the safety or effectiveness of this compound for any purpose. Purchasers are responsible for handling this material in compliance with all applicable laws and institutional requirements.
