How to Read a Peptide COA

A certificate of analysis is only useful if it proves the exact batch in your hand is what the label claims, so the first thing to check is whether the report's batch number matches the vial or listing. Beyond that, look for the core tests: identity, which confirms the molecule is actually what it says; purity, which shows how much is the target compound versus impurities; net content, which is how much peptide is really present; and the contamination checks, meaning endotoxin, sterility, and heavy metals. A COA that shows only a purity number, with no identity or contamination testing, tells you far less than it appears to. The clearest weak signs are a missing batch number or an old report reused across many different listings. A report you cannot tie to your specific batch is general marketing, not evidence about your vial.