Janoshik Testing Explained: The Default Peptide Lab

You click a vendor product page, scroll to the COA, and see the word "Janoshik" at the top of the PDF. You have seen that name on half the other vendors you have compared this month. Is that a good thing, a red flag, or just the default? And what does a clean Janoshik report actually prove about the vial you are about to inject into yourself?

This post is about Janoshik the company: the Prague lab that became the peptide community's default reference, the trust gaps that come with that, and how to read a Janoshik COA as a signal rather than gospel. If you are new to COAs in general, start with our beginner walkthrough at /blog/how-to-read-a-peptide-coa first. Everything below assumes you already know what an HPLC chromatogram is and why the retention time matters.

We aggregate Janoshik, Finnrick, and Freedom Diagnostics results in one place at peptidesrated.com/coa. That is our bias up front. We still think Janoshik deserves the default slot, and we will explain exactly why, and exactly where we would not trust them alone.

From Czech One-Man Shop to Community Default: The Janoshik Timeline

Janoshik didn't win the peptide testing market on credentials. It won on turnaround time, blind-testing ethics, and the fact that it showed up years before anyone else did.

Community reports place the founding around 2012 to 2013 by a Slovak weightlifter who wanted an independent testing option for friends in his community who kept getting burned by counterfeit anabolics. At the time, there was no service an individual consumer could send a vial to for an HPLC result. The lab started as word-of-mouth.

The formal corporate entity, Janoshik s.r.o., was registered in Prague in October 2022, roughly a decade after the informal testing service began. The lab now employs a small team and processes hundreds of tests per day, with GLP-1 agonists like semaglutide, tirzepatide, and retatrutide making up a large share of the peptide throughput.

Here is what that timeline actually means for a buyer today. When you see a 2019 COA cited by a vendor, or a 2021 result in a Reddit thread, that is the same lab, same methodology, same public lookup. The continuity is real. Most of Janoshik's competitors are less than three years old.

HPLC vs Mass Spec: What Janoshik's Instruments Actually See

HPLC tells you how much peptide is in the vial. Mass spec tells you whether it is the right peptide. If you only read the HPLC number on a COA, you are answering the wrong question half the time.

Janoshik's standard peptide workflow is HPLC with UV detection, supplemented by LC-MS/MS for identity confirmation on request or on flagged samples. That pairing matters because the two instruments answer genuinely different questions.

What HPLC does well: separates compounds by how they interact with a column, measures peak area, gives you a purity percentage. If your vial says "5mg BPC-157, 99.2% purity," the HPLC is the number generating that 99.2.

What HPLC cannot do: tell you the compound under the main peak is actually BPC-157. A well-made counterfeit with a similar retention time to the real molecule can score 99%+ on HPLC alone and be something else entirely. This is not theoretical. The larger the molecule and the more obscure the peptide, the higher the odds an HPLC-only COA is missing the real identity question.

Where mass spec closes the gap: LC-MS/MS fragments the molecule and matches the fragmentation pattern to the expected peptide sequence. For anything with a complex structure (tirzepatide, retatrutide, GHK-Cu variants, long-chain growth hormone releasing peptides), identity confirmation is non-negotiable. Our take: if you are buying tirzepatide (see our comparison at peptidesrated.com/peptide/tirzepatide) or any dual/triple-agonist and the COA is HPLC-only, treat the purity number with skepticism until you see MS identity.

Janoshik does offer MS as an add-on, not as a default. Most vendors pay for HPLC purity because it is cheaper and it is what customers scan for. A vendor who pays for full HPLC + MS on every batch is telling you something about their QA culture. A vendor whose COAs are HPLC-only is telling you something too.

The ISO 17025 Question: Accreditation Status vs Community Trust

Janoshik is not ISO 17025 accredited for peptide purity testing, and the community trusts them anyway. That is a feature of this market, not a bug, but you have to understand what you are giving up.

ISO/IEC 17025:2017 is the international standard for testing and calibration laboratory competence. Accreditation bodies use it to formally assess whether a lab's methods, documentation, staff training, and quality systems are rigorous enough to produce results suitable for regulatory submissions. An ISO 17025 accredited result is what gets accepted by the FDA, EMA, or a court.

A Janoshik COA is not that. If you wanted to submit a purity result as part of an IND filing for a pharmaceutical drug, Janoshik would not qualify. The methodology details on a public Janoshik COA are minimal. Raw chromatographic data is available only on paid request. The internal validation protocols are not published in the way FDA ICH Q2(R2) validation requires for commercial drug release testing.

So why does the peptide community use Janoshik as the default reference anyway? Three reasons, in order of how much weight we give them:

Honestly, for most research peptide buyers the answer is: treat Janoshik as credible for identity plus rough purity on the specific peptides they test often. Do not treat it as a substitute for pharmaceutical-grade release testing, because it is not, and Janoshik does not claim to be.

What Janoshik Doesn't Test: Endotoxin, Sterility, Heavy Metals, Residual Solvents

A clean Janoshik COA tells you the powder is the right molecule at roughly the right strength. It tells you nothing about whether injecting it will give you a fever.

