5 min read
Reading the certificate that came with your vial
Nine things to check, in the order that catches problems fastest. The first one eliminates most of them.
A certificate of analysis is a record of what a laboratory measured in one specific batch. It is not a quality seal and it is not transferable between batches, which is where most of the trouble starts.
Start here
Check that the batch or lot number on the certificate matches the number printed on the vial you are holding. If they differ, the document describes other material, however impressive its contents. This single check catches the most common problem in the market: one good certificate, circulated for everything.
Then the rest
| What to look for | Why it matters |
|---|---|
| Batch number matching the vial | A certificate belongs to one batch. Anything else is a document about different material. |
| Date of analysis | Tells you whether the batch was tested, and when relative to when it was made. |
| The testing laboratory, by name | An unnamed lab cannot be checked, and "third-party tested" without a name is a claim about itself. |
| HPLC purity with the chromatogram | The trace shows peak separation and where the impurities sit. A bare percentage shows neither. |
| Method conditions | Column, gradient and wavelength. Without them the figure cannot be reproduced. |
| Mass spectrometry result | Measured mass against theoretical mass. Purity alone does not establish identity. |
| Appearance and solubility | Cheap to report, and a mismatch with what is in the vial is an immediate signal. |
| Water content | Lyophilised powder takes up water. It is part of the weight you paid for. |
| Net peptide content | Rarely reported. Without it, the milligrams on the label are gross weight. |
What the figures do and do not establish
A certificate speaks to analytical quality: how clean the material is and whether it is what the label says. It says nothing about safety, and nothing about suitability for any purpose. Those are different questions, and no laboratory report answers them.
Signals worth stepping back from
- A certificate only available after you have paid.
- The same certificate turning up for several batches, or no batch number at all.
- A purity figure with no chromatogram and no method conditions behind it.
- "Third-party tested" with no laboratory named.
- A document that has been flattened into an image at a resolution where the numbers cannot be read.