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What to Actually Check Before Trusting a Vendor's COA

Published October 2026 · 8 min read

Every vendor in this space says "third-party tested." Almost none of them make it easy to verify what that actually means. Here's a practical checklist for telling a genuinely documented supplier from one that's just checking a marketing box.

1. Is the COA batch-specific, or generic?

The single biggest tell. A real testing program produces a new COA for every batch that comes in, tied to a lot number. If every size and every restock of a product links to the exact same PDF regardless of when you order, that document is describing a batch that may not be the one you're receiving.

2. Can you find the testing lab, and does it exist?

"Independently tested" with no lab named is not verifiable. Look for the actual lab name on the COA itself, and check that it's a real, findable analytical lab — not just initials or a generic stamp.

3. Does the COA show both identity and purity testing?

As covered in our HPLC vs. LC-MS piece, a purity percentage alone doesn't confirm identity. Look for both pieces of data, ideally from two distinct methods.

4. Is there a library, or just product-page PDFs?

Some vendors maintain a browsable, lot-searchable archive of every COA they've ever issued — not just whatever's currently linked on the product page. That's a meaningfully higher bar, because it means old batches stay auditable even after they've sold out, instead of quietly disappearing. DAAVY Research is one supplier that runs their documentation this way — every product links out to a dedicated, lot-specific COA in a standing library rather than a single static file.

5. Does the vendor disclose their actual business identity?

A legitimate operation will name its legal entity, state of registration, and a real contact method somewhere on the site — usually in a policies or footer section. A site that's cagey about who's actually behind it, with no verifiable business registration anywhere, is a site you have no real recourse with if something goes wrong.

6. Are shipping and return policies actually written out?

Vague "contact us for returns" language with no specifics on timeframes, conditions, or process is a weaker signal than a fully written policy page covering processing time, carrier, lost-package handling, and return eligibility in detail.

The pattern to watch for: transparency tends to come as a package. A vendor that's genuinely rigorous about COA documentation is usually also the one with a real policies page, a named legal entity, and clear contact information — because the same operational discipline shows up everywhere, not just on the page you're most likely to scrutinize.

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