How to Read a Peptide COA + Verify a Janoshik Report

A peptide Certificate of Analysis (COA) is a test report on a sample from one specific lot. Depending on the tests the lab ran, it reports an identity result (typically whether the measured mass matches the molecule on the label), purity (the main peak’s share of the total detected peak area) or content. The strongest form is a COA you can independently verify against the issuing third-party lab, rather than an in-house document you have to take on trust. You read it by checking, in order, the compound name and any lot identifier the report gives, the results of the tests it covers and the issuing lab. You then look the report up on the public page of the testing lab or its certificate provider, using the identifiers printed on the report (for Janoshik, the task number and the unique key), and compare the two. Everything below walks through each field, then shows how to verify a real Janoshik report so you are reading the lab’s copy, not a PDF that could have been edited.

For research purposes only. The information here describes how to interpret analytical identity and purity data on a laboratory document. It is not guidance on safety for use, human consumption, or any application beyond laboratory research. CertaPeptides is a reseller of research compounds, not a manufacturer or testing laboratory.

What a peptide Certificate of Analysis actually tells you

A COA answers only the analytical questions its tests cover, for a sample from one specific batch. The two most common are:

• Identity — is the substance in the vial the peptide named on the label? This is established primarily by mass spectrometry (MS), which measures the molecule’s mass so it can be matched against the expected molecular weight of the named peptide.
• Purity — of the components the instrument detects, what share is the target peptide rather than synthesis by-products or truncated sequences? This is established primarily by high-performance liquid chromatography (HPLC), which separates a sample’s components and reports the main peak as a percentage of the total detected peak area. Note that HPLC area-percent is not a total mass fraction: it does not account for salts, water, or counterions, and it does not see non-UV-absorbing impurities. Residual solvents and reagents need separate methods.

A COA is batch-specific. It applies to the lot it was generated from, not to the product line in general. That is why the lot/batch number on the report is as important as the purity figure: a COA with no lot number, or with a lot number that does not match the vial you hold, does not establish results for that vial.

How to read each field of a peptide COA

Real reports vary in layout and in the tests they cover, but a credible third-party peptide COA usually contains these core fields. Here is what each one means and what a careful reader checks.

1. Compound name and stated quantity

The top of the report usually names the peptide tested and the nominal amount (for example, a 10 mg lyophilised sample). Check that this matches the product you are verifying. Note that a peptide can be supplied as different salt forms; the named compound on a COA reflects what was submitted to the lab. As a reseller, we list the material as our supplier provides it.

2. Lot / batch number

The single most important traceability field. The lot number ties the report to a physical batch. To trust a COA, the lot on the report must correspond to the batch you received. A report whose lot number is blank, generic, or unrelated to your shipment does not establish results for the vial in front of you.

3. HPLC purity (the headline number)

HPLC separates everything in the sample over time and produces a chromatogram — a trace with peaks. The target peptide elutes as one peak; impurities appear as additional, usually smaller, peaks. The reported purity is the area of the main peak expressed as a percentage of the total peak area. When a COA says, for instance, that a peptide is above 98% pure by HPLC, it means the main peak accounts for that share of the total detected peak area. Read the chromatogram itself, not just the headline number: a clean trace shows one dominant, well-resolved peak; a noisy trace with several large secondary peaks deserves scrutiny even if the stated percentage looks high.

4. Mass spectrometry (identity confirmation)

HPLC tells you how pure the main component is; it does not, on its own, prove that component is the right molecule. That is what mass spectrometry is for. The MS section reports the measured mass of the dominant species. A genuine identity confirmation shows the observed mass matching the theoretical molecular weight of the named peptide (within the instrument’s expected tolerance). If a report shows a high HPLC purity but the MS mass does not correspond to the named compound, the material may be pure — but pure something else.

5. Additional panels (when present)

Some reports include other independent tests, such as an endotoxin (LAL) assay or a heavy-metals panel, beside or instead of identity and purity results. These are separate analyses, reported in their own section or in a report of their own. Their presence or absence does not change how you read any identity and purity results the report gives — it tells you which tests the report covers.

6. Issuing laboratory and report ID

A third-party COA names the independent lab that performed the testing and usually carries a report identifier or verification code. This is what makes the document checkable. The lab name and the report’s identifiers are what you use to look the report up and compare it with the issuer’s own record, which is the next step.

How to verify a Janoshik report (step by step)

We publish independent third-party Janoshik Analytical reports for tested batches — Janoshik is an independent analytical laboratory in the Czech Republic that runs a verification portal for its reports. Not every lot carries a published report, so check the COA / Verify badge on the specific product you are looking at. Verification matters because a PDF can be altered — numbers changed, a lab’s name pasted onto someone else’s data. Looking the report up on the lab’s own system lets you read the lab’s copy, generated by the lab, instead of a file forwarded to you, and compare the two.

1. Find the task number and unique key. Both are printed on the Janoshik reports we publish. Our own batch verification tool also finds a published report by its report code, and by the lot code on your vial where the report records that lot, and links to its record.
2. Open the lab’s verification portal in a browser. Go to janoshik.com/verification in a normal web browser (Chrome, Safari, or Firefox).
3. Enter both and compare. The lab’s own record loads with the identifying details and measured results that report contains. Compare every field against the COA you were given. They should match exactly. Any discrepancy — a different purity figure, a different lot, a missing section — means the document you hold does not match the lab’s current record: treat it as unverified until the issuer explains the difference.

