Peptide COA Red Flags: A 10-Point Checklist

A certificate of analysis (COA) is only useful if it is complete, consistent and traceable. This checklist lists ten things that should make you slow down and ask questions before relying on a report. None of them proves a report is wrong on its own; together they show how much weight it deserves.

The ten red flags

1. No lot or batch number. A COA describes one lot. Without a lot number you cannot tie the report to the vial in your hands. See how to verify a peptide COA.
2. No laboratory name or contact details. The report should say which laboratory ran the tests, with an address or website you can find independently, not only through the seller.
3. No test date, or a date that does not fit. A test date well before the lot could have been made, or none at all, is worth a question.
4. A report that looks edited. Mismatched fonts, uneven spacing, pasted-in numbers or a different layout from the same laboratory’s other reports can mean the document was altered. Compare it with other reports from the same lab.
5. A chromatogram that is missing, cropped or unlabeled. For HPLC purity, the trace behind the percentage should be shown, with labeled axes and the main peak identified. A bare number with no trace cannot be checked. See how purity is tested.
6. Purity with no identity test. HPLC tells you how much of the detected material is one peak; it does not by itself prove that peak is the intended molecule. Look for a mass spectrometry (identity) result alongside it.
7. Numbers that do not add up. Peptide plus excipient mass should be close to the stated total mass, and the ratio line should match. See the peptide-to-excipient ratio guide.
8. Purity treated as potency. A 99%+ purity figure says nothing about how much peptide is in the vial. If a report or seller uses one to imply the other, read purity vs. potency.
9. Identical results across different products. The same purity, mass and chromatogram appearing on different compounds or lots is a strong reason to ask the laboratory directly.
10. A report you cannot verify. If the laboratory has no QR code or verification link, and will not confirm the report number when asked, treat the report as unconfirmed.

What to do if you find one

Note it, ask the seller and the laboratory for clarification in writing, and hold off on relying on the lot until you have an answer.

See it on real reports

Each HLX Peptide certificate is published on our COA page, with the lot, laboratory, test date and HPLC purity listed beside the full PDF. More on our Quality & Testing page, and general reading help in how to read a peptide COA. For what independent testing should mean, see is peptide lab testing really independent? Browse all products.

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