How to Read a COA (Certificate of Analysis)

A Certificate of Analysis is the lab report attached to a legal cannabis product. It covers four things: cannabinoid potency, the terpene profile, contaminant screening, and the lab and date that produced it. Together they let you verify both how strong a product is and whether it is safe to consume.

Start with the header. Is the lab accredited, and is the test recent? A COA from a year ago or an unnamed lab is a red flag. Reputable brands link a current, legible COA right from the product page; if you cannot find one, treat that as an answer in itself.

For potency, look at total THC and total CBD, and notice whether THCA is listed separately, since labs combine it into the total using a conversion factor. The terpene section is where quality hides — a rich, varied panel usually signals a more enjoyable product than a sky-high THC number with flat terpenes.

Then check the safety screens: pesticides, heavy metals, residual solvents, and microbials should all read "pass." This section is the whole point of testing. A product can be potent and still fail a contaminant screen, which is exactly the kind of thing the marketing will never tell you.