If you buy research peptides, the single most important document is the Certificate of Analysis (COA) – and most suppliers either hide it, fake it, or issue it themselves. This guide explains what a COA actually tells you and how to read one, so you can judge any supplier (including us) on evidence rather than marketing.
Research use only. This is educational information about testing documentation for laboratory research materials.
What a COA is
A Certificate of Analysis is a lab report that verifies what’s actually in the vial. For a research peptide, a good COA answers two questions:
- Identity – is this actually the compound on the label? (Confirmed by mass spectrometry.)
- Purity – how much of the contents is the target compound vs impurities? (Measured by HPLC.)
HPLC purity, explained
HPLC (High-Performance Liquid Chromatography) separates the contents of a sample into its components and measures the proportion of each. The result is a purity percentage – e.g. “99.887%” means 99.887% of the peptide content is the target compound, with the remainder being related impurities.
For research, purity matters because impurities are uncontrolled variables. A peptide at 80% purity introduces 20% of unknowns into an experiment – which makes any result unreliable.
Mass spec (identity)
Mass spectrometry measures the molecular weight of the compound and confirms it matches the expected weight for that peptide. This is how a COA proves the vial contains what the label claims – not a cheaper substitute.
How to read a COA in 30 seconds
- Compound name + batch number – matches the product and links to a specific production lot.
- HPLC purity % – higher is better; look for the chromatogram (the graph), not just a number.
- Mass spec result – the observed mass should match the theoretical mass.
- Testing lab – who ran the test (see below).
- Date – recent, and tied to the batch you’re buying.
The part most suppliers hope you ignore: who tested it
There are two kinds of COA:
- Supplier-issued – the seller tests their own product and grades themselves. Easy to fake, impossible to verify.
- Independent third-party – an accredited outside lab (such as Janoshik Analytical, widely used across the research-peptide industry) tests the product. There’s no conflict of interest.
Always ask for an independent COA. If a supplier can only show a self-issued certificate – or none at all – you have no way to trust the data you generate with their product.
How Vero Labs does it
Every Vero Labs batch is tested by Janoshik Analytical, an independent third-party lab. The full COA – HPLC purity and mass-spec identity – is available for every product (a recent Retatrutide batch verified at 99.887%). We publish independent results because your research is only as reliable as the material behind it.
Browse COA available research peptides ->
Research use only. Not for human or animal consumption. Not a medicine and not intended for therapeutic, diagnostic, or medicinal use.