Research tools
How to Read a Peptide COA
A Certificate of Analysis (COA) is a lab document that verifies a peptide's purity and identity. Use this checklist to confirm your COA is legitimate before placing an order. Every Polygon Peptides batch is third-party verified by Janoshik and includes a COA on request.
6 verification checks
Works with any supplier's COA
Instant pass / fail result
COA Verification Checklist
Tick each item as you confirm it on your Certificate of Analysis
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Peptide name and CAS number are clearly listed
The compound name should match your order exactly. A CAS number uniquely identifies the molecule and rules out substitution.
Identity
Testing method is HPLC
High-Performance Liquid Chromatography (HPLC) is the industry standard for peptide purity testing. Avoid COAs that only list visual inspection or basic spectroscopy.
Method
Purity result is 99% or above
Research-grade peptides should show purity of at least 99% by HPLC. Anything below this threshold introduces unacceptable variability into experimental results.
Purity
An independent third-party lab is named
The testing lab must be separate from the supplier. Self-issued COAs are unverifiable. Look for recognised labs such as Janoshik, Colmaric, or similar accredited facilities.
Lab
A batch or lot number is present
Each production run should have a unique batch number that links your product to its test data. No batch number means the COA cannot be traced to a specific production run.
Batch
Test date is within the last 12 months
A COA dated more than a year ago may not reflect current stock. Reputable suppliers test each batch individually and provide recent documentation for every order.
Date
Awaiting verification
Tick each item above as you confirm it on your COA document.
For research guidance only. This checklist is a general verification guide and does not constitute laboratory accreditation advice. Always consult the original lab report and contact your supplier directly with any concerns. Polygon Peptides provides Janoshik-verified COAs with every batch. These points reflect widely accepted standards, though lab practices may vary.