How to Read a Peptide Certificate of Analysis (COA)

Why the COA matters

A Certificate of Analysis (COA) is the only objective evidence that the powder in a vial is what the label says, at the purity claimed. For researchers, a reliable COA protects the validity of results; for buyers, it’s the clearest way to separate trustworthy suppliers from the rest.

A good COA is batch-specific: it describes the exact lot printed on your vial, not the product in general.

1. The header: who, what and when

Start at the top. A credible report shows:

• Compound name and, ideally, its sequence or CAS number.
• Lot / batch number — this must match your vial.
• Test date and laboratory name. Independent third-party labs carry more weight than in-house testing.
• A sample or report ID that the lab can confirm if you contact them.

2. Identity: mass spectrometry (MS)

Mass spectrometry confirms what the compound is by measuring its molecular mass. The report should list the theoretical (expected) mass and the observed mass. They should match closely — typically within about one dalton for small peptides.

A mass that doesn’t match means the wrong peptide, a truncated sequence or a modified variant. This is also how you can tell, for example, a short TB-500 fragment from full-length thymosin beta-4 (see BPC-157 vs TB-500).

3. Purity: HPLC

High-performance liquid chromatography (HPLC) separates the sample into its components. Purity is reported as the main peak’s share of the total peak area — for example “99.1%”.

• Look for an attached chromatogram (the graph). A single dominant peak is what you want.
• Note the detection wavelength (often 214–220 nm for peptides) and the method.
• Purity describes the share of peptide that is the correct peptide — it is not the same as how much of the powder is peptide (next section).

4. Net peptide content vs. gross weight

Lyophilized peptide powder also contains counter-ions (such as acetate or TFA) and a little residual water. So a vial can be 99% pure yet contain slightly less than its gross weight in actual peptide. Some COAs report net peptide content or quantify the amount per vial — a strong sign of a thorough lab.

Red flags

• No lot number, or a lot number that doesn’t match your vial.
• No test date, lab name or chromatogram.
• Identical “99.9%” results across every product and every batch.
• Blurry, cropped or obviously edited PDFs.
• A supplier who won’t share COAs, or only shares them after purchase without a lot reference.

RevitaCore COAs

Every RevitaCore batch has a Certificate of Analysis. Contact us with the lot number on your vial and we’ll send the matching report. For more on choosing a supplier, read the Research Peptides in Canada buyer’s guide.

Frequently asked questions