How to read a Certificate of Analysis
What a COA should show, and the red flags that mean you should walk away.
What a COA is
A Certificate of Analysis, or COA, is a lab report on a specific batch of product. A good one tells you what the material actually is, how pure it is, and that it was tested by a lab that is not the seller. It is the closest thing you have to proof of what is in the vial.
What to check for
Look for a few specific things:
- Identity, usually by mass spectrometry, confirming the molecule is what the label claims.
- Purity, usually by HPLC, ideally 98 percent or higher.
- A batch or lot number that matches your vial.
- A recent date and the name of a third party lab.
- Tests for sterility or endotoxin for anything you plan to inject.
Red flags
WarningAny of these is a reason to be cautious or to walk away:
- No COA at all, or one the seller will not show you.
- A COA with no batch number, or a batch that does not match your vial.
- The lab named is the seller itself, with no independent testing.
- An image of a report with no way to verify it with the lab.
- Purity numbers that look too clean, or a document that looks edited.
When a COA cannot be traced back to a real lab and a real batch, treat it as marketing, not proof.
Last reviewed 2026-07-07. Educational information only, not medical advice.