Understanding Certificates of Analysis

What a COA is supposed to prove

A certificate of analysis is the document that connects a specific physical lot to specific laboratory results. Two claims matter: identity — is this molecule what the label says — and purity — what proportion of the material is that molecule.

Reading the document

Lot number

This is the first thing to check, and the most commonly faked. The lot on the certificate must match the lot printed on your vial. A COA that does not name a lot proves nothing about the vial in your hand.

HPLC chromatogram

High-performance liquid chromatography separates the sample by component. You want one dominant peak with a clean baseline. The purity figure is the area of that peak as a percentage of total peak area. Look at the actual trace, not just the number printed underneath it — a shoulder on the main peak or a cluster of small peaks tells you something the summary line does not.

Mass spectrometry

MS confirms identity by measuring molecular weight. The observed mass should match the theoretical mass for the sequence within a small tolerance. If purity is high but the mass is wrong, you have a very pure sample of the wrong compound.

Test date and laboratory

The certificate should name the testing laboratory and the date. An undated certificate, or one from an unnamed lab, is not verifiable.

Warning signs

• No lot number, or a lot that does not match the vial
• A stated purity with no chromatogram behind it
• The same certificate reused across visibly different products
• Results from the manufacturer with no independent verification
• Purity claims of 100% — real HPLC does not produce that number

How we handle it

Every Viva Peptides lot is tested by an independent laboratory before release. The full certificate — chromatogram, mass spec and all — is published on the product page and in our Lab Results library. If you want to read the data before you order, it is already public.