How to Read a Peptide COA Before Ordering

Why the COA matters

A Certificate of Analysis (COA) is the primary document research teams use to evaluate a peptide listing before ordering. This guide explains what to look for, section by section, and how COA transparency signals a reliable research supplier.

What to check on a COA

• Batch/lot number – matches the specific vial you’re evaluating.
• Purity (%) – measured by a stated method (e.g., HPLC), with the chromatogram available.
• Identity confirmation – mass spec or equivalent confirming the compound.
• Test date & testing party – recent, and ideally third-party.

Signals of a reliable research supplier

Batch-specific COAs (not a generic sample), transparent testing methods, consistent results across batches, and documentation you can access before purchase.