How to Read a Janoshik COA: HPLC, Mass Spec, and the Unique Key Explained

How to read a Janoshik peptide COA test report Durham Peptides Canada

A Janoshik Certificate of Analysis is the document every serious Canadian peptide buyer should know how to read. It's the primary piece of evidence that a peptide is what the supplier claims it is — manufactured to research-grade purity, correctly identified by molecular weight, and traceable to an independent laboratory with a verifiable test record.

But COAs contain specialized analytical data, and for researchers who haven't worked with analytical chemistry documents before, the numbers and chromatograms can be intimidating. This guide walks through what each section of a Janoshik COA actually shows, what the values mean in practice, and how to distinguish a legitimate high-purity COA from a low-quality or fabricated one.

For the verification process itself — using the unique key to confirm the COA exists in Janoshik's database — see our companion article How to Verify a Janoshik Test Report Unique Key: A Step-by-Step Guide for Canadian Buyers. This article focuses on reading and interpreting the COA data itself.

What a Janoshik COA Is

Janoshik Analytical is an independent peptide testing laboratory that provides purity, identity, and quantitative analysis for peptide samples submitted by manufacturers and suppliers. A Janoshik COA is the test report documenting those results. For the broader overview of what Janoshik is and why it's become the industry standard, see How to Verify a Janoshik Certificate of Analysis (COA).

Every legitimate Janoshik COA has the same structural elements:

• Sample identification (what peptide was tested)

• Client information (who submitted the sample)

• Test date and batch reference

• Analytical results (HPLC purity, mass spectrometry identity, water/moisture content)

• Chromatograms and mass spec traces (the actual graphical data)

• Conclusion statement

• Unique verification key that can be verified on Janoshik's official site

Learning to read each of these sections tells you more about the quality of the peptide than any marketing copy could.

Section 1: Sample Identification

The top of the COA identifies what was tested. This typically includes:

• The peptide name (e.g., BPC-157, Retatrutide, GHK-Cu)

• The declared molecular formula

• The declared theoretical molecular weight

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What to check: The peptide name should match the product you're buying, and the molecular weight should match the known value for that peptide. A few reference values:

• BPC-157: C62H98N16O22 / theoretical MW 1419.54 g/mol

• TB-500: C17H27N3O4 · (C3H5NO)28 / fragment MW varies by manufacturer specification

• GHK-Cu: C14H24N6O4Cu / MW 340.86 g/mol (including copper)

• Semaglutide: C187H291N45O59 / MW 4113.58 g/mol

• Tirzepatide: C225H348N48O68 / MW 4813.45 g/mol

• MOTS-c: C93H146N22O21S / MW 1963.33 g/mol

If the molecular weight on the COA doesn't match the expected value for that peptide within normal rounding tolerances, the sample may not be what it claims to be. This is the first and easiest check.

Section 2: HPLC Purity Analysis

High-Performance Liquid Chromatography (HPLC) is the analytical technique used to measure peptide purity. For the full science behind HPLC, see What Is HPLC? The Science Behind Peptide Purity Testing.

On the COA, the HPLC section includes:

A numerical purity percentage. This should be ≥99% for research-grade peptides. Durham Peptides' catalog is manufactured to this standard across all products — BPC-157, TB-500, GHK-Cu, retatrutide, and the rest.

An HPLC chromatogram. This is a graph showing the detector response over time. A high-purity peptide shows a single dominant peak representing the target peptide, with minimal smaller peaks nearby. A chromatogram with multiple large peaks, a broad and poorly resolved main peak, or a main peak with obvious shoulders suggests the sample has significant impurities even if the numerical purity value looks reasonable.

Method parameters. The COA typically lists the HPLC column used, the mobile phase gradient, the flow rate, the detection wavelength, and the run duration. These are technical parameters that verify the test was run under defensible analytical conditions.

What "99% purity" means in practice: the peptide sample is 99% the intended target molecule, with 1% or less combined related impurities (truncated sequences, oxidized variants, deletion products, etc.). Going from 97% to 99% purity is a significant manufacturing achievement — it requires better synthesis, better purification, and more rigorous quality control.

Section 3: Mass Spectrometry Identity Confirmation

Mass spectrometry (MS) confirms that the molecule in the vial is actually the peptide it's claimed to be. HPLC tells you how pure the sample is; mass spec tells you whether the pure fraction is the correct molecule.

On the COA, the MS section includes:

The observed molecular weight. This should match the theoretical molecular weight from the sample identification section within a very tight tolerance (typically less than 1 Dalton difference for most research peptides).

A mass spectrum trace. This is a graph showing ion intensity by mass-to-charge ratio (m/z). The dominant peak should correspond to the target peptide's molecular weight (often shown at [M+H]+ or [M+2H]2+ depending on the ionization).