This is the single most misread thing on a Janoshik COA. The tests on a standard peptide panel cover identity and purity. They do not cover:

This is why "99.7% pure on Janoshik" does not mean "safe to inject." A peptide can be 99.7% the correct molecule and still be manufactured in conditions that leave endotoxin at 100x the acceptable intrathecal limit. The two questions are answered by completely different assay types. HPLC separates chemical compounds. LAL (limulus amebocyte lysate) or rFC assays measure endotoxin. Sterility is a 14-day growth test.

Here is what most guides won't tell you: the vendors that brag loudest about Janoshik COAs are often silent on endotoxin testing. Ask them. A small number of research peptide vendors now publish paired reports (Janoshik for identity/purity, a separate US lab for endotoxin and sterility). That pairing is where QA culture actually lives.

Verifying a Janoshik COA Is Real: Public Lookup, Batch Conventions, Forgery Tells

Every forged COA we have seen fails the same way: the batch ID doesn't resolve on the public lookup. If you only verify one thing, verify that.

The public portal lives at public.janoshik.com. You can search by test ID (a numerical reference like #123419) or by product reference (for example, "Retatrutide 30mg"). A real Janoshik COA will have a matching entry. A forged one will have a batch number that 404s, or worse, resolves to a completely different peptide and vendor.

How forgery typically happens:

The check takes 90 seconds. Open the COA PDF. Find the test ID or reference number. Paste it into public.janoshik.com. Confirm three things match: the peptide name, the declared purity, and the date. If any of those three are off, the COA is not verifying the vial in your hand.

For more forgery and red-flag patterns beyond Janoshik specifically, we cover the full list at /blog/7-red-flags-buying-peptides.

Janoshik vs Finnrick vs Freedom Diagnostics: When Each Is the Right Reference

Finnrick is the US-based insurance policy. Freedom Diagnostics is the second opinion. Janoshik is the baseline. The three labs answer overlapping but different questions, and the smart buyer checks for agreement across at least two.

Our honest take on how to use them:

For concrete examples, Verified Peptides publishes 400+ Janoshik COAs and scores 4.9/5 in our ratings. Chameleon Peptides uses Janoshik as their stated reference lab. On the other side, Ascension Peptides uses MZ Biolabs instead, which is a valid choice but gives you less cross-community comparability because the Janoshik and Freedom Diagnostics ecosystems have much larger public databases. Our COA aggregator at peptidesrated.com/coa pulls from all three so you can cross-check a batch without bouncing between portals.

FAQ

Is a Janoshik COA enough on its own to trust a peptide vendor?

For commodity peptides (BPC-157, TB-500, GHK-Cu, semaglutide), a verified Janoshik COA is a reasonable baseline if the batch ID resolves on public.janoshik.com and the date is current. For complex peptides (tirzepatide, retatrutide, multi-agonists), we would want MS identity confirmation and ideally a second lab result. A Janoshik COA never covers endotoxin or sterility, so it is never the complete picture on injection safety.

Why is Janoshik not ISO 17025 accredited?

ISO 17025 accreditation is designed for regulated pharmaceutical and clinical lab work where results go to regulators. It is expensive, slow, and the methodology documentation requirements do not map cleanly onto gray market peptide testing. Janoshik has chosen to prioritize throughput, cost, and blind-testing integrity over the formal accreditation that the market they serve does not require. Whether you consider that a gap depends on what you are using the result for.

How do I verify a Janoshik COA is not forged?

Open the COA PDF. Locate the test ID or reference number. Go to public.janoshik.com and search that number. Confirm that the peptide name, declared purity, and date on the public lookup match the PDF. If the number does not resolve, or resolves to a different peptide or vendor, the COA is fake or reused.

Does Janoshik test for bacterial contamination or endotoxin?

No, not in their standard peptide panel. Janoshik measures chemical identity and purity via HPLC and LC-MS/MS. Endotoxin, sterility, heavy metals, and residual solvents require separate assays (LAL/rFC for endotoxin, USP <232>/<233> for metals, USP <467> for residual solvents, USP <71> for sterility) run by labs that specialize in those methods. A vendor publishing only Janoshik results has not tested for any of these.

What is the difference between Janoshik and Freedom Diagnostics?

Janoshik is Prague-based, has roughly a decade of peptide testing history, and runs HPLC with LC-MS/MS on request. Freedom Diagnostics is Franklin, Tennessee, runs HPLC + MS as standard, publishes a large library of public COAs, and advertises a 1-2 day turnaround. For US-based buyers who want faster confirmation or a second independent reference, Freedom Diagnostics is a strong complement. For continuity with years of historical community data, Janoshik is still the baseline.

Sources

Janoshik Analytical official site and methodology overview: https://janoshik.com/about-us/

Janoshik Analytical public COA verification portal: https://public.janoshik.com/

Finnrick Analytics testing methodology and scoring: https://www.finnrick.com/about/testing-methodology

Freedom Diagnostics Testing, Franklin TN, COA verification: https://freedomdiagnosticstesting.com/

FDA Guidance for Industry: Q2(R2) Validation of Analytical Procedures, finalized March 2024 (ICH harmonized): https://www.fda.gov/regulatory-information/search-fda-guidance-documents/q2r2-validation-analytical-procedures

ISO/IEC 17025:2017, General requirements for the competence of testing and calibration laboratories: https://www.iso.org/standard/66912.html