Written by PX1 Research Team
PX1 chemists and research educators with hands-on experience in US-based peptide manufacturing, HPLC / mass-spectrometry lot testing, and endotoxin QC. All content is citation-backed and peer-reviewed for accuracy.
What Is GLP3-R? PX1's Retatrutide Explained (Identity, Purity, Lot Data)
Research Guide
Reviewed By
PX1 QC — Analytical Chemistry Team
Every article is reviewed by PX1's in-house analytical team for accuracy on mechanism, dosing ranges reported in the literature, and lab-handling guidance. We do not publish clinical or medical advice.
Quick answer
GLP3-R is PX1 Research's designation for retatrutide (LY-3437943). What the name means, how identity is confirmed by LC-MS, and what ships with every lot.
Key takeaways
- Chromatogram image, not just a purity number
- LC-MS mass confirmation
- Karl Fischer moisture result
- Lot number and manufacture date printed on the vial, matching the COA
Short answer
GLP3-R is retatrutide — the GLP-1 / GIP / glucagon triple agonist also designated LY-3437943. The "3" in the name refers to the three receptor pathways the molecule activates. It is a catalog designation, not a different molecule, a blend, or an analog.
Identity confirmation
Naming aside, the only thing that proves what is in a vial is mass spectrometry:
| Check | Expected result |
|---|---|
| LC-MS / MALDI-TOF mass | 4731.6 Da |
| HPLC purity | ≥99.0%, chromatogram attached |
| LAL endotoxin | Reported in EU/mg, per lot |
| Karl Fischer moisture | Within spec for lyophilized fill |
If a mass spec report does not accompany a vial sold as retatrutide, the identity is unconfirmed regardless of what the label says. Mislabeled tirzepatide (mass 4813.5 Da) is the most common substitution in this category, and the two are indistinguishable by eye.
What ships with every PX1 lot
- Chromatogram image, not just a purity number
- LC-MS mass confirmation
- LAL endotoxin result
- Karl Fischer moisture result
- Lot number and manufacture date printed on the vial, matching the COA
All current lots are published at /purity-reports.
Why the designation exists
Research catalogs commonly use internal designations for investigational compounds rather than the developer's clinical code. The practice is only a problem when a supplier uses a house name instead of disclosing the molecule. PX1 lists both: the catalog name (GLP3-R) and the compound (retatrutide, LY-3437943), on the product page and on the COA.
Next: dosage chart · reconstitution guide · buyer's checklist
Research use only. Not for human consumption. Not intended to diagnose, treat, cure, or prevent any disease.
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