A certificate of analysis (COA) is the document that tells you what's actually in a vial. Knowing how to read one is the difference between trusting a label and verifying it.
Identity
Confirms the compound matches what's advertised, often via mass spectrometry. The measured mass should match the expected molecular weight.
Purity
Usually reported as a percentage from HPLC analysis. A higher percentage means fewer impurities — look for the method and the chromatogram, not just a number.
Lot number
Ties the document to the exact batch you received, so results are traceable and reproducible.
This article is educational and is not product guidance or medical advice. All products are sold for research use only and are not for human or veterinary consumption.