The buying guide
Protein powder COA checklist: match the report to the bag
A useful certificate of analysis identifies the sample and reports results with units and analytical context. Start by confirming that the document covers the product you are evaluating.
Match the identity before comparing numbers
Look for the product, flavor, lot or batch identifier, laboratory, and date. If the document describes an ingredient rather than the finished powder, record that distinction. Do not silently treat an old or unrelated sample as your current bag.
Keep the original report available while making notes. Transcribing only the result column can lose less-than signs, footnotes, analyte names, or the difference between a measured value and a specification.
Read the result and its context together
For each analyte, record the stated value, unit, method, and any reporting or quantification limit. Keep total arsenic and inorganic arsenic separate if a report distinguishes them; matching the word arsenic alone is insufficient for a like-for-like comparison.
If the relationship to your package is unclear, ask the manufacturer which lot the report represents. You can use our calculator once the units and serving weight are known. It calculates an amount; it does not authenticate the report or establish compliance with a standard.