To make this concrete, our published Ipamorelin 10 mg batch carries the Janoshik verification code IT2JSP8AGYWZ. You can look that code up in our verification tool, which links straight through to the lab’s record, and check for yourself that the report we show matches the lab’s record. That is the whole point of independent verification: you should not have to take our word for it.

How to spot a fake or edited COA

Most fraudulent or misleading COAs fail one of a small number of checks. Run through this list before trusting any peptide certificate of analysis:

• No issuing lab named, or a lab that cannot be looked up. A real third-party COA names the lab and usually carries a report ID you can check with that lab. If there is no lab, no report number, or no way to check it on a public page of the lab or its certificate provider, treat it as unverified.
• The report cannot be found on the public page of the lab or its certificate provider. Check that you entered every identifier the page asks for exactly as printed (for Janoshik, the task number and the unique key); until the report is found, treat the document as unverified. If it loads a record that disagrees with the PDF, the PDF does not match the current public record: treat it as unverified until the issuer resolves the discrepancy. The lookup compares the document with the issuer’s current record; whether the report belongs to your vial is a separate check (the lot number).
• Missing lot number, or a lot that does not match your batch. A COA with no traceable lot does not establish results for the vial in front of you.
• Purity claimed with no chromatogram. A bare “99% pure” statement with no HPLC trace gives you nothing to inspect. Where a report gives an HPLC purity figure, ask to see the chromatogram behind it, so you can check the peak resolution.
• HPLC percentage but no mass-spec identity. Purity without identity confirmation answers only one of the two questions: HPLC gives the main peak’s share of the detected peak area, and whether that peak is the right molecule needs its own assessment.
• Figures that look retyped onto an image. Mismatched fonts, a purity number in a different typeface from the rest of the page, or a value that contradicts the chromatogram are signs of editing. When in doubt, ignore the PDF and look the report up yourself on the public page of the lab or its certificate provider.
• A single COA reused across many batches. Because a COA is batch-specific, the same report attached to unrelated lots is a red flag — each batch should have its own.

What HPLC purity is considered good for research peptides?

For research-grade peptides, an HPLC purity at or above roughly 98% is a common benchmark for a well-made synthetic peptide, and many credible reports sit in the 98–99%+ range. But the percentage is only meaningful alongside the rest of the report: a high number on a noisy chromatogram, or with no mass-spec identity confirmation, or on a lot you cannot trace, is weaker evidence than a slightly lower number on a clean, fully verifiable report. Purity describes analytical composition for laboratory characterisation; it is not a statement about suitability for any use. Always weigh the purity figure together with any identity result the report provides, the quality of any chromatogram it includes, and whether the report can be looked up on a public page of the issuing lab or its certificate provider.

The COA and the verification tool: how they work together

This guide is the educational companion to our live tooling. Use them together:

• Read this page to understand what each field on a COA means and how to check a report against the lab’s own record.
• Enter the code printed on your vial label, or a lab report code, in the batch verification tool. It shows what CertaPeptides publishes for that code and, for a withdrawn lot, the withdrawal and its reason. If the code finds nothing, email us that code.
• For the background on why we test in the first place and what the results have shown, read why we send our products to Janoshik and what they found.

Frequently asked questions

What is a peptide COA?

A peptide Certificate of Analysis is a laboratory report on a tested sample from one specific batch, issued by the manufacturer, by the seller’s own lab or by an independent lab. Depending on the tests run, it reports whether the measured mass matches the peptide named on the label (typically by mass spectrometry), gives the main peak’s share of the total detected peak area (HPLC purity) or states the peptide content of the vial it tested (content), which is only an estimate for other vials of the batch. It names its issuer; an independent lab’s report usually also carries a report ID that you can check with that lab.

How do I verify a Janoshik report?

Take the task number and unique key printed on the COA, open janoshik.com/verification in a normal web browser, and enter both. The lab’s own record loads with the identifying details and measured results that report contains; compare each field against the COA you were given. The portal is built for human browsers and may block command-line/automated requests, so use a browser. Our verification tool finds a published report by its report code, and by the lot code on your vial where the report records that lot; it links to the report’s record on a public certificate page hosted by the testing lab or its certificate provider.

What purity is good for research peptides?

An HPLC purity at or above about 98% is a common benchmark for well-made synthetic research peptides, with many credible reports in the 98–99%+ range. The figure should always be read together with any mass-spec identity result the report provides, the quality of any chromatogram it includes, and whether the report can be looked up on a public page of the issuing lab or its certificate provider — a verifiable, clean report matters more than a higher number you cannot check. Purity is an analytical measure for laboratory characterisation, not a statement about safety or suitability for use.

Does a high HPLC percentage alone prove the peptide is correct?

No. HPLC purity gives the dominant peak’s share of the total detected peak area; it does not prove that component is the intended molecule. Mass spectrometry provides that identity confirmation by matching the measured mass to the named peptide’s molecular weight. Each test answers its own question, so check which of them a report covers.

Sources

• Janoshik Analytical — independent third-party analytical laboratory (Czech Republic) providing HPLC and mass-spectrometry testing and a public report-verification portal: janoshik.com · verification page: janoshik.com/verification
• CertaPeptides batch verification tool (Janoshik reports for the tested lots we publish): certapeptides.com/verify

Last reviewed: June 2026.

For research purposes only. Not for human consumption. For laboratory and research use only. Consult applicable regulations in your jurisdiction. CertaPeptides (CERTALAB S.R.L.) is a reseller of research compounds and is not the testing laboratory; independent analysis referenced here is performed by Janoshik Analytical.