How to read a certificate of analysis (CoA)

A trustworthy CoA names the lab, the lot, the measured purity and the method, and can be verified at source. Here's what to check.

Named, independent lab

A named third-party lab must appear (e.g. Janoshik). A CoA with no identifiable lab is not verifiable.

Lot and date

The certificate must map to a specific lot and a recent date. A generic or old CoA does not vouch for the vial you buy.

Purity and method

Look for the purity percentage and the method (HPLC, mass spectrometry). Without a stated method the number is not interpretable.

Verify at source

The best CoAs link to the lab's own page (e.g. verify.janoshik.com) where the report is confirmed with a hash. That blocks forgeries.