QA-04Updated 2026-05-19
How do I read a Certificate of Analysis (COA) for a research peptide?
A COA is the lab report for a specific batch. Verify the batch number matches your vial, check HPLC purity is ≥99%, confirm mass-spec molecular weight matches the target sequence, and confirm the report was issued by an independent accredited laboratory.
A Certificate of Analysis is the most important document you receive with a research peptide. Read it like a scientist, not a customer.
What to verify on every COA:
- Batch number matches your vial. A COA for a different batch is no COA at all.
- HPLC purity ≥99.0%. Below that is research-grade in name only.
- Mass spectrometry confirms the correct molecular weight for the target sequence. This proves the molecule in the vial is what was ordered.
- Issuing laboratory. A serious supplier names an accredited, independent lab — not "internal QC."
- Date and sample identity — the report should reference the same SKU and lot you purchased.
If a supplier resists providing a COA, supplies a generic one with no batch number, or only offers internal QC reports, treat it as a red flag.
Learn more in our supplier-vetting primer.