TL;DR: A Certificate of Analysis (COA) is the lab report behind a supplement batch. Check four things: who ran the test, what was tested, the batch it applies to, and whether the results match the label.
What is a COA?
A Certificate of Analysis is a document issued after a laboratory tests a specific production lot of a product. It reports what the lab measured — typically identity (is it the right ingredient?), potency (how much is actually in there?) and purity (heavy metals, and where relevant, microbial screening).
The four things to check
- The laboratory. An independent, third-party lab is the standard. A COA issued by the seller itself carries less weight than one from an outside laboratory.
- The lot number. A COA applies to one production batch. It should match the lot number printed on your bottle — a generic COA with no lot number tells you very little.
- The tests performed. Look for identity, potency and heavy-metal results at minimum. Testing scope varies by product type; the certificate should list exactly which assays were run.
- Label agreement. The measured potency should support the amount claimed on the Supplement Facts panel.
What a COA is not
A COA is evidence of quality and consistency for that batch. It is not a health claim, not an endorsement, and not a guarantee of individual results.
How this works at WQ
Every WQ production lot is tested by an independent laboratory before release, and certificates are published on our COA Lookup page — searchable by the lot number on your bottle. Our full approach is documented in the Testing Policy.
These statements have not been evaluated by the Food and Drug Administration. Our products are not intended to diagnose, treat, cure, or prevent any disease.
