How to verify a peptide certificate of analysis

How to check that a peptide lab report is genuine, is about the lot in your hand, and comes from a lab whose accreditation you can confirm, with worked examples for TP-RTA-3, GHK-Cu and kisspeptin-10.

By Touchstone PeptidesSeptember 22, 2026Updated November 3, 20269 minute read

Checking a peptide lab report: lookups, registers and ISO 17025. Check one: Report number; Check two: Lot number; Check three: ISO/IEC 17025 register.

To verify a peptide certificate of analysis, make three checks from outside the document. Confirm with the issuing laboratory that it issued that report number with those figures; match the lot number on the report to the lot printed on your vial and packing slip; and confirm any "ISO/IEC 17025 accredited" claim in the register of the accreditation body, not on the lab's own site. A report that passes all three is genuine, about your material, and from a laboratory whose competence someone independent has assessed.

What should a peptide lab report contain?

The content of an accredited test report is standardised. ISO/IEC 17025:2017 sets it out in clause 7.8.2.1, and FDA's laboratory accreditation rule for food testing (21 CFR 1.1152) adopts the same clause by reference, requiring reports that "Include the name and street address" of the laboratory, carry an identification unique to the report, and be "true, accurate, unambiguous, and objective". For a peptide certificate the same items make the paper checkable:

The laboratory's name and address, not a logo alone.
A unique report or verification number.
A sample identifier and a description of what was received, including the lot number printed on it.
The date received and the date issued.
The method for each figure: HPLC with its detector wavelength, mass spectrometry with the instrument type, any content assay with its basis.
The numerical value and acceptance limit for each test.
A named signatory, the person who authorises the report.

ICH Q7, the good-manufacturing-practice guidance for active ingredients, asks the same of a manufacturer's certificate: it "should list each test performed in accordance with compendial or customer requirements, including the acceptance limits", and certificates "should be dated and signed by authorized personnel of the quality unit(s)". A report missing several of these is not necessarily false, but it is unverifiable, which for a buyer is the same problem.

Step one: how do you verify a COA with the laboratory?

Many independent laboratories keep a public lookup page: enter the report or verification number and the page returns the report the lab holds under it. That confirms the document was issued by the lab and has not been edited since. Where no lookup exists, write to the lab with the report number. A laboratory that will not confirm whether it issued a document is one whose reports cannot be verified.

Two limits apply to any lookup:

Listing is usually at the client's option. A lab's public listing shows the reports its clients chose to publish. Draw no conclusion about a supplier, or a market, from a curated set.
The sample description is the client's. The lab records what it was told the sample is. Identity by mass spectrometry confirms the molecule; nothing on the report confirms the lot number on its own.

Our certificate library is built for this check. Each entry shows the laboratory's verification number, links to the file the laboratory itself serves under that number, and lists the SHA-256 fingerprint of the exact file we read, so a change to that file is detectable. Where the laboratory has reissued a certificate under the same number, the page shows the current issue and keeps the earlier one listed.

Step two: tie the report to the lot in your hand

A genuine report about a different lot tells you nothing about your vial. The lot number must be identical on vial, packing slip and report, the dates must run in order, and the report must be lot-specific rather than "representative" or "typical". What a lot number is for covers these checks in detail.

Where a supplier commissions an independent test, ask who drew the sample, from what and when. On this site each certificate comes from a third-party laboratory on a sample submitted by our supplier, and the certificate itself names the submitting party.

What does "ISO/IEC 17025 accredited" mean?

ISO/IEC 17025 is the international standard for the competence of testing and calibration laboratories. ISO does not accredit anyone. Accreditation is granted by an accreditation body that assesses the laboratory against the standard; in the United States the recognised bodies include A2LA, ANAB and NIST's NVLAP.

Three details decide whether the phrase means anything on a peptide report:

Accreditation is for a scope, not a building. NVLAP's handbook states that a certificate of accreditation "is always issued with a Scope of Accreditation". A laboratory accredited for environmental water testing is not thereby accredited for HPLC purity of synthetic peptides.
Accredited data must be marked. Under NVLAP's rules a report mixing accredited and non-accredited data "shall clearly identify the data that are not covered by the accreditation."
Accreditation covers competence, not the sample. It does not say the sample was representative or that the client described it truthfully. Why two competent labs can still differ on one lot is covered in why two laboratories get different numbers.

"Registered", "certified", "compliant with ISO 17025" and "operates to ISO 17025 principles" are not accreditation. They are descriptions a laboratory writes about itself.

