What Janoshik Testing Actually Tells You (And What It Doesn’t)

By NorthPeptide Research Team  |  May 6, 2026

Who Is Janoshik?

Janoshik Analytical (janoshik.com) is a Czech Republic-based analytical chemistry laboratory that has become the dominant third-party testing service in the peptide and research chemical industry. They accept customer-submitted samples — meaning individuals and vendors can mail compounds directly to their facility — and return a formal analytical report, typically within 1–3 weeks.

The lab’s prominence in the research peptide community stems from a few factors: they accept small quantities, they test compounds that many Western labs will not handle due to regulatory concerns, their turnaround is reasonable, and their reports are publicly searchable on their website — meaning anyone can look up a test result by ID number and verify it wasn’t fabricated.

This last feature is genuinely valuable. A vendor who links to a Janoshik report ID that appears in the public database is providing something verifiable. A vendor who shows you a PDF without a corresponding public record is not.

What Janoshik Actually Tests

HPLC Purity Analysis

The core test Janoshik performs is High-Performance Liquid Chromatography (HPLC). This technique separates the components of a sample by passing it through a column with a specific stationary phase, then detects each component as it elutes. The result is a chromatogram — a graph showing peaks that correspond to different compounds in the sample.

From HPLC, a lab can determine:

• Purity percentage: The target compound’s peak area divided by total peak area, expressed as a percentage. A result of “98.2% purity” means 98.2% of the detectable material in the sample is the target compound. The remaining 1.8% consists of other compounds — which may be synthesis byproducts, degradation products, or related impurities.
• Presence of major impurities: Peaks that appear at unexpected retention times indicate foreign compounds. A skilled analyst can often identify what they are; sometimes they remain unidentified.

Identity Confirmation

HPLC alone cannot confirm identity — it only measures what elutes at a given retention time. Identity confirmation typically requires Mass Spectrometry (MS) to measure the molecular weight of the compound and compare it against a known reference. Many Janoshik reports include LC-MS data, which provides this confirmation: the compound’s measured molecular weight matches the expected weight for the claimed peptide.

When a Janoshik report shows both HPLC purity and LC-MS identity confirmation, it is providing meaningful analytical evidence that:

1. The primary compound in the sample is what it claims to be (confirmed by mass)
2. The sample contains a high percentage of that compound (confirmed by purity %)

This is genuinely useful. It answers the most basic fraud question: is this vial actually BPC-157, or is it something else entirely?

What Janoshik Does NOT Test

This is where most buyers misunderstand the limits of third-party testing. A Janoshik purity certificate does not tell you:

Endotoxin Levels

Bacterial endotoxins (lipopolysaccharides, or LPS) are byproducts of gram-negative bacterial contamination during manufacturing. Even in trace amounts, endotoxins can cause serious pyrogenic (fever-causing) reactions in mammals. The standard test for endotoxins is the Limulus Amebocyte Lysate (LAL) assay — a completely separate test from HPLC.

A peptide can be 99.5% pure by HPLC and still contain endotoxin levels that would make it unsafe for injection. Janoshik does not routinely perform LAL testing. Their standard certificate does not speak to endotoxin content at all.

Sterility

HPLC cannot detect microbial contamination — bacteria, fungi, or other biological contaminants in the sample. Sterility testing requires incubation of the sample in growth media under controlled conditions, then observation over time. This is standard for pharmaceutical-grade injectables but is not part of Janoshik’s standard testing service.

A lyophilized peptide vial that tests at high HPLC purity may still contain viable microorganisms introduced during manufacturing, packaging, or shipping. Reconstituting a contaminated sample with bacteriostatic water does not sterilize it — it simply prevents bacterial growth after reconstitution.

Heavy Metal Content

Synthesis of peptides involves reagents and catalysts that can introduce trace metals — lead, arsenic, cadmium, mercury — into the final product. Detecting these requires Inductively Coupled Plasma Mass Spectrometry (ICP-MS), a separate instrument and procedure from HPLC. Janoshik does not routinely include ICP-MS analysis in standard peptide reports.

Correct Dosing and Fill Volume

HPLC measures purity of the sample submitted, not whether the vial contains the claimed amount in milligrams. A vendor could fill vials with 2mg of 98% pure peptide and claim they contain 5mg. Quantitative analysis — measuring absolute quantity, not just relative purity — requires a different protocol than standard HPLC.

