How to Read a Peptide Certificate of Analysis

A certificate of analysis (COA) is the document that turns a purity claim into something you can verify. Knowing how to read one is the single best defense against low-quality material.

Purity (HPLC): the headline number. High-performance liquid chromatography separates the sample's components; the purity percentage reflects how much of the sample is the target compound. Reputable labs report against a specification such as ≥95%.

Identity (ID): confirms the compound is what the label says, typically by comparing chromatographic retention time against a known reference standard.

Net peptide content: the actual mass of peptide in the vial, distinct from total powder mass (which can include counter-ions and water). Fentanyl screen: an immunoassay confirming the absence of fentanyl contamination — an increasingly standard safety check.

When you buy from Rising Tide, the COA for your lot ships with the order and is available on our Lab Testing page. Materials are for research use only.