How to Read a Peptide Certificate of Analysis (COA)

A certificate of analysis is a report from a testing lab saying what it found when it tested a sample. For a research peptide, that usually means what the material is, how pure it is, how much of it is in the vial, and whether it is contaminated.

A COA belongs to one lot, not to a product. A report for a different lot tells you nothing about the vial in your hand, which is why the first thing to check is not the purity figure but the lot number.

Lab name. Who ran the test. An independent lab with no stake in the result is worth more than an in-house report, and a named lab can be contacted.

Lot or batch number. It should match the lot recorded on your order or printed on your vial. If a seller shows one certificate for every lot, it is not really about your vial.

Test date. Recent is better. A two-year-old report on a product that sells out every month is describing material that is long gone.

Purity (HPLC). High-performance liquid chromatography separates the sample into its components. Purity is the share of the signal that belongs to the named compound, so 99.5% means about half a percent of what was detected was something else.

Measured content. How many milligrams of the compound the lab actually found in the vial. A 10mg label with 10.9mg measured is filled generously. A result well under the label is worth noticing, because it is the failure few sellers advertise.

Endotoxin. Reported in EU (endotoxin units) per vial, usually measured with an LAL assay. It is a measure of bacterial contamination: lower is better.

Microbial (TAMC / TYMC). Total aerobic microbial count and total yeast and mould count. A pass means the counts were under the lab's limits. It is a bioburden count, not a sterility test.

No lab name, or a lab that cannot be found. No lot number. The same PDF shown for every product or every lot. Figures with no units. A report that has clearly been edited, with mismatched fonts or cropped headers.

Many labs, Janoshik included, print a verification key on the report so anybody can confirm it on the lab's own website. If a key is printed, check it.

Every product with a published report shows its figures right on the product page, with the full PDF one click away, and every certificate we hold is listed on our COA page.