A certificate of analysis (COA) is the single most useful document when you buy a research peptide. It is also easy to fake or misread. This guide explains each part and the red flags to watch for.
1. Product name and batch number
A real COA belongs to one specific batch. It should show the product name, the batch (lot) number and the date of testing. If a supplier sends one generic COA for every batch, it tells you nothing about the vial in your hand.
2. HPLC purity
HPLC (high-performance liquid chromatography) separates the sample into its components. The report shows a chromatogram, a line with peaks. Purity is the area of the main peak divided by the total area of all peaks, usually measured at 214–220 nm, where peptide bonds absorb light. A main peak that is tall and narrow, with only tiny peaks around it, is what you want. Look for the percentage printed on the report, not just on the label.
3. Mass spectrometry (identity)
HPLC says how pure a sample is, but not what it is. Mass spectrometry measures the molecular weight. The observed value should match the theoretical one: BPC-157, for example, has a theoretical mass of about 1,419.5 Da. A COA with HPLC but no mass-spec result cannot prove identity.
4. Purity is not peptide content
A freeze-dried peptide also contains water and counter-ions (such as acetate or TFA), so the net peptide content is usually below 100% even when purity is 99%. A good report states which figure it is giving.
5. The laboratory
Check who ran the tests. A named, independent laboratory with a date and contact details is far more reliable than an unsigned page from the manufacturer.
Red flags
- No batch number, or the same document for every batch.
- Only a screenshot or an image, with no way to verify it.
- Identical “99.9%” purity on every product.
- HPLC results but no identity test.
- Missing date or laboratory name.
Our approach
At Trusted-Peptide every product page shows its purity, and we ship from Europe with cold-chain packaging. If you want to see the report for a specific batch before ordering, contact us. You can browse the full peptide catalogue or read about BPC-157 as an example.
For laboratory research use only. Not for human or veterinary consumption. This article is educational and is not medical advice.