How to Read a Peptide Certificate of Analysis (COA)

A Certificate of Analysis (COA) is the single most important document you should review before using any research peptide. It is the independent verification that what is in the vial matches what is on the label — and that it meets the purity threshold required for reliable research.

What a COA Should Include

A legitimate COA will contain the following:

Identity Confirmation — typically via Mass Spectrometry (MS), confirming the molecular weight matches the target peptide sequence.

Purity Assessment — typically via High-Performance Liquid Chromatography (HPLC), expressed as a percentage. For research-grade peptides, 98%+ is considered acceptable; 99%+ is the standard Peptagon holds all products to.

Appearance — a physical description of the lyophilized powder, confirming it is white to off-white and free of visible contaminants.

Lot Number — linking the COA to a specific production batch, allowing full traceability.

Red Flags to Watch For

Be cautious of COAs that are undated, lack a lot number, or come from an in-house lab rather than an independent third-party facility. At Peptagon, all testing is conducted by independent laboratories with no affiliation to our synthesis process.

Accessing Your COA

Every Peptagon order ships with a QR code linking directly to the COA for that specific batch. You can also access all COAs directly on our website.