This page is about documentation and red flags — what makes a sourcing claim actually checkable versus just a number on a product page. Nothing here is about dosing or which vendor to use.
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Get my free report + free book →A Certificate of Analysis is a lab report for a specific batch — it typically shows purity (often by HPLC, high-performance liquid chromatography), and sometimes mass spectrometry confirmation of the compound's identity. A real CoA is traceable: it names the testing lab, references a batch or lot number that matches what's on the product you actually received, and is dated close to when that batch was produced. A CoA that's generic, undated, unmatched to a lot number, or hosted only as a screenshot with no way to verify against the issuing lab is not doing the job a CoA is supposed to do.
"Third-party tested" means an independent lab — one with no financial relationship to the vendor — ran the analysis. In-house testing, or testing by a lab the vendor owns or has an undisclosed relationship with, is a real conflict of interest, even when the vendor is being honest about the results. A credible vendor names the testing lab and makes it possible to confirm that lab actually exists and actually does this kind of testing.
This is counterintuitive but worth internalizing: a vendor that clearly, consistently labels its products "for research use only, not for human consumption" is being accurate about the legal status of what it sells (see our legal status guide). A vendor that avoids that labeling, or buries it while marketing directly to personal use, is being less honest about the actual regulatory reality — which should raise more concern about everything else the vendor claims, not less.
A few patterns show up repeatedly among less credible sourcing operations: pricing dramatically below the rest of the market with no explanation; marketing copy that makes specific health-outcome claims (a legitimate RUO vendor generally won't, because doing so undercuts the RUO labeling); no verifiable business address or manufacturing information; purity claims with no accompanying CoA at all; and customer-service channels that only exist through anonymous messaging apps rather than any traceable business entity.
This isn't a list of recommended vendors, and it isn't dosing or usage guidance. It's a way to evaluate whether a sourcing claim you're looking at is actually verifiable. For the bigger regulatory picture these claims sit inside, see are research peptides legal.
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