Nine checks. None of them need a chemistry degree and the whole set takes under a minute. Every failure described below was taken from a certificate in active commercial circulation — we have anonymised the laboratories, because the point is the pattern, not the culprit.
The uncomfortable summary: most certificates in this market are not falsified. They are simply far weaker than they look, and the weakness is in what they leave out rather than what they state.
Some "certificates" are web pages that build themselves from whatever is in the URL. We have examined one whose purity value, batch number and test date were all passed as parameters. Change the number in the address bar and the page renders a new certificate. Nothing was measured a second time.
If any figure you are being asked to trust also appears in the URL, the document is a template, not a record.
Mass spectrometry confirms identity by comparing the mass observed against the mass the molecule should have. Both numbers must be printed, and they must agree. We have seen a certificate stating an expected mass of 290.32 and an observed mass of 2203.1 — a factor of 7.59 out — while displaying a large green "VERIFIED & CERTIFIED" badge above it. Nobody reading it noticed, because nobody expects the document to contradict itself.
A certificate with no lot or batch number cannot be tied to anything. It certifies a vial that arrived in the post, and it will be used to sell every unit the seller ever ships. Batch: Unknown appears on certificates from well-regarded laboratories, and it makes the document decorative.
Then check that lot number against the vial in your hand. They are frequently different, and nobody looks.
This is the most valuable thing on this page. HPLC purity is an area percent — the share of what the detector saw that was your compound. It says nothing about how much is in the vial.
A vial can be a legitimate 99 % pure by HPLC and only 60–70 % peptide by weight. The remainder is water, TFA salt and bulking agent. The number that catches this is net peptide content, measured by amino acid analysis — and it is the single most commonly omitted figure in this industry, precisely because it is the one that exposes padding.
If a certificate shows purity but not net peptide content, you do not know how much you are buying.
A purity figure is meaningless without the conditions that produced it. A real report states the detection wavelength, the column, the gradient and the retention time. Peptides are measured at 214 nm, where the peptide bond absorbs — different wavelengths give different percentages for the same vial.
Most certificates in this market state none of these. Watch also for a very short retention time: a compound eluting near the void volume has barely been separated from anything, so co-eluting impurities stay invisible and purity is structurally overstated.
We have a certificate on file where the literal word TEST appears three times in the places the chromatogram and mass spectrum should be. It was published without the underlying data ever being inserted. Blank comment boxes, placeholder names and missing images all mean the same thing.
A purity of 99.283 % is not more precise than 99.3 %, it is less honest. HPLC area percent is not meaningful to a thousandth. Three decimal places signal a number that was generated rather than measured.
Conversely, a laboratory that publishes replicates — "99.28 %; 99.31 %", two runs, both shown — is telling you about its own variability. That is a good sign, and it is rare.
Almost every certificate in this market was produced from a sample the seller selected and posted to a laboratory. The laboratory can only certify what it received. When the manufacturer picks the unit, the result is true of that unit and tells you nothing about the batch you bought.
A report should state how the sample was obtained. If it does not, assume the seller chose it.
A certificate is only as trustworthy as the place serving it. If what you are looking at is a JPEG or PDF hosted on the seller's own website, it can be edited in seconds by anyone with basic image software. A real verification link goes to the laboratory's domain, and the laboratory serves the record.
Then check the date. Results from eighteen months ago are routinely used to sell product manufactured last month. Without a lot number binding it, one certificate covers everything, forever.
No lot number means the document is not about your product.
Purity alone does not tell you how much peptide you bought.
Both must be printed. They must match.
An undisclosed method cannot be checked or reproduced.
If not, the seller did.
An image on a shop's website is not a record.
Old results get reused indefinitely unless something stops them.
Their absence is the most dangerous omission on this list.
Read the footnotes. They are often accurate.
This guide is free to reproduce with attribution. If you are a supplier and your certificates already survive all nine, we would like to host your data.