How to Read a Peptide Certificate of Analysis (Janoshik Explained)

A peptide certificate of analysis (COA) is a report from a testing laboratory that states what a sample is, how pure it is and, where tested, whether it is free of endotoxins. To read one, check the header for the compound and batch number, confirm the HPLC purity figure is supported by a chromatogram, confirm the mass-spec result matches the expected molecular weight, then verify the report number directly with the issuing lab. If any of those four steps fails, treat the certificate as unproven.

What a peptide certificate of analysis actually is

A COA is a snapshot of one sample from one batch, analysed on one date by a named laboratory. It is not a licence, a safety approval or a guarantee about every unit ever sold under that product name. Its value lies in three things: the lab that issued it, the methods used, and whether the batch number on the report matches the batch number on the product in your hand.

There are two broad types. A manufacturer COA is produced by the factory that synthesised the peptide, usually on the raw powder before it is shipped. A third-party or independent COA is produced by a lab with no commercial interest in the result, on a sample submitted by the supplier or a customer. Independent testing is the more useful of the two because it checks what actually arrived, not what left the factory.

Who is Janoshik Analytical?

Janoshik Analytical is an independent analytical laboratory based in the Czech Republic that has become the most widely used third-party tester in the research peptide market. It accepts samples from suppliers and from individual buyers, runs HPLC purity, mass spectrometry identity and, on request, endotoxin and quantitative content testing, and publishes a report with a unique ID.

The reason Janoshik reports carry weight is that they can be verified. Every report ID can be entered on the lab website and the original record loaded, which makes a forged or edited PDF easy to catch. Calibre uses Janoshik for every batch and publishes the reports on our COA page so buyers can run that check themselves.

Section by section: the header

The top of a Janoshik COA carries the administrative detail, and it is worth reading slowly because this is where mismatches most often appear. You should find the following fields.

• Report or sample ID: the unique number used for verification.
• Client: the name of the company or individual who submitted the sample.
• Sample description: the compound name as declared by the submitter, and often the claimed content (for example 10 mg).
• Batch or lot number: must match the label on your product.
• Date received and date of analysis.
• Tests performed: usually HPLC purity and mass spectrometry, sometimes endotoxin (LAL) and quantitative assay.

If the batch number on the report does not match the batch number on the pen or vial, the certificate does not apply to your product, no matter how good the numbers look. If there is no batch number at all, the report is effectively a marketing document.

HPLC purity: the number everyone looks at

High-performance liquid chromatography (HPLC) separates the components of a dissolved sample as they pass through a column, with a UV detector recording each component as a peak. Purity is calculated as the area of the main peak divided by the total area of all peaks, expressed as a percentage. A result of 99.2% means that 99.2% of the UV-detectable material in the sample eluted as the main compound and 0.8% eluted as something else.

A good COA shows the chromatogram and the integration table, not just a headline figure. If a report states 99.5% but has no trace attached, you cannot tell whether the impurity peaks were resolved properly or whether a related impurity is hiding under the main peak.

Mass spectrometry: is it the right molecule?

HPLC tells you how much of the sample is one compound. It does not tell you which compound. That is the job of mass spectrometry (MS), which measures the mass-to-charge ratio of the ionised sample and reports a molecular weight. The COA will state the theoretical molecular weight for the declared peptide and the observed value from the instrument.

The two should agree closely, usually within a fraction of a Dalton for a well-calibrated instrument, allowing for the charge states that larger peptides carry. A sample that is 99% pure by HPLC but whose mass does not match the declared peptide is 99% pure something else. Janoshik reports typically state whether identity was confirmed alongside the observed mass.

Endotoxin and quantitative lines

Not every COA includes an endotoxin result, because it is a separate test with a separate cost. Where it is present, the value is reported in endotoxin units (EU) per milligram or per millilitre, measured by the Limulus amebocyte lysate (LAL) method. Endotoxins are fragments of bacterial cell wall that HPLC and MS cannot see, so a low endotoxin result is additional evidence of clean manufacturing rather than a restatement of purity.

Some reports also include a quantitative assay, which measures how many milligrams of peptide are actually in the vial or cartridge compared with the label claim. This is different from purity. A vial labelled 10 mg might contain 9.6 mg of material that is 99% pure, or 7 mg of material that is 99% pure; both would show the same purity but very different content. For pre-filled pens, a content result against the labelled concentration is particularly useful.

Red flags on a peptide COA

1. No report ID, or an ID that returns nothing when entered on the lab website.
2. A batch number that does not match the product label, or no batch number at all.
3. A purity figure with no chromatogram or integration table.
4. A mass-spec section that is missing, or an observed mass that does not match the declared peptide.
5. A report dated years ago being used for a current batch.
6. Purity claims of exactly 100%, which is not a realistic HPLC result for a synthetic peptide.
7. A PDF whose fonts, spacing or alignment differ between fields, suggesting editing.

None of these on its own proves a certificate is fake, but each one should prompt you to contact the supplier and ask for the original report link. A UK supplier with nothing to hide will send it without hesitation.

How to verify a Janoshik report

Verification takes under a minute. Locate the report ID on the COA, open the Janoshik verification page (verify.janoshik.com) in a browser rather than following a link embedded in the PDF, and enter the ID. The record that loads is held by the lab, not the supplier, so compare the compound name, batch, date, purity and observed mass against the document you were given. Every field should match exactly.

If the lab record differs from the PDF in any way, the PDF has been altered. If the record does not exist, the report was not issued by Janoshik. Calibre publishes the report for each batch on our COA page precisely so that this check is straightforward; if you would like the direct verification link for a specific batch, contact us by WhatsApp, Telegram or email at sales@calibre-pens.co.uk.

Putting it together

Reading a peptide certificate of analysis comes down to four checks: the header matches your product, the HPLC purity is supported by a real chromatogram, the mass spectrometry confirms the identity, and the report ID verifies with the lab. Endotoxin and quantitative lines are valuable extras. A supplier that makes all of this easy to find is telling you something about how they operate, and that is usually the most reliable signal of all.