The Customer-Submission Problem

A structural limitation of Janoshik testing that receives little attention: anyone can submit any sample, claim it is a specific product, and receive a certificate. The test is performed on whatever is in the vial submitted — not on the product as it exists in a vendor’s warehouse.

This creates an obvious integrity gap. A vendor could submit a high-purity sample for testing and then ship customers a different product. This is not a hypothetical — selective testing of best batches while shipping lower-quality stock is a known practice in low-transparency industries.

The countermeasure is batch-level traceability: the COA should reference a specific lot number that can be matched to the customer’s vial. If a vendor cannot tell you which batch your vial came from and show you the corresponding COA for that batch, the COA provides less assurance than it appears to.

How to Read a Janoshik Report

When evaluating a Janoshik certificate, look for these elements:

1. Report ID and public database link: Verify the report ID at janoshik.com. If it doesn’t appear in their public database, it may be fabricated.
2. Sample description: Does it match the product you purchased? Look for the peptide name and lot or batch number.
3. Test method: HPLC-UV or HPLC-DAD for purity. LC-MS for identity. Both together is the strongest combination.
4. Purity percentage: Industry standard for research-grade peptides is ≥98%. Values below 95% should raise questions. Values above 99.5% on a complex peptide warrant scrutiny — this can occasionally reflect measurement conditions rather than genuine purity.
5. Chromatogram: The actual graph matters. A clean chromatogram shows one dominant peak with minimal or no visible secondary peaks. Multiple substantial secondary peaks indicate impurities even if the purity percentage appears acceptable.
6. Mass spectrum: The measured molecular weight (m/z value × charge state) should match the theoretical molecular weight of the claimed peptide within instrument tolerance (typically ±1 Da).
7. Date of testing: An old COA on a new product is a red flag. Testing should be recent relative to manufacturing date.

Why Vendor-Side Testing Matters Too

Because customer-submitted third-party testing has inherent integrity limitations, the most trustworthy vendors combine external testing with internal quality controls:

• Testing at the synthesis source: The Chinese or Indian manufacturer who produces the raw peptide typically performs in-house HPLC before export. Reputable vendors receive and review these certificates as part of their procurement process.
• Independent re-testing on receipt: Before selling, a quality-conscious vendor re-tests incoming product through a third party using a sample drawn from the actual received batch — not from a sample the manufacturer provided.
• Endotoxin testing: Vendors who perform LAL testing on their injectables are providing a meaningfully higher level of safety assurance than those who rely solely on HPLC purity.
• Batch documentation: Lot numbers on vials that tie to documented COAs on file — accessible to customers — create a chain of traceability that eliminates the cherry-picking problem.

NorthPeptide’s Testing Approach

At NorthPeptide, every product in our catalog has a third-party HPLC certificate accessible on the product page. Our certificates are tied to specific lot numbers — the lot number on your vial corresponds to a specific COA in our records. We do not post a single certificate and rotate stock without updating it.

We are transparent about what our testing covers and what it does not. HPLC purity and identity confirmation are the standard we provide on every product. We continue to expand our testing protocols because we believe the industry standard is not sufficient — and we want our customers to know exactly what they are getting.

The Practical Takeaway

Janoshik testing is genuinely useful. In an industry where fraud is common, a publicly verifiable report confirming peptide identity and purity is meaningful information. Do not dismiss it.

But understand what it is: a purity and identity test on a submitted sample. It is not a sterility certificate, not an endotoxin test, not a heavy metals screen, and not a guarantee that the vial you receive came from the same batch as the tested sample.

The right way to use Janoshik data: as one data point in a broader quality evaluation, not as the final word on whether a product is safe or legitimate. A vendor who has a Janoshik COA has done something — but not everything. Ask what else they do before you decide how much to trust them.

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References

1. United States Pharmacopeia. <85> Bacterial Endotoxins Test. USP-NF. 2023. Available at: usp.org.
2. International Council for Harmonisation. Q6A: Specifications — Test Procedures and Acceptance Criteria for New Drug Substances and New Drug Products. ICH Harmonised Guideline. 1999.
3. Roses JB. HPLC method development considerations for peptide analysis. J Liq Chromatogr Relat Technol. 2012;35(7):998–1024.
4. Snyder LR, Kirkland JJ, Dolan JW. Introduction to Modern Liquid Chromatography. 3rd ed. Wiley; 2010.
5. Rouessac F, Rouessac A. Chemical Analysis: Modern Instrumentation Methods and Techniques. 2nd ed. Wiley; 2007. Chapters on HPLC and mass spectrometry.