Peptide COA Red Flags: Nine Checks Before You Trust One

A certificate of analysis is only worth something if someone other than the seller stands behind it and you can confirm that they do. These nine checks apply to any vendor's certificate, ours included. They are in the order that settles the question fastest: the first four can end the matter on their own.

The four that can settle it

• 1. No laboratory is named. A certificate with no issuing laboratory is the seller describing its own product. The figures on it may be accurate, but nothing independent supports them.
• 2. The laboratory cannot be found. Search the laboratory's name and address yourself, away from the vendor's site. A real laboratory has an address, a telephone number and a site of its own.
• 3. There is no way to confirm the document with the laboratory. Some laboratories offer a lookup by access code or report number; others will confirm a report by email. If there is no route at all, the certificate cannot be independently confirmed, and you should weigh it accordingly.
• 4. The laboratory's record does not match the copy you were given. Wrong product, wrong lot, or different results. This is the most serious finding on the list, because the two documents cannot both be right. Ask the vendor to explain the difference, and judge the answer on its speed and its detail. Where the two differ, the laboratory's record is the one to rely on.

The five that tell you how much the document covers

• 5. The lot number is missing, or does not match the vial. Results belong to a lot. A certificate without one, or for a different one, says nothing about the vial in front of you.
• 6. Purity is reported with no method. A percentage alone is not a result. Look for the technique (HPLC, for peptides) and the specification the figure was judged against.
• 7. Identity was not tested. Purity says how clean the sample is, not what it is. A certificate with a purity figure and no identity line has left the more basic question open.
• 8. The dates do not make sense. Check the received, tested and issued dates against each other and against when the lot was sold. A certificate dated long before the lot existed, or reused unchanged across several lots, is describing something else.
• 9. Nobody signed it. A report from a laboratory names the person responsible for it. An unsigned table of numbers is a spreadsheet.

The difference between the sixth and seventh checks is the one most often missed; it is set out in what an HPLC purity number does and doesn't prove.

What a clean result on all nine means

It means the document is what it claims to be: a real laboratory tested a sample from that lot and reported those results. It does not mean the results are good — that is a separate reading, covered in how to read a certificate of analysis. It does not cover what happened to the material after the sample was taken.

Running the checks

The full workflow, with a worked example you can run in a minute, is in how to verify a COA with the issuing laboratory. To run it on one of ours, start from any lot number on our verification page.