Batch number
The batch or lot number links the report to the specific material that was submitted for analysis. The identifier on the report should match the identifier shown in the corresponding Pepy batch documentation.
Laboratory documentation guide
How to Read a Peptide Certificate of Analysis
A Certificate of Analysis records the results reported for an identified sample or batch. This guide explains how to read common fields, understand what each result does and does not show, and match a report to Pepy’s laboratory documentation.
What is a Certificate of Analysis?
A Certificate of Analysis, often shortened to COA, is a laboratory document that records the sample details, tests performed and results reported for the material identified on the document. Its scope is limited to the stated sample, methods and report information.
Key fields to check on a peptide COA
Test date
The test date records when the stated analysis was performed or reported. Read it together with the batch number; a recent date does not make the result applicable to a different batch.
Reported purity
Purity is the value reported by the laboratory under the analytical method described in the document. It concerns the measured signal within that method and should not be treated as a measurement of every property of the sample.
Compound identity
Identity testing addresses whether the measured characteristics are consistent with the named compound. Check the report for an explicit identity result and the method used rather than inferring identity from a purity value.
Net content
Net-content testing addresses the reported quantity of material in the tested sample. A sample can have a reported purity result without a separate net-content result, so the two fields should be read independently.
Endotoxin testing
Endotoxin is a separate test category. Treat it as tested only when the report explicitly records the test, method or units where supplied, and result; an omitted field is not a result.
Sterility testing
Sterility is also a separate test category. A purity or identity result does not establish sterility, and no sterility conclusion should be drawn unless the report explicitly includes that test and its reported result.
Why a result belongs to one batch
A COA records findings for the sample identified in that document. Its results do not automatically describe another production lot, a later batch or every unit sold under the same compound name.
The compound name, strength, batch number and report date should therefore be considered together. If the batch identifier does not match, the report should not be used as documentation for that material.
Purity is only one reported measurement
A reported purity value does not by itself prove compound identity, net content, endotoxin status or sterility. Those questions require their own reported tests and must not be assumed from one analytical result.
A COA also does not establish that material is suitable for human or veterinary use. Pepy documentation is provided strictly for laboratory and research reference.
How to cross-check a report
- 01
Confirm that the compound name and listed strength match the material being reviewed.
- 02
Match the report’s batch or lot number to the batch identifier shown with the product documentation.
- 03
Check the test date, issuing laboratory and report identifier where those details are supplied.
- 04
Read each result only under its stated test category; do not substitute purity for identity, content, endotoxin or sterility testing.
- 05
Open the original document and note any methods, units, qualifiers or limitations recorded by the laboratory.
Fake-certificate checks and red flags
Compare the chromatogram with the stated purity. A claim of 99.5% should be supported by one dominant peak and only small neighbouring peaks. An unnaturally flat baseline, no noise, or a result of exactly 100.00% warrants questions, but is not by itself proof of fraud. Check the column, mobile phase, gradient, flow rate and detection wavelength; peptide backbones are commonly detected around 210–220 nm. Use the chromatogram walkthrough for interpreting the trace.
For mass spectrometry, request the spectrum and observed mass or m/z values rather than relying only on “MS: conforms”. Electrospray can produce multiple charge states. Check that the observed mass agrees with the appropriate theoretical mass and instrument tolerance, accounting for charge state and average versus monoisotopic mass. Cross-check formula and sequence in the research peptide reference table.
Signs of reuse or editing
- Several products or sizes sharing an identical certificate needs explanation; confirm the report's stated scope.
- Check the order of synthesis or receipt, analysis and report issue. A report issued before analysis, or analysis long before sale, needs explaining.
- Reverse image search can reveal the same report elsewhere with a different logo, compound or batch number.
- Watch for changes in fonts, sizes or alignment around the purity and batch fields, blurred patches, reused chromatograms and stretched or outdated logos.
- PDF properties may show an editing application or a creation date much later than the report date. Labs also generate PDFs through software, so this is a prompt to investigate, not proof of alteration.
Verify with the issuing laboratory
- Find the laboratory independently through a search engine rather than trusting contact details printed on the certificate.
- Check accreditation and its scope. In Australia, use NATA; overseas, consult the ILAC MRA signatories. Accreditation applies to defined methods, not every possible test.
- If a report number or QR code opens an online verification portal, confirm that it uses the lab's real domain.
- Ask the lab whether the report number and batch number match its records.
A summary report without a chromatogram is not automatically fake. An unaccredited laboratory can produce useful data, but accreditation provides an independent competence assessment within its stated scope. Resolve unexplained mismatches before relying on a certificate for a vial.
Verification sources
For laboratory research use only. Not for human or veterinary use.
Printable checklist
Print this section and tick each item against the certificate and the vial in front of you. A warning sign is a reason to verify, not proof of fraud.
For laboratory research use only. Not for human or veterinary use.
Educational laboratory reference only. This page does not provide dosing, administration, medical, therapeutic or human-use guidance, and it does not replace the original laboratory report.