What to Look For in a Certificate of Analysis
A COA is only useful if you know what to check. A short guide for buyers.
A certificate of analysis (COA) reports the results of testing on a specific batch against its specification. It should identify the product, batch number, manufacturing and expiry dates, and the specification each result is measured against.
Check that the tests match what matters for the product: identity, assay or standardisation, microbiology, heavy metals and, for botanicals, residual solvents or pesticides where relevant. Each result should state its method and limit.
Ask whether results come from in-house or independent laboratories. For high-value or sensitive materials, independent verification of a sample batch is a reasonable request.
Finally, compare the COA with the technical data sheet. The TDS describes what the product is meant to be; the COA confirms what this batch actually is.
