PEPTWORKS
Technical guide

What is a peptide CoA and how to read it

What a peptide Certificate of Analysis (CoA) is, what it includes (HPLC, purity, heavy metals) and how to interpret it to sell with confidence.

What a CoA is

The Certificate of Analysis (CoA) is the document that certifies the identity and purity of a product batch. It is the objective proof of quality that separates a serious supplier from one that sells blind.

What it must include

At minimum: batch identification, HPLC analysis (purity %), and heavy-metals analysis. Ideally also identity by mass spectrometry. Acceptable purity is usually ≥98%.

How to read it

Check that the batch number matches your product, that HPLC purity meets the threshold and that heavy metals are within limits. A CoA verifiable by batch number lets you show it to your own customers.

Frequently asked questions

What purity is acceptable in a research peptide?

Generally ≥98% by HPLC, though it depends on the peptide and application.

Is the CoA per batch?

Yes. Each batch must have its own CoA verifiable by batch number; a generic certificate is not enough.