A Certificate of Analysis (COA) is the single most important document when sourcing research peptides. But not all COAs are equal — some are genuine batch-specific lab reports, others are reused or fabricated. This guide explains how to read one and what separates real documentation from a red flag.
What a real COA contains
- Lot / batch number that matches the number on your vial.
- HPLC purity result — typically expressed as a percentage, ideally with the chromatogram.
- Mass-spectrometry (LC-MS) identity confirmation verifying the compound is what it claims to be.
- Analysis date and the name of the testing laboratory.
- Additional tests such as endotoxin, residual solvents, and water content.
Real vs. fake: the quick checklist
| Signal | Real COA | Red flag |
|---|---|---|
| Lot number | Matches your vial | Missing or generic |
| Testing | HPLC + LC-MS shown | Vague “lab tested” claim only |
| Documentation | Batch-specific | Same PDF reused on every product |
| Lab | Named, dated | No lab, no date |
Why batch-specific matters
Peptide quality varies by production lot. A COA that is not tied to the specific batch you receive tells you nothing about your actual vial. If a supplier cannot produce a COA that matches your lot number, treat that as a failure regardless of marketing claims.
How Greatest Peptides documents quality
Every order includes batch-specific COA documentation for the exact lot shipped, with HPLC purity and LC-MS identity confirmation. Review our third-party testing or browse the research peptide catalog.
For laboratory and research use only. Not for human or animal consumption.