Method parameters. The ionization method (ESI is common for peptides), the instrument type, and the mass range scanned.

What to look for: A clean mass spectrum with a dominant peak at the expected m/z indicates correct identity. Multiple major peaks at unrelated m/z values, or a dominant peak at an unexpected mass, suggests the sample is either not the claimed peptide or contains significant contamination.

Mass spec identity confirmation is particularly important for newer or less-common peptides where adulteration or substitution might not be caught by HPLC alone. HPLC purity and MS identity together form the pair of tests that define a legitimate COA.

Section 4: Water/Moisture Content

Research peptides are supplied as lyophilized (freeze-dried) powder. Residual moisture content affects shelf stability and the accuracy of any per-milligram calculations. The COA usually reports water content as a percentage, typically measured by Karl Fischer titration or thermogravimetric analysis.

Typical water content for a well-lyophilized research peptide is 2-8%. Higher values (above ~10%) suggest incomplete lyophilization and can shorten shelf life. Very low values (below ~1%) are possible but uncommon.

This section is less central to quality evaluation than purity and identity, but it's one of several data points that together characterize a well-manufactured peptide.

Section 5: Peptide Content / Net Peptide Mass

Some Janoshik COAs report "net peptide content" — the actual peptide mass as a percentage of the total sample mass, after accounting for water, counter-ions (typically trifluoroacetate or acetate from the purification process), and other non-peptide material.

This matters because when you buy a "10mg BPC-157 vial," the total vial contents might weigh slightly more than 10mg, with a portion of that weight being non-peptide material. Net peptide content of 80-95% is typical for TFA-counterion peptides, and 85-95% is typical for acetate-counterion peptides.

Suppliers who advertise their peptides with emphasis on "net peptide mass" vs "total peptide weight" are being more precise about what you're actually receiving. Most research protocols account for this at the reconstitution and calculation stage. For reconstitution math, see How to Reconstitute Peptides: A Step-by-Step Guide for Researchers — or use our peptide calculator to run the volume math directly with your vial size and research protocol inputs.

Section 6: Conclusion Statement

Near the end of the COA, Janoshik typically includes a conclusion statement summarizing whether the sample passes the specifications claimed by the submitting party. This is often a one-line confirmation such as "Sample conforms to the specification provided by the client" or similar language.

A passing conclusion is necessary but not sufficient evidence of quality. The underlying data (HPLC, MS, moisture, net peptide content) is what actually characterizes the sample — the conclusion statement is just the summary.

Section 7: The Unique Verification Key

At the bottom of every legitimate Janoshik COA is a unique verification key. This is typically an alphanumeric string of around 10-20 characters. The key is the mechanism that proves the COA actually exists in Janoshik's database — it's not just a document the supplier created themselves.

The verification process:

1. Go to janoshik.com/verify

2. Enter the unique key from your COA

3. Janoshik's database returns the test record, including the sample identification, test date, and results

If the key doesn't verify — if Janoshik's site returns "no record found" or any error — the COA is not legitimate, regardless of how professional the PDF looks. Fabricated COAs are rare but not unheard of in the peptide industry, and the verification key exists specifically to defend against this.

For the full step-by-step verification walkthrough, see How to Verify a Janoshik Test Report Unique Key: A Step-by-Step Guide for Canadian Buyers.

Red Flags When Reading a COA

Certain patterns indicate a problematic COA worth investigating:

The unique key fails to verify. This is the single most serious red flag. A non-verifying key means the COA is not authentic, period.

The molecular weight doesn't match the expected value for the peptide. Off by more than a few Daltons indicates the sample may not be the claimed peptide.

The HPLC chromatogram shows multiple large peaks or a broad/unresolved main peak. This suggests significant impurities even if the numerical purity value looks fine.

The mass spectrum doesn't show a clean dominant peak at the expected mass. Identity uncertainty.

The COA is not dated or is significantly older than the batch you're buying. Reputable suppliers test each batch, and the COA should be relatively recent relative to your purchase date.

The client name on the COA doesn't match the supplier you're buying from. Some suppliers legitimately share manufacturing sources, but the COA should tie back to the entity that actually tested the peptide in your possession. A mismatch here is worth asking about.

Section headings or data appear altered. Fabricated or modified COAs sometimes show inconsistencies in formatting, font, or numerical alignment that suggest editing of an original document.

Durham Peptides and Janoshik Testing

Durham Peptides submits peptide samples to Janoshik Analytical for independent testing. Every product in our catalog ships with a Janoshik COA and a unique verification key. Our full test report archive is available on the Lab Results page — buyers can review our testing data before placing an order.

