How to Read a Certificate of Analysis (COA) for Research Peptides
A COA is the most important document for verifying peptide quality and purity. Here's exactly what to look for — and the red flags that indicate a product isn't research-grade.
A Certificate of Analysis (COA) is a third-party laboratory document that confirms the identity, purity, and quality of a compound. For research peptides, it is the primary evidence that a product is what the supplier claims — and that it is safe for laboratory use.
What a COA Must Include
A legitimate COA for research peptides should contain:
1. Identity Confirmation
The compound must be verified as the peptide claimed. Common methods include:
- ·Mass Spectrometry (MS) — confirms the molecular weight of the peptide, which is unique to its amino acid sequence
- ·HPLC-MS — combines chromatographic separation with mass confirmation for highest confidence
2. Purity Percentage
Reported as a percentage, typically measured by HPLC (High Performance Liquid Chromatography). Research-grade peptides should meet the following minimums:
| Grade | Minimum Purity |
|---|---|
| Research grade | ≥ 95% |
| High-purity research | ≥ 98% |
| Pharmaceutical reference | ≥ 99% |
Impurities in peptide synthesis include truncated sequences, deletion sequences, and oxidation products. Lower purity means more of these contaminants in every dose.
3. Third-Party Testing
The COA should be issued by an independent laboratory — not the supplier's internal lab. Look for the lab name, address, and report number. Common reputable testing labs include Janssen, Eurofins, and university-affiliated analytical chemistry departments.
4. Lot or Batch Number
The COA must reference the specific lot or batch of product you received. A COA for a different batch is not evidence that your batch is pure.
5. Date of Analysis
Testing should be recent — within the last 12–24 months. Peptide purity can degrade over time, particularly if storage conditions are suboptimal.
Red Flags to Watch For
- ·No third-party lab name — internal testing is not independently verified
- ·Purity below 95% — unacceptable for research use
- ·No mass spec data — HPLC alone cannot confirm identity, only relative purity
- ·Generic batch numbers — "Batch 001" repeated across multiple products suggests copy-paste documentation
- ·COA not matched to lot number on your vial
- ·Molecular weight not listed — a critical identifier for any peptide
How to Verify a COA
Some suppliers provide QR codes or direct links to laboratory portals where you can independently pull the COA from the testing lab's system. This is the gold standard. When in doubt:
1. Note the lab name on the COA
2. Search the lab's website or contact them directly
3. Provide the report number to confirm authenticity
Why It Matters
Research integrity depends on compound quality. Impure or mislabeled peptides produce unreliable results, make data unreproducible, and can invalidate entire experimental series. Demanding a COA — and knowing how to read it — is a basic competency for any serious researcher sourcing compounds externally.
All JA Performance peptides ship with third-party HPLC-MS COAs verified by independent laboratories. COAs are available on every product page.
Browse the full peptide catalogue or visit the FAQ for common questions about storage, reconstitution, and shipping.
Note: All peptides are sold strictly for in vitro and laboratory research purposes.