How to Read a Peptide COA + Verify a Janoshik Report

A peptide Certificate of Analysis (COA) is a batch test report documenting a specific lot’s identity (is it the molecule on the label?) and purity (how much of the detected material is that molecule?). 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 four things in order: the compound name and lot number, the HPLC purity percentage, the mass-spectrometry identity confirmation, and the issuing lab. You then confirm it is genuine by looking the report up directly on the testing lab’s own website using the report ID printed on the page. 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 two analytical questions about one specific batch of material, and nothing more:

• 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 target 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 a lot number that does not match the vial you hold, is not evidence about your material.

How to read each field of a peptide COA

Real reports vary in layout, but a credible third-party peptide COA contains the same 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 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 proves nothing about 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 target 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 target peak accounts for that share of the detected material. 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 batches carry extra independent tests beyond identity and purity, such as an endotoxin (LAL) assay or a heavy-metals panel by ICP-MS. These are separate analyses with their own pass/observation criteria and are reported as distinct sections. Their presence or absence does not change how you read the identity and purity fields — it simply tells you how much additional characterisation the batch received.

6. Issuing laboratory and report ID

A third-party COA names the independent lab that performed the testing and carries a report identifier or verification code. This is what makes the document checkable. The lab name plus the report ID are the two pieces of information you use to confirm the report is real, 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 removes that risk: you are reading the lab’s copy, generated by the lab, not a file forwarded to you.

1. Find the report ID or verification code. It is printed on the COA itself and is also surfaced for every tested batch in our own batch verification tool.
2. Open the lab’s verification portal in a browser. Go to verify.janoshik.com in a normal web browser (Chrome, Safari, or Firefox).
3. Enter the report code and compare. The lab’s own record loads with the compound, the lot, the HPLC purity, and the MS data. Compare every field against the COA you were given. They should match exactly. Any discrepancy — a different purity figure, a different lot, a missing MS section — means the document you hold is not a faithful copy of the lab’s record.

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 confirm for yourself that the report we show is the report the lab issued. 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 carries a report ID you can independently verify. If there is no lab, no report number, or no way to check it on the lab’s own system, treat it as unverifiable.
• The report ID does not resolve on the lab’s portal. If the code is not found, or loads a record that disagrees with the PDF, the document has been altered or fabricated. This is the single strongest test — a forged PDF cannot fake the lab’s own database entry.
• Missing lot number, or a lot that does not match your batch. A COA with no traceable lot is a marketing image, not evidence about your material.
• Purity claimed with no chromatogram. A bare “99% pure” statement with no HPLC trace gives you nothing to inspect. A genuine report shows the chromatogram so you can see the peak resolution behind the number.
• HPLC percentage but no mass-spec identity. Purity without identity confirmation is half a report: it can show the main component is clean without showing it is the right molecule.
• 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 verify the report ID directly on the lab’s site.
• 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 identity confirmation, the chromatogram quality, and whether the report verifies on the issuing lab’s portal.

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 confirm a report is genuine.
• Use the batch verification tool to look up the actual Janoshik report for a specific product and lot — it links straight to the lab’s record.
• 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 third-party laboratory report documenting one specific batch’s identity and purity. It confirms whether the material is the peptide named on the label (typically by mass spectrometry) and what percentage of the material is that peptide (typically by HPLC), and it names the issuing lab plus a report ID so the document can be independently verified.

How do I verify a Janoshik report?

Take the report ID or verification code printed on the COA, open verify.janoshik.com in a normal web browser, and enter the code. The lab’s own record loads with the compound, lot, HPLC purity, and mass-spec data; 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. For our products, our verification tool surfaces each batch’s code and links directly to the lab’s record.

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 mass-spec identity confirmation, the quality of the chromatogram, and whether the report verifies on the issuing lab’s portal — 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 tells you how much of the sample is the dominant component; 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. A complete COA reports both.

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 portal: verify.janoshik.com
• CertaPeptides batch verification tool (per-lot Janoshik report lookup): 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.