A COA is the paper trail behind a “tested” claim: a lab report for one specific batch. Complete ones follow a pattern you can learn in one read.
A COA is a batch-specific lab report: what was measured, the method used, the measured value, and the limit it’s compared against, usually on a single page. A document called a COA that shows conclusions without measured values is a summary, not a report.
A complete panel covers four things. Identity: the material is what the label names. Potency: the measured percentage of the label claim. Heavy metals: lead, arsenic, cadmium and mercury. Microbiology: yeast, mold and pathogens. Potency deserves a close look, because “98% of label claim” is a measurement while the word “pass” with no number attached is a conclusion you’re being asked to take on faith.
Heavy-metal results are the panel most often absent. When a COA is silent there, that silence is itself information; it’s where our Testing score looks first. One term worth decoding on any panel: “<LOQ” means below the limit of quantitation, too little for the test to measure, and the stated LOQ tells you how sensitive the test was.
Who issued it changes what it proves. A COA from an independent lab is verification by someone with nothing to sell. ISO 17025 accreditation is the credential to know; it means the lab’s own methods are audited. A COA issued by the manufacturer reports the company’s own results: information worth having, but a self-report. The letterhead is where the difference shows.
A real COA has measured values, an accredited lab on the letterhead, and a lot number that matches your bottle.
It describes one batch — ideally yours. A COA covers a single lot. The lot number on the report should match the one printed on the bottle; a COA with no lot number or date describes some batch, not necessarily yours.
Where to find one. Some brands print a QR code or keep a batch-lookup page; others provide COAs through support on request. “Available on request” only means something when the request actually works. A brand that publishes complete COAs batch by batch is showing its work, and it’s exactly the behavior our Sourcing score rewards.