Step three: check the accreditation body's register

Find the body. The report or the lab's certificate names it. ILAC's signatory search "provides a current list of all accreditation bodies that are signatories to the ILAC MRA", and ILAC notes that "in many cases, a link to the accreditation body's online directory of accredited facilities is also provided".
Search the directory. A2LA's public directory searches by "scope, test method, certificate no., organization name" and publishes a list of suspended and withdrawn certificates. NVLAP publishes its own directory.
Open the scope. Read it for the field (chemical testing), the technique (liquid chromatography, mass spectrometry) and the certificate's expiry and status.
Match the name. The legal name in the register should match the report. Trading names and "affiliated" labs are where claims drift.

If the register does not show the claim, ask the lab for its certificate number and search again. If that fails, read the report as an unaccredited report: not worthless, but a different document.

What should a long lipidated peptide's certificate show?

TP-RTA-3, a research peptide we stock as a lyophilized vial, is a 39-residue lipidated peptide with the formula C221H342N46O68, an average molecular weight of 4,731 and a monoisotopic mass of 4,728.47 (PubChem). Its certificate should show an identity line by mass spectrometry consistent with that mass, a reversed-phase HPLC purity with its wavelength, and a content figure in milligrams, which is a different quantity from purity.

A worked example from our library, current as of October 21, 2026: the certificate for TP-RTA-3 lot RETA20-0803 reports RP-HPLC (214 nm) purity of 99.79%, identity by LC-MS/MS as "Conforms", and content by HPLC quantitation of 20.22 mg, issued August 28, 2026, with the verification number that step one asks you to check. A TP-RTA-3 vial's lot number should match the lot on that page.

GHK-Cu and kisspeptin-10 certificates: what changes?

GHK-Cu. PubChem lists GHK-Cu as prezatide copper, CID 71587328, a copper complex of the tripeptide Gly-His-Lys with a molecular weight of 402.92. Because it is a peptide bound to a metal ion, read the identity line for which species it reports, the free tripeptide or the copper complex, and compare it with the matching calculated mass. The GHK-Cu lot GHK50-0803 certificate reports RP-HPLC (214 nm) purity of 99.77%, LC-MS/MS identity "Conforms" and 51.02 mg content. GHK-Cu is a copper tripeptide we stock as a lyophilized vial.

Kisspeptin-10. A ten-residue peptide, YNWNSFGLRF, formula C63H83N17O14, molecular weight 1,302.4 (PubChem CID 25240297). At this size a MALDI or electrospray spectrum should land close to the calculated mass with little ambiguity. The kisspeptin-10 lot KISS10-0528 certificate reports RP-HPLC (214 nm) purity of 99.9%, MALDI-MS identity "Conforms" and 10.05 mg content, issued June 17, 2026.

The same three checks apply to each: confirm the number with the lab, match the lot, confirm the accreditation claim.

What verification cannot tell you

Every step above verifies documents. None verifies material. A verified, accredited, lot-specific report can describe a sample tested at release rather than the vial that shipped, and is silent about what happened in transit afterwards. The remedies are a second sample drawn after arrival, a lot number that stays published so it can be checked later, and a supplier who will say in writing who drew which sample when.

The checklist

Check	Where	What it proves
Report number returns the same document	Laboratory lookup or written confirmation	The lab issued it and it is unedited
Lot number identical on vial, slip, report	Your bench	The report is about your material
Method, date, signatory, limits present	The report	The report is complete enough to check
Identity mass matches the molecule	The report and PubChem	The right peptide was found
"Accredited" appears in the body's register	A2LA, ANAB, NVLAP or an ILAC signatory's directory	The claim is real
Scope covers chromatography and mass spectrometry	The scope document	The claim applies to this report
Who drew the sample, from what, when	The supplier, in writing	The sample is the lot

Frequently asked questions

How do you verify a certificate of analysis?

Enter the report or verification number on the issuing laboratory's lookup page, or write to the lab, and confirm the document and figures match. Then match the lot number to your vial and check any accreditation claim in the accreditation body's register.

Can a peptide COA be checked without contacting the supplier?

Yes. The report number is checked with the laboratory and the accreditation with the accreditation body, neither of which the supplier controls. Only the question of who drew the sample needs the supplier.

Where are Touchstone's certificates?

In the certificate library. Each entry shows the lot, the figures, the laboratory's verification number and a link to the laboratory's own copy.

What does ISO 17025 accredited mean for a testing laboratory?

An accreditation body has assessed the laboratory against ISO/IEC 17025 and issued a certificate with a scope of methods. ISO itself accredits no one, and the claim is checked in the accreditation body's register.

Does a lab report lookup prove the report is about your vial?

No. It proves the laboratory reported those figures under that number for the sample it received. The lot number on the report still has to match the vial and packing slip.

Sources

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For laboratory research use only. Not a drug, not a supplement, and nothing here is a claim about what any of this material does in a person or an animal.