What a COA Is
A Certificate of Analysis is a document that summarizes the analytical results for a specific lot. It typically includes lot number, manufacture or assay date, the test methods used (e.g., HPLC, MS), the result (e.g., 99.2% purity, identity confirmed), and recommended storage. A COA is the receipt of characterization.
Who Issues a COA
A COA can be issued by the manufacturer's in-house QC laboratory or by an independent third-party laboratory. Both are valid documents, but they answer different questions. An in-house COA tells you what the manufacturer measured; a third-party COA tells you what an independent lab measured.
Why Third-Party Testing Adds Value
Independent verification reduces the risk of self-reporting errors. A separate laboratory uses different instruments, different operators, and often different methods. When the third-party result agrees with the in-house result, confidence in the lot increases substantially.
What to Look For
When evaluating a research peptide supplier, look for: a per-lot COA shipped with the product, clear identification of which laboratory performed the assay, and a stated purity threshold (e.g., ≥99% by HPLC). For high-stakes research, third-party verification is the stronger signal.
This article is educational reference content. All products discussed are sold strictly for in-vitro laboratory research. Not for human consumption. Not approved by the FDA. Not intended to diagnose, treat, cure, or prevent any disease.