How We Verify Peptide Purity: Janoshik Testing Explained
- ✓Janoshik Analytical is an independent third-party laboratory — they have no commercial relationship with Eternal Peptides Wholesale and no financial interest in test outcomes
- ✓HPLC (High Performance Liquid Chromatography) is the primary purity test — measuring what percentage of the sample is the target compound
- ✓Mass spectrometry confirms compound identity — verifying the molecular mass matches the expected peptide sequence
- ✓Sterility, endotoxin (LAL), and heavy metals testing verify safety parameters relevant to laboratory handling
- ✓COA verification: every Janoshik report number can be independently verified by contacting Janoshik directly — you don't have to take our word for it
In This Article
Purity and identity verification is the part of the research peptide supply chain that most suppliers don't explain clearly. This page covers exactly what testing we do, how each method works, why we use an independent third-party laboratory rather than in-house QC, and how to read a Certificate of Analysis so you know what you're looking at when you receive one.
Why Third-Party Testing — and Not In-House QC
There's a straightforward reason we don't test our own compounds and call it a day: a supplier testing their own products has a financial interest in the results. That's not a criticism of any specific supplier — it's just how conflicts of interest work. The moment you're the one running the test on the thing you're trying to sell, the credibility of the result is structurally compromised.
Independent third-party laboratories like Janoshik Analytical have the opposite incentive structure. Their business depends entirely on producing accurate, credible results — a reputation for questionable testing would destroy their client base. They have no stake in what our products test at. They report what the instruments show.
The other practical benefit: Janoshik COAs are publicly verifiable. Each report carries a laboratory report number. Anyone can contact Janoshik directly to verify a COA against their records. You're not taking our word for it — you can check the source.
What Is Janoshik Analytical?
Janoshik Analytical is an independent, accredited analytical chemistry laboratory specialising in the testing of research compounds — including peptides, SARMs, nootropics, and other research chemicals. They've become a widely recognised standard in the research compound space precisely because their methodology is transparent, their reports are independently verifiable, and they have no commercial relationship with the suppliers whose products they test.
Janoshik uses high-end analytical instrumentation — specifically HPLC-UV systems and mass spectrometry — and publishes results in a structured Certificate of Analysis format. Researchers who are familiar with analytical chemistry will find the report format straightforward. For those less familiar with lab documentation, this page explains each element.
The Four Tests — What Each One Tells You
1. HPLC — High Performance Liquid Chromatography
HPLC is the primary purity test. A dissolved sample of the compound is pushed through a column packed with stationary phase material under high pressure. Different components in the sample interact differently with the column and mobile phase, causing them to elute (exit the column) at different times. A UV detector at the end of the column records the absorption signal as each component passes — this produces the chromatogram: a graph of signal intensity over time, with peaks corresponding to each component in the sample.
Purity is calculated by dividing the area under the target peptide's peak by the total area of all peaks in the chromatogram, expressed as a percentage. A result of 98%+ is generally accepted as research grade. A result of 95–98% is considered acceptable for many research applications but warrants attention. Below 95% is problematic.
What HPLC doesn't tell you: whether the peak you're calling your target compound is actually that compound, or a different molecule that happens to elute at the same retention time. That's where mass spectrometry comes in.
2. Mass Spectrometry — Identity Confirmation
Mass spectrometry ionises the molecules in a sample and measures their mass-to-charge ratio (m/z). The result is a mass spectrum — essentially a molecular fingerprint. For a peptide, the key output is the observed molecular weight (or multiple charge states for larger peptides), which is then compared against the theoretical molecular weight calculated from the peptide's amino acid sequence.
If the observed mass matches the theoretical mass (typically within 0.1–0.2 Da), this is strong evidence that the compound is what it claims to be. If there's a meaningful discrepancy — say, the molecular weight is off by the equivalent of a missing amino acid or an added modification — that's a red flag that warrants investigation.
Combined with HPLC, mass spectrometry gives you both purity (how much of the sample is the target compound) and identity (that the target compound is actually what it says it is). Both are necessary for a complete picture.
3. Sterility Testing
Sterility testing checks for the presence of viable microorganisms — bacteria and fungi — in the sample. This is conducted using standard pharmacopoeial methods: the sample is incubated in appropriate growth media under conditions that would support microbial growth if contamination is present, then observed for turbidity or colony formation. A result of "no growth detected" over the test period indicates the batch is sterile.
Sterility is particularly important for research peptides that will be prepared in injectable form. Microbial contamination in an injectable preparation is a serious safety hazard regardless of research context. All batches supplied by Eternal Peptides Wholesale pass sterility testing before release.
4. Endotoxin Testing (LAL Test)
Endotoxins are lipopolysaccharide (LPS) components of gram-negative bacterial cell walls. Even killed bacteria leave endotoxin behind — and endotoxin is not destroyed by standard sterilisation methods. The Limulus Amebocyte Lysate (LAL) assay detects bacterial endotoxins at very low concentrations (down to picogram levels) and is the standard pharmacopoeial method for endotoxin testing.
This matters in research because endotoxin contamination causes a strong inflammatory response and can confound biological assays in ways that are difficult to detect without dedicated testing. In animal research, endotoxin contamination is a significant confound. Knowing your batch is endotoxin-tested helps ensure your experimental results reflect your compound's activity, not an endotoxin artefact.
How to Read a Peptide Certificate of Analysis
A Janoshik COA for a research peptide will typically contain the following elements. Here's what each one means and what to look for:
Every Janoshik COA includes a report number you can use to independently verify the results. If you ever have a question about a COA on one of our products, contact us and we'll connect you with the relevant documentation directly.