A Certificate of Analysis is only evidence if it can be tied to the exact batch in your hand. Much of what circulates as a “COA” is a purity number on a letterhead — real-looking, and proof of nothing. These are the checks that separate the two, and they take under a minute.
Red flags that end the conversation
- No batch number on the certificate — a purity figure with no batch linkage could describe any vial ever made, including none of yours.
- The batch number on the COA does not match the batch printed on the vial label.
- No test date, or a date long before the product could have been manufactured — “representative” reports are recycled indefinitely.
- No named laboratory and no analytical method stated (HPLC, MS). Real reports name who tested, how, and against what specification.
- The vendor will only share the COA privately (“DM us for the COA”). Documentation that hides is documentation that changes.
What a verifiable COA looks like
- Batch number on the certificate matches the vial label and the vendor's public batch register.
- Identity, purity (HPLC area%), and assay reported against a stated specification, with the method named.
- Test date consistent with the batch's manufacture and release dates.
- Independently checkable: you can reach the record from a public lookup — not only from a file the seller hands you.
Tip
Practice on a live record: every TARA vial's verify ID resolves at the public Verify page to its batch, COA, and release status — no account needed. Any vendor can be held to that standard.
If a certificate fails these checks, treat the material as undocumented: quarantine it and raise it with the seller. A missing or mismatched COA is a quality signal about everything else in that supply chain.