How to Verify a Peptide COA

The eight-step verification

1. 1

   Identify who issued the report

   Look for the laboratory's legal name, physical address, and a report or reference number in the header. A COA with only a logo, or one hosted solely on the seller's own website with no lab identity, is a marketing document rather than a certificate of analysis.

2. 2

   Match the lot number to the vial

   The batch or lot number on the COA must match the number printed on the vial or pouch you received. A mismatch means the report describes a different batch, and a batch that tested at 99% tells you nothing about the batch in your hand.

3. 3

   Check the test date against your purchase

   Compare the analysis date to when the material was manufactured and shipped. Reports dated years before the batch, or reused across many batches with the same date, indicate a template rather than a fresh analysis.

4. 4

   Confirm raw data is attached

   A legitimate purity report includes the integrated HPLC chromatogram with retention times and peak areas, plus the mass spectrum or LC-MS trace confirming identity. Without those, the percentage on the page cannot be checked by anyone.

5. 5

   Read the method section

   The report should state the technique (reverse-phase HPLC with UV detection), the detection wavelength (typically 214 nm for peptide bonds), the column, and the gradient. Purity reported with no wavelength is not comparable to any other result.

6. 6

   Look for internal inconsistencies

   Check that the peak areas in the chromatogram actually sum to the stated purity, that the reported mass matches the theoretical monoisotopic mass of the sequence, and that fonts and alignment are consistent. Edited PDFs commonly show mismatched fonts in the purity field.

7. 7

   Contact the issuing laboratory

   Email or call the lab named on the report with the report number and ask them to confirm they issued it. Most labs will verify or deny a report number for a third party. A lab that has no record of the number is the clearest possible answer.

8. 8

   Re-test independently when the stakes justify it

   Document review can catch fabrication, but it cannot confirm what is in the vial. Sending a sample to an unaffiliated laboratory under a blind or coded submission is the only way to independently establish purity and identity for the material you actually hold.

What each field on the report should show

Signs a report checks out

• The lab confirms the report number when you contact them.
• Lot number on the report matches the marking on the vial.
• Chromatogram is attached and its peak areas support the stated purity.
• Observed mass matches the theoretical mass for the sequence.
• Method, column, and detection wavelength are all named.

Signs to treat the number as unverified

• No chromatogram, only a purity percentage on a branded page.
• Lot number missing, or different from the vial.
• The same analysis date appears across unrelated batches.
• No detection wavelength and no named method.
• The laboratory has no record of the report number.
• Fonts or alignment in the purity field differ from the rest of the table.

When document review is not enough

Every check above examines a document. None of them examine the vial. A report can be genuine, correctly issued, and still describe a batch that was blended, stored badly, or repackaged after testing. When the answer matters, the resolution is an independent test on the material in front of you. ACS Peptide Testing Labs is an independent laboratory in Sun City Center, Florida with no supplier affiliation, and every report ships with the integrated chromatogram and identity spectrum. See HPLC purity testing, mass spectrometry identity confirmation, and blind peptide testing with coded submission. Published outcomes across past samples are on the verified peptide test results page, and pricing is in the peptide purity testing cost guide.

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