Nearly every peptide vendor advertises third-party testing. Far fewer can produce a certificate of analysis that survives scrutiny. This guide walks through each section of a real COA and catalogs the fabrication patterns we have documented while building our testing database.
Start with provenance: a real COA names the laboratory, carries a report number traceable with that laboratory, and is dated within a plausible window of the batch’s manufacture. The single most common fake we see is a genuine template with the compound name and purity figure edited — often leaving mismatched fonts in the results table.
The chromatogram is the heart of the document. Check that the main peak’s retention time is stated, that integration values sum plausibly, and that the stated method (column, gradient, detection wavelength) matches the compound class. A chromatogram with no axis labels or integration table is decoration, not data.
Mass-spectrometry identity data should state the expected and observed mass with the instrument identified. For modified peptides, the observed mass must reflect the modification — a surprising number of fabricated COAs list the unmodified sequence mass.
When in doubt, our testing database publishes full laboratory documentation for every specimen we test, so you can compare a vendor’s COA against an independent result for the same product line.
