What is a Certificate of Analysis (COA)?
4 min read · Updated May 2026 · MY PEPTIDES Research Team
Key facts
A Certificate of Analysis (COA) is the document that states what is actually in the vial — for research peptides, the single most important piece of supporting data, since without it purity and identity are only claims. A meaningful COA is batch-specific and typically reports HPLC purity, where high-performance liquid chromatography quantifies how much of the sample is the target peptide (for example 99%+) versus impurities; a mass-spectrometry result confirming the molecular weight matches the expected sequence, and therefore the correct peptide; and identity details including the compound name, batch or lot number and test date. To read one, check that the batch number matches the vial received, look for a clear HPLC purity figure rather than a vague statement, and 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. The products referenced are supplied for in-vitro laboratory research use only.
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.
Related reading
BPC-157
Available now from MY PEPTIDES — 99%+ purity, COA with every order, fast UK dispatch.
Frequently asked questions
- What is a Certificate of Analysis?
- A batch-specific document confirming a peptide’s purity (by HPLC) and identity (by mass spectrometry). Every MY PEPTIDES order ships with one. For research use only.
- Are your peptides third-party tested?
- Every product ships with a Certificate of Analysis including HPLC purity data and mass-spectrometry confirmation of identity.