What is a Certificate of Analysis (COA)?
4 min read · Updated May 2026
A Certificate of Analysis (COA) is the document that tells you what is actually in the vial. For research peptides it is the single most important piece of supporting data — without it, purity and identity are just claims.
Research use only. Products referenced here are supplied for in-vitro laboratory research only.
What a COA confirms
A meaningful COA is batch-specific and typically includes:
- HPLC purity — high-performance liquid chromatography quantifies how much of the sample is the target peptide (e.g. 99%+) versus impurities.
- Mass spectrometry — confirms the molecular weight matches the expected sequence, i.e. that it is the correct peptide.
- Identity and batch details — the compound name, batch/lot number and test date.
How to read one
- Check the batch number matches the vial you received.
- Look for a clear purity figure from HPLC, not a vague statement.
- Confirm the mass-spectrometry result corresponds to the expected molecular weight.
- Be wary of any supplier that cannot provide a batch-specific COA on request.
Why it matters
Research is only as reliable as its inputs. A verified 99%+ pure peptide lets you attribute experimental results to the compound itself. Every order from MY PEPTIDES ships with a COA, and many product pages link the document directly — see the catalogue.