How to Verify a Peptide COA: A Practical Guide

Certificate of Analysis (COA) documents are central to responsible peptide research. Whether you are evaluating a research peptide for laboratory use or comparing suppliers, a COA is the analytical evidence behind a product's stated identity and purity.

A verifiable COA typically names a third-party laboratory, a unique report or batch number, the testing date, the analytical method (often HPLC for purity and mass spectrometry for identity), and the measured values. Cross-checking the batch number against the laboratory that issued the report is the quickest way to spot inconsistencies.

Purity figures should be read alongside the method used. A 98% HPLC purity result means little without a matching chromatogram and, ideally, the independent lab's contact details so the result can be confirmed. Researchers should also look for sterility and endotoxin testing where relevant.

For a step-by-step walkthrough, see this explainer on how to verify a peptide COA.