How to read and verify a peptide certificate of analysis (COA)
A certificate of analysis (COA) is the main evidence a supplier can give that a vial contains what the label says, at the stated purity. But a COA is only useful if it is genuine, belongs to the batch you receive and covers the right tests. This guide explains how to read one and how to check it, for laboratory purchasing decisions.
- Authentic: the report can be confirmed on the testing lab's own website or by the lab directly, not only as a PDF from the seller.
- Right batch: the lot or batch number on the COA matches the number printed on your vial.
- Right compound: mass spectrometry shows a measured mass that matches the expected molecular weight.
- Right tests: purity (HPLC) and identity (MS) at minimum; for some uses also peptide content, endotoxin and sterility.
Reading a COA field by field
| Field | What to look for | Red flag |
|---|---|---|
| Testing laboratory | A named independent lab with contact details | No lab named, or "in-house testing" only |
| Report or task number | A unique identifier you can look up with the lab | No identifier, or the same number on several products |
| Sample or lot number | Matches the lot printed on your vial | Generic "BPC-157 10 mg" with no lot, or a lot that does not match |
| Test date | Recent and consistent with the batch | Report years older than the product |
| HPLC purity | A chromatogram with a main peak and a stated % purity | Only a number, no chromatogram; every product exactly 99.9% |
| Mass spectrometry (identity) | Measured mass close to the expected molecular weight | No MS data; mass far from the expected value |
| Peptide content | Amount of actual peptide in the vial, if tested | Large difference from the labelled mg without explanation |
| Additional panels | Endotoxin, sterility, heavy metals where relevant | Claims of "sterile" or "endotoxin-free" with no test shown |
Purity is not identity
HPLC purity tells you what share of the material is one main compound. It does not tell you which compound that is. A vial could be 99% pure and still be the wrong peptide. Identity comes from mass spectrometry: the measured mass should match the expected molecular weight listed on each of our compound profiles, allowing for salt forms such as acetate.
How to verify a report with the lab
- Use the lab's own verification. Some labs, including Janoshik Analytical, print a task number and a verification key on each report so it can be checked on the lab's website. Enter those details there rather than trusting a screenshot.
- Contact the lab. If there is no online verification, email the lab with the report number and ask whether it issued that report for that sample.
- Check independent test data. Independent databases such as Finnrick publish their own purchase-and-test results for many vendors. Ratings change over time, so check the live page.
- Match the lot. Even a genuine report proves nothing about your vial if the lot number differs.
Common signs of an unreliable COA
- The same chromatogram image appears on several different products.
- The PDF has edited text, mismatched fonts or a blurred lab name.
- The supplier refuses to share the report number or lot-specific COA.
- The COA lists a different compound name or molecular weight from the product.
- Only a purity percentage is given, with no method or chromatogram.
Where this fits in supplier checks
A verified COA is one of six checks in the "Before you buy" list on every compound page. The others cover human-use marketing, FDA warning letters and buyer confirmation. See our FDA warning letters tracker and run any supplier through the vendor check.
Frequently asked questions
What is a certificate of analysis for peptides?
A lab report showing the identity, purity and sometimes the content of a specific batch of peptide, ideally from an independent third-party lab.
How do I know if a peptide COA is real?
Confirm it with the testing lab using the report number or verification key, check that the lot number matches your vial, and check that the mass spectrometry result matches the expected molecular weight.
Is HPLC purity enough?
No. HPLC shows purity but not identity. You also need mass spectrometry to confirm the compound is the right one.
Does a COA make a product safe for human use?
No. A COA is an analytical record for laboratory purposes. It does not establish that a product is suitable or legal for human use.