Understanding Certificates of Analysis in Peptide Research

A Certificate of Analysis (COA) is a document issued by a testing laboratory that confirms the identity, purity, and composition of a research compound. For anyone sourcing peptides for laboratory work, understanding what a COA does and does not tell you is an important part of evaluating a supplier.

What a COA Typically Includes

A standard COA lists the compound name, batch or lot number, test date, and results from analytical methods such as HPLC (high-performance liquid chromatography) for purity, and mass spectrometry for identity confirmation. Reputable third-party labs perform this testing independently of the manufacturer, which is what gives the results credibility.

Why It Matters for Research

Using compounds without independent purity verification introduces a variable into any experimental design. A COA lets researchers document what was actually used, not just what a label claims, which matters for reproducibility and record-keeping.

What To Ask Your Supplier

When evaluating a research compound supplier, it is reasonable to ask whether COAs are available per batch, which lab performs the testing, and whether documentation can be provided before or at the time of purchase.

We are currently working with our manufacturing partners to make batch-specific COAs available across our catalog and will update this page as that rolls out.