How to Read a Peptide Certificate of Analysis (COA)
A short guide to what a Certificate of Analysis actually tells you — and what to check before you trust a vial.
A Certificate of Analysis (COA) is the document that tells you what is actually in a research peptide vial. Here is how to read one.
HPLC purity
High-Performance Liquid Chromatography (HPLC) separates the components of a sample and reports purity as a percentage. A higher figure means fewer impurities. The chromatogram itself — the trace of peaks — shows whether the main peak is clean.
Mass spectrometry (identity)
HPLC tells you how pure a sample is; mass spectrometry (often LC-MS) confirms that the compound is what it claims to be by measuring its molecular mass. Purity and identity together are what give you confidence in the material.
What to check on any COA
- Is the test from an independent third-party laboratory?
- Does it list the HPLC purity figure and show the chromatogram?
- Is molecular identity confirmed (mass spec)?
- Can you see the COA before you order?
See published Certificates of Analysis in the COA library.
View COA libraryFrequently asked questions
- What does HPLC purity tell me?
- It reports the proportion of the sample that is the target compound versus impurities, as a percentage, based on chromatographic separation.
- Why does mass spectrometry matter?
- It confirms the molecular identity of the compound — that the material is actually what the label says — which HPLC purity alone does not establish.
Related reading
How to choose a peptide supplier
The checklist serious researchers use to separate a credible research supplier from a storefront — COA transparency above all.
Compound guideRetatrutide
What retatrutide is, why it is of growing interest in laboratory research, and what Australian researchers should look for when sourcing it.
LegalityAre peptides legal in Australia?
A plain-English explainer on how research peptides are positioned in Australia and what "research use only" actually means.
Last updated 31 May 2026. This article is general information for researchers, not medical or legal advice.