Step by step: verify a peptide COA with the issuing lab using the report number, lookup portals or email, read the confirmation, and act if no record exists.
A certificate of analysis is only evidence once the laboratory that supposedly issued it says so. Everything else, the letterhead, the purity figure, the supplier’s “third-party tested” badge, is a claim. This guide is the procedure we use to turn a claim into a checked fact, written so a buyer can follow it in ten minutes. It covers where to find the report number, how to reach the lab without going through the supplier, what to ask, what a real confirmation looks like, and what to do when the lab has no record.
Before you start: what verification can and cannot establish
Verifying with the lab answers one question: did this laboratory issue this report, for this product, on this date. A yes means the certificate is genuine. It does not mean the sample the lab tested came from the lot you are buying, that every vial matches the sample, or that the supplier’s handling since then preserved it. Those are limits of the document, and they apply to every supplier equally. Verification is the floor, not the ceiling.
Step 1: Collect the details from the certificate
Open the certificate and write down, exactly as printed:
- The laboratory name and any address, domain or contact it shows.
- The report number, sometimes labeled report ID, certificate number, sample ID or job number.
- Any secondary verification code or key printed near the report number.
- The product name as the lab wrote it.
- The lot or batch number.
- The test date and, if shown, the date the sample was received.
- The client name, if the lab printed one.
If the certificate is an image with the report number cropped off, or has no report number at all, stop. There is nothing to verify. Ask the supplier for the original PDF with the report number, and regard the listing as untested until it arrives.
Step 2: Reach the lab independently
Do not use the “verify” link on the supplier’s site. A clone store or a supplier with something to hide can point that link anywhere. Instead, search the lab’s name in a search engine and go to the lab’s own domain. Confirm the domain matches the one printed on the certificate. If the certificate shows no domain, note that as a flag and proceed with the lab’s public site.
Our explainer on testing laboratories lists the labs most often named on supplier certificates and what to look for on each lab’s site.
Step 3: Use the lab’s lookup if it has one
Some laboratories publish a self-serve verification form. Janoshik Analytical, the European lab most often named in our records under several spellings, is the clearest example: its site offers a report lookup that takes the report number, and in some cases a second code printed on the certificate, and returns the report details the lab holds. If the lab you are checking has a lookup, enter the details and compare what comes back against the certificate line by line.
A QR code on the certificate can serve the same purpose, but only if it resolves to the lab’s domain. Scan it and read the URL before trusting the page it opens. A QR code that lands on the supplier’s own domain is the supplier vouching for itself.
Step 4: If there is no lookup, email the lab
Most labs that do not offer a form will answer a short, specific email. Keep it to facts and one question. A workable template:
Subject: Report verification request, report no. [number]
I am checking a certificate of analysis that names your laboratory. It shows report number [number], product [name], lot [lot], test date [date]. Could you confirm whether this report number exists in your records and corresponds to that product, lot and date? I understand you may not be able to identify the client.
Attach the certificate as you received it. Do not ask the lab to interpret the results or comment on the supplier; labs will not do either, and it slows the reply.
Step 5: Read the confirmation carefully
A confirmation is only useful if it matches on the points that matter. Compare the lab’s answer to the certificate using this table.
| Point of comparison | Match | Mismatch means |
|---|---|---|
| Report number exists | Lab finds the number | If not found, the certificate is unsupported |
| Product name | Same peptide name as the certificate | Report belongs to a different product; the certificate was relabeled |
| Lot or batch | Same lot as the certificate and the listing | Report is real but for a different lot; it does not cover the item on sale |
| Test date | Same date as the certificate | Date was altered, or a different report’s data was pasted in |
| Results | Lab’s figures match the certificate’s figures | Results were edited after issue |
| Client | Lab may decline to say | Declining is normal; a named client that is not the supplier is a question for the supplier |
A full match on report number, product, lot, date and results verifies the certificate. A match on the number alone with a different product or lot does not; it tells you the supplier reused a real report where it did not belong. Keep the lab’s reply with the certificate.
Step 6: What to do if the lab has no record
A lab reply that the report number does not exist, or exists for a different product, is the strongest negative result a buyer can get. Handle it in this order.
- Save the lab’s reply and the certificate together, with the date and the URL where the certificate was published.
- Send both to the supplier and ask it to explain and to provide a certificate the lab will confirm. A supplier with a records problem will produce one; a supplier with a forged certificate will not.
- Check whether the same certificate appears on other storefronts. A shared document across unrelated suppliers points to a copied template.
- Do not rely on any of that supplier’s testing claims until it produces a confirmed certificate.
- Report it. We review lab correspondence sent to us; a confirmed non-match goes into the supplier’s report and, with the evidence summarized, onto the watchlist, and the supplier is given the chance to respond.
Step 7: Check the lot against the listing
Even a fully verified certificate covers only the lot on the certificate. Compare that lot number to the one on the product page or the vial you receive. Suppliers that test per lot publish a certificate for each; suppliers that test once and reuse the document publish one certificate across many lots, which a verified report does not cure. Our records track whether a supplier states that certificates are per lot, and our public COA list credits suppliers whose libraries show it.
What a well-run certificate library looks like
The verification steps above are easiest when the supplier has done its part. The features that make a library checkable are the same ones we credit in our grades:
- Every certificate is a PDF with a visible report number, not a flattened image.
- The lab’s domain is printed on the certificate and the certificate links or QR codes resolve there.
- Lot numbers on certificates match the lot numbers on listings and on shipped vials.
- Both HPLC and mass spectrometry are shown in full, with chromatogram and spectrum, which our guide on the two methods explains.
- Dates fall within a plausible window of the lot’s appearance on the site.
A supplier that meets those points has made verification a five-minute job. A supplier that meets none of them has published documents that cannot be checked, and we say so in its report rather than guessing at the reason.
Verification is tedious and almost nobody does it. That is exactly why it works: a forged or recycled certificate survives only until one buyer sends one email. Be that buyer.