Reading a Certificate of Analysis: A Quick Guide for Researchers
A COA is the single most important quality document that ships with a research peptide. Here's what each section actually tells you.
What a COA is
A Certificate of Analysis (COA) is a batch-specific document confirming that the supplied peptide matches the listed identity and meets the supplier's purity specification. It is your single best evidence of what is actually in the vial.
Sections to check
1. Identity confirmation — usually mass spectrometry (MS) confirming the molecular weight matches the expected sequence. Look for the calculated and observed mass.
2. Purity — typically determined by reverse-phase HPLC, expressed as a percentage. Research peptides at Peptigen Labs target ≥99% by HPLC unless otherwise noted on the listing.
3. Batch number — must match the label on the vial. If they differ, contact your supplier immediately.
4. Manufacture and retest dates — show the production date and the recommended re-evaluation date for the batch.
5. Appearance — confirms the visible state (e.g. white lyophilised cake, blue-green for copper-peptide).
6. Storage conditions — confirms recommended storage (Peptigen Labs lyophilised peptides: 2-8°C unless noted otherwise).
Red flags
Missing batch number, generic / template-style language without specific values, or a COA that doesn't match the SKU on the vial are all reasons to pause and check with the supplier before using the material.
Every visible Peptigen Labs product publishes its current-batch COA directly on the product page — download in one click from the Certificate of Analysis panel.
Researcher FAQs
What is a Certificate of Analysis (COA)?
A COA is a batch-specific document confirming that the supplied peptide matches its declared identity and meets the supplier's purity specification. It is the single best piece of evidence of what is in the vial.
What should I look for on a research peptide COA?
Six things: 1) identity confirmation by mass spectrometry, 2) purity by HPLC as a percentage, 3) batch number that matches the vial label, 4) manufacture and retest dates, 5) the appearance description, and 6) storage conditions.
How do I get the COA for a Peptigen Labs product?
Go to the product page on peptigenlabs.co.uk, scroll to the 'Certificate of Analysis' panel and click 'Download Certificate of Analysis'. The PDF saves directly to your device. Every visible product with available stock has its current-batch COA published.
What are COA red flags?
A missing batch number, generic template-style language with no measured values, or a COA whose SKU/batch doesn't match the vial label are all reasons to pause and contact the supplier before using the material.
This article describes published research literature only. It is not medical, dosing, administration, therapeutic, veterinary or human-use guidance. Peptigen Labs material is supplied strictly for laboratory research use only.