How to Read a Certificate of Analysis

A Certificate of Analysis (COA) is the document that stands between a researcher and an unverified white powder. Issued by the laboratory that tested a specific production lot, it records what the material is, how pure it is, and when and how that was established. For research materials sold without pharmaceutical oversight, the COA is effectively the only objective evidence of quality a buyer ever sees — which is why we publish one for every lot in our COA library before it ships.

Product identity and lot number. The header should name the exact compound and strength, and — critically — a lot (batch) number that matches the label on the vial you received. A COA without a lot number is a brochure, not a certificate: it cannot be tied to any physical material.

Test date and laboratory. A legitimate certificate names the testing lab and the date of analysis. Third-party testing (a lab independent of the seller) carries more weight than in-house numbers, because the tester has no stake in the result.

HPLC purity. The centerpiece is a chromatogram from high-performance liquid chromatography with a purity percentage — the fraction of the total peak area belonging to the target compound. The measured value for each lot is on its certificate; the HPLC explainer covers how that number is actually computed.

Identity confirmation. Purity alone says 'this sample is 99% one thing'; mass spectrometry (MS) confirms that the one thing has the correct molecular weight for the labeled peptide. Look for an observed mass alongside the theoretical mass.

Appearance and physical checks. Lyophilized peptides are typically described as a white to off-white powder or cake. Gross deviations (discoloration, oiliness) are themselves a failure mode worth catching.

Be skeptical of certificates that are undated or years old, that lack a lot number, that name no laboratory, or that appear as low-resolution images recycled across many products. A vendor who tests every lot can always show you a current document for the exact batch in your hands — and a vendor who cannot, cannot.

Every product page on this site links the current lot's certificate directly, and the full archive is browsable in the COA library. If you ever receive a vial whose lot number has no matching certificate, contact us — under our refund policy, a COA mismatch is grounds for replacement or refund.