How to Read a Peptide COA: A 5-Minute Guide for Researchers
Research peptides are only as reliable as their Certificate of Analysis (COA). If you're working with GLP-1 agonists like Retatrutide or Tirzepatide, knowing how to read a COA is essential for ensuring batch-to-batch consistency.
Here's a 5-minute guide to what matters most.
What is a COA?
A Certificate of Analysis is a document from the manufacturer that confirms the purity, identity, and quality of a specific batch. For research peptides, the COA is your primary quality assurance.
5 Things to Look for on Every COA
1. Purity (≥99% by HPLC)
High-performance liquid chromatography (HPLC) is the gold standard. Look for ≥99%. Anything lower introduces variables you don't want in your research.
*Example: Our Retatrutide batch shows 99.2% purity.*
2. HPLC Chromatogram
A real COA includes the actual chromatogram—a graph showing the purity peak. If it's missing, that's a red flag.
3. Batch Number
Batch-specific COAs matter. A "representative" COA tells you nothing about the vial in your hand.
4. Water Content (≤1%)
Peptides are hygroscopic. High water content (>1%) accelerates degradation.
5. Storage Condition
Most research peptides require -20°C storage. The COA should state this clearly.
Real Example: Retatrutide COA
This batch shows:
- Purity: 99.2% by HPLC
- Water content: 0.35%
- Storage: -20°C
## Red Flags: When to Walk Away
- No COA provided
- "Representative" COA only (not batch-specific)
- Handwritten or unreadable documents
- Missing chromatogram
## Verify COA for Our Products
We publish batch-specific COA images for every product. Visit our [COA Verification Center](/pages/coa-verification) to view purity reports.
## FAQ
**Q: Can I see a COA before ordering?**
A: Yes. Contact us and we'll send the batch-specific COA for any product.
**Q: Do you use third-party testing?**
A: We test in-house with HPLC and can provide third-party verification upon request.