We chose Janoshik specifically because the laboratory has become the widely recognized standard in the research peptide industry. Using Janoshik means our testing is directly comparable to testing from other reputable suppliers, and buyers can run the same verification process regardless of which Canadian vendor they're evaluating.

Frequently Asked Questions

What is a Janoshik COA? A Certificate of Analysis from Janoshik Analytical, an independent peptide testing laboratory. It reports HPLC purity, mass spectrometry identity, and other quality parameters for a peptide sample.

What does HPLC 99% purity mean on a COA? It means that 99% of the peptide sample is the intended target molecule, with 1% or less combined related impurities as measured by High-Performance Liquid Chromatography.

What's the difference between HPLC and mass spectrometry on a COA? HPLC measures how pure the sample is. Mass spectrometry confirms the identity of the molecule. Both are needed for a complete quality assessment.

What is the unique key on a Janoshik COA? An alphanumeric identifier at the bottom of the COA that can be verified at janoshik.com/verify to confirm the COA exists in Janoshik's database.

How do I verify a Janoshik COA? Enter the unique key at the Janoshik verification page. If the key returns a matching test record, the COA is legitimate. See our step-by-step verification guide.

What if the unique key on my COA doesn't verify? Contact the supplier immediately. A non-verifying key means the COA is not legitimate, and you should not trust any quality claims attached to it.

What molecular weight should BPC-157 show on a COA? 1419.54 g/mol (theoretical). Observed MS values should match within a small tolerance.

What's the difference between HPLC purity and net peptide content? HPLC purity measures the fraction of the peptide sample that is the target molecule. Net peptide content measures the fraction of the total vial mass that is peptide vs non-peptide material (water, counter-ions).

Can a COA be fake? Yes. Fabricated COAs exist in the research peptide industry. The unique verification key is the specific defense against this — a non-verifying key indicates a non-legitimate COA regardless of how professional the PDF appears.

Do all peptide suppliers use Janoshik? No. Janoshik is the widely recognized standard in the industry, but other labs also perform peptide testing. The key criteria are that the testing is independent (not performed by the supplier themselves), that the COA includes HPLC and MS data, and that there's a verifiable record of the test.

Are Durham Peptides' COAs available to view before ordering? Yes. Our Lab Results page includes testing data for our catalog. Each order also ships with the specific batch COA for the peptide purchased.

Does each batch get a new COA? Yes. Reputable suppliers test each new batch, so the COA corresponds to the specific batch of peptide in your vial.

Final Thoughts

Reading a Janoshik COA is a skill worth developing for any Canadian researcher working with peptides. The combination of HPLC purity, mass spectrometry identity, moisture content, and a verifiable unique key provides the complete picture of a peptide's quality — and a researcher who knows how to read each section can evaluate any supplier's claims on the data rather than on marketing.

For Durham Peptides' complete approach to testing and quality control, see our Lab Results page. For the broader framework on evaluating Canadian peptide suppliers, see 5 Things to Look for in a Canadian Peptide Supplier and How to Buy Peptides in Canada: A Complete Guide for 2026.

Browse our full catalog of Janoshik-verified Canadian research peptides at durhampeptides.ca.

Selected Research References

1. Snyder LR, Kirkland JJ, Dolan JW. Introduction to Modern Liquid Chromatography. 3rd ed. Hoboken, NJ: Wiley; 2010. Foundational text on HPLC methodology.

2. Marty MT, Baldwin AJ, Marklund EG, et al. Bayesian Deconvolution of Mass and Ion Mobility Spectra: From Binary Interactions to Polydisperse Ensembles. Analytical Chemistry. 2015;87(8):4370-4376. https://pubmed.ncbi.nlm.nih.gov/25799115/

3. Lacroix M, Kinsey BM, Bianco AE, Jankowski M, Gérard E, Rabhi-Essafi I. Quality Assessment and Quality Control of Short- and Long-Chain Peptides by UV and Evaporative Light Scattering Detection. Journal of Pharmaceutical and Biomedical Analysis. 2011;56(5):1041-1047. https://pubmed.ncbi.nlm.nih.gov/21908121/

4. Loo JA. Studying Noncovalent Protein Complexes by Electrospray Ionization Mass Spectrometry. Mass Spectrometry Reviews. 1997;16(1):1-23. Foundational review of MS for peptide and protein analysis.

5. United States Pharmacopeia. USP <1224> Transfer of Analytical Procedures. General Chapter on validation and transfer of analytical methods including HPLC.

All products sold by Durham Peptides are for research and laboratory use only. They are not intended for human or animal consumption, diagnosis, treatment, cure, or prevention of any disease.