Quality & Testing
Every claim on this site about purity is backed by a laboratory report for a specific batch. This page documents what is tested, who tests it, and how you can check the result yourself — before you order.
The evidence chain
Quality claims only mean something when they can be traced. Ours follow one chain:
Batch number on the vial → the same batch number on the Certificate of Analysis → the report issued by a named independent laboratory.
Analytical results apply only to the batch that was tested, which is why every certificate we hold is batch-specific and why the batch number is printed on each vial.
What is tested, on every batch
| Test | Method | Laboratory |
|---|---|---|
| Purity | HPLC (peak-area %) | Janoshik Analytical |
| Identity | Mass spectrometry — theoretical vs observed mass | Janoshik Analytical |
| Endotoxins | LAL assay, reported in EU/mg | Janoshik Analytical |
| Heavy metals | Elemental analysis | Janoshik Analytical |
Janoshik Analytical is an independent laboratory in Prague, Czech Republic — the most widely used third-party testing laboratory in this field. We are a customer of the laboratory; it has no ownership or commercial ties to Onyx Peptides.
How to get a certificate before ordering
Email support@onyxpeptides.com with the compound you are interested in and ask for the Certificate of Analysis of the batch currently in stock. The document already exists — sending it takes minutes, not days. When your order arrives, check that the batch number on the vial matches the certificate.
Independent verification
You do not have to take the certificate on trust. Every Janoshik report carries an identifier issued by the laboratory, and the laboratory can confirm reports it issued when contacted with that identifier. A certificate that survives that check is evidence; one that cannot be verified is a picture.
Reading the results
An HPLC purity figure, a mass-spectrometry result and an endotoxin number each answer a different question, and none of them alone tells the whole story. Our guide to reading a Certificate of Analysis walks through the document line by line, and how peptide purity is verified explains what HPLC and mass spectrometry each establish.
Who stands behind this
Onyx Peptides is operated by Vexio j. s. a., a company registered in Slovakia (IČO 54214530). Orders are dispatched from within the EU — no customs border, no import delays.
All products are supplied strictly for laboratory research use. They are not for human consumption, veterinary, or clinical use.