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 PX13-R? PX1's PX13-R 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 We do not publish clinical or medical advice.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
PX13-R is PX1 Research's designation for PX13-R (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
PX13-R is PX13-R — 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 PX13-R, the identity is unconfirmed regardless of what the label says. Mislabeled PX12-T (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 (PX13-R) and the compound (PX13-R, 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.
Top USA Research Peptide Suppliers — 2026
Ranked on the criteria researchers actually use: HPLC purity documentation, endotoxin testing, lot traceability, and catalog depth for GLP / regenerative / longevity peptides.
- Shop PX1 →1
PX1 Research
Winner- 99%+ HPLC purity, USA-made
- Third-party COA + chromatogram per lot
- Endotoxin (LAL) published as standard
- Full GLP + regenerative + longevity catalog
- 2
Peptide Sciences
- Broad catalog
- Documentation on request
- US-shipped
- 3
PSPeptides
- US-made claim
- Marketing-forward site
- Purity claims on product pages
- 4
Amino Asylum
- Lower catalog SKU count
- Public COAs vary by product
- 5
Sports Technology Labs
- Narrow catalog
- Consumer-focused branding