A build is a record, so it can be audited
A single certificate is a snapshot from one laboratory, for one sample, at one moment. Gathering the certificate, the instrument data behind it, the laboratory's identity and the lot match turns the snapshot into something closer to a file. A file has an advantage a snapshot lacks: its parts can be compared with each other, and a forged or recycled document tends to contradict itself.
There is no central registry that certifies peptide sellers the way a pharmacy is licensed to dispense an authorised medicine. In that gap, internal consistency is the cheapest available test. It costs nothing, needs no special equipment, and catches a surprising share of weak documents.
Five consistency checks
- The lot agrees everywhere.The same lot number should appear on the certificate header, on the chromatogram and spectrum pages if they are labelled, and on the vial. A different string on any one of them breaks the chain.
- The dates run in a plausible order.Production or synthesis date, sample date, analysis date and report date should follow each other. A report dated before the material existed is a defect in the document.
- The mass in the spectrum fits the stated molecule.The molecular weight in the header gives the expected ions, and the spectrum should show them. The next section works through the arithmetic.
- The purity figure matches the chromatogram.HPLC purity is the share of the main peak in the total peak area. A stated 99% beside a chart with large secondary peaks does not add up.
- The laboratory can be found.The named lab should be traceable to an accreditation body's public directory, and the scope of its accreditation should cover the kind of testing reported.
Worked example: checking the mass
Electrospray LC-MS usually shows a peptide as several charge states at once. The observed value is m/z = (M + z × 1.00728) / z, where M is the neutral mass, z the charge and 1.00728 the proton mass in daltons.
[M+H]+ appears near 1,001.01. [M+2H]2+ appears near 501.01, since (1,000.00 + 2.01) / 2 = 501.01. [M+3H]3+ appears near 334.34. If a certificate states this molecular weight but the spectrum shows peaks that fit a mass 16 Da higher, a common sign of oxidation, or a different mass altogether, the identity claim has a problem.
The numbers are illustrative, not a real compound. The point is that anyone with a calculator can test whether the printed spectrum is compatible with the printed formula, without trusting the issuer.
What a build still cannot show
Consistency does not prove representativeness. A laboratory tests the sample it receives, and the build says nothing about whether that sample was drawn from the lot in your hand. Purity is also not content: a pure peptide can still be a minority of what is in the vial once water and counter-ions are counted, which is why Karl Fischer water content belongs in a complete record. Endotoxin matters wherever material contacts cells or tissue.
Screenshots with no laboratory named. A lot number that appears nowhere on the vial. A purity figure with no chromatogram. A laboratory that cannot be found. The same document reused across unrelated listings.
Regulatory status: UK and Ireland
No build changes the legal status of what it describes. That is set by the competent authorities.
Medicines for human use need a marketing authorisation under the Human Medicines Regulations 2012. Peptides sold as laboratory research materials hold none.
The Health Products Regulatory Authority is the competent authority for medicinal products in Ireland, within the EU framework. Research-grade peptides supplied outside it hold no marketing authorisation.
A build is a laboratory record and not a licence. For a health decision, speak to a licensed physician. Get the COA does not sell products, give dosing or administration information, or provide medical, legal or purchasing advice.
Sources: MHRA · Human Medicines Regulations 2012 · HPRA · ILAC on accreditation. Information only. Updated 6 November 2026.