Certificate of Analysis, or COA, is the single most important document in this entire market, and it’s also the most commonly misunderstood or faked. Here’s the plain-language version.
What a COA Actually Is
A COA is a lab report confirming what’s actually in a specific vial — typically purity percentage and, ideally, confirmation of the correct amino acid sequence, not just an overall purity number. It should be generated by a lab, ideally an independent third party rather than the vendor’s own in-house testing.
The Question That Actually Matters: Is It Batch-Specific?
A generic COA representing “a” sample of a peptide is far less meaningful than one matching the exact lot or batch number printed on the vial you’re about to receive. Ask the vendor directly whether the COA they display corresponds to your specific shipment’s batch, and expect a clear answer.
What Purity Percentage Does and Doesn’t Tell You
A 98% purity figure describes how much of the tested sample is the intended compound versus impurities — but it doesn’t by itself confirm the amino acid sequence is fully correct and complete. A truncated sequence can still register a high purity percentage while not being the fully active compound. Sequence confirmation (often via mass spectrometry) is the more complete verification.
A Simple Pre-Purchase Checklist
- Is there a COA at all, or just a purity claim on packaging?
- Is the COA batch-specific and does the vendor confirm it matches your shipment?
- Was it generated by an independent third-party lab?
- Does it include sequence confirmation, not just purity percentage?
- Is the manufacture and testing date recent relative to your purchase?