How to read a certificate of analysis
A certificate of analysis (COA) is the laboratory report for one production lot. Every box we ship carries a lot number, and the COA library lists the report for each lot.
Match the lot first
The lot number on the box label should match the lot number on the COA. A COA for a different lot tells you nothing about the box in your hand. Share the COA for the exact lot you sold, unedited.
What each section means
| Section | What it tells you | What to look for |
|---|---|---|
| Sample or product name | Which compound and strength was tested | Same name and strength as the box |
| Lot or batch number | Which production run | Same lot as the box |
| Test date | When the sample was analyzed | Recent. Comparison sites expect reports on popular products to be about 6 months old or newer |
| Laboratory | Who ran the test | An independent lab, named on the report |
| Identity (mass spectrometry) | Whether the measured molecular mass matches the expected compound | "Conforms" or a measured mass close to the expected value |
| Purity (HPLC) | The share of the sample that is the target compound | A percentage, often 98% or higher for peptides |
| Net content | How much material is in the vial | Close to the labeled strength |
| Other tests, when listed | Endotoxin, sterility, heavy metals | Results within the limits printed on the report |
Common questions
Why is net content slightly different from the label? Weighing and analysis carry a tolerance. Small differences are normal; the report shows the measured value.
Can I put the COA on my site? Yes, for the lot you sell, as an unedited file. Do not crop out the lab name or lot number.
What the COA does not say. A COA describes the material in the vial. It is not a statement that the material is safe or suitable for people or animals, and it must never be presented that way.
All products are sold for laboratory research use only. Not for human or veterinary use.