How to read a peptide COA

1. Who performed the test

Check whether the report names the laboratory and whether it is the seller, the manufacturer or an independent lab. A COA should never be presented as testing by a party that didn't perform it. On our site, every supplier-provided report is labeled as supplier-provided.

2. Report ID and test date

A report ID lets a document be referenced and traced. The test date shows how recent the analysis is. Missing or reused IDs are a reason to ask questions.

3. Lot or batch number

A COA describes one production lot. It is most useful when its lot number matches the lot you receive. A report that covers a compound in general, without a lot, tells you less about a specific pack.

4. HPLC purity

High-performance liquid chromatography (HPLC) separates a sample into components. The purity figure is the share of the main peak. Look for the chromatogram itself, the method conditions and the detection wavelength — a number on its own can't be checked.

5. Identity testing (mass spectrometry)

Purity says how much of the sample is one component; identity testing (often mass spectrometry) confirms that component is the expected molecule. Both matter.

6. Signatures and original files

A signed original report or PDF from the lab is stronger evidence than a summary table. When in doubt, request the original document.

Checklist

• Laboratory named, and who it is relative to the seller
• Unique report ID and a test date
• Lot number that matches your material
• HPLC chromatogram and method, not just a percentage
• Identity confirmation (e.g. mass spectrometry)
• Signed original document available

Search our available supplier-provided records in the Certificates of Analysis database. Products without a record are marked "Documentation Pending."