How to Read a CBD Certificate of Analysis

A certificate of analysis, or COA, is a lab document showing what an independent laboratory found in a specific batch of product. It is the single most useful thing you can look at before buying, and most people never open one. ## Check the batch number first The batch or lot number on the COA should match the number printed on the package in your hand. A brand that publishes one COA for an entire product line rather than per batch is not really testing per batch. ## Check the date A COA more than a year old tells you about a batch that is probably no longer on the shelf. ## Read the cannabinoid panel The potency table lists each cannabinoid and how much of it the lab found. Compare the total CBD figure against what the label claims. Anything within about 10% is normal manufacturing variance. A 40% gap is not. Check the delta-9 THC line. For a hemp product sold in the US this must be below 0.3% by dry weight. ## Look for the other panels Potency alone is the easy half. A full panel also covers pesticides, heavy metals, residual solvents and microbials. Hemp is a bioaccumulator, meaning it draws contaminants out of the soil it grows in, so heavy metal testing genuinely matters. If a brand only publishes potency, ask why. ## Check who did the testing The lab should be independent of the brand and ideally ISO 17025 accredited. The accreditation number is usually printed in the header.