How to read a certificate of analysis

A certificate of analysis is the only part of a cannabis purchase that can be checked rather than believed. Everything else, from the cultivar name to the photograph to the description of the aroma, is a claim. The COA is a measurement, made by someone other than the seller, on a defined quantity of material. Reading one takes about two minutes once you know which fields carry weight.

A batch, not a brand

A COA is issued by a third-party laboratory for one specific batch of material. It does not certify a brand, a product line or a company; it certifies the jar of flower or the tin of extract that the sampled material came from. A second batch of the identical cultivar, grown in the same room three months later, needs its own certificate.

The header deserves as much attention as the results table. Look for the laboratory name and its accreditation reference, the date the sample was received and the date the report was issued, the batch or lot identifier, the weight of the sample tested, and who supplied it. A producer submitting its own sample is common practice, but it carries different evidentiary weight from a sample the laboratory collected itself.

Working through the panels

Potency comes first on most reports. A well-built panel lists THCA and delta-9-THC on separate lines, and CBDA and CBD on separate lines again, each as a percentage by weight. The acidic forms, THCA and CBDA, are what the plant actually produces; the neutral forms are what remains after heat, light and time have done their work. A raw THCA figure is not the number that describes what you will encounter once heat is applied.

This is why total THC is arithmetic rather than a reading. THCA loses a carboxyl group when heated, and mass goes with it, so the convention is to multiply THCA by 0.877 and add any delta-9-THC already present in the sample. A flower reporting 22 percent THCA and 0.4 percent delta-9-THC therefore carries a total THC of roughly 19.7 percent. The same 0.877 factor applies to CBDA when calculating total CBD. If a certificate prints a single THC number with no working shown, you cannot tell which convention it used.

The pesticide panel should be a named list of analytes, each with an action limit and a result assessed pass or fail against that limit. ND means not detected at the laboratory's limit of quantitation, which is a statement about the sensitivity of the method rather than a guarantee of zero. Residual solvents matter only for extracted products, where butane, propane, ethanol, hexane and benzene are the names to check against their limits; flower has no reason to carry that panel.

Heavy metals, meaning lead, cadmium, mercury and arsenic, deserve attention because cannabis is a known accumulator, drawing up what is present in soil and irrigation water. Microbial panels cover total yeast and mould, coliforms, E. coli, Salmonella and Aspergillus species, with aflatoxins and ochratoxin A reported as mycotoxins. Water activity and moisture content sit alongside them, because they govern mould risk and shelf life more directly than any other pair of numbers on the page.

What a pass actually looks like

A pass is not a green banner at the top of a page. It is every panel present, every analyte listed with both its limit and its result, and a batch identifier that matches the code printed on the jar in your hand. The report date should sit close to the packaging date, and the laboratory should be identifiable and contactable: a name, an address, a way to verify the document. If any of those are missing, the certificate is decoration.

• A potency-only certificate presented as full testing, with no contaminant panels at all
• Screenshots or cropped tables in place of the complete signed PDF
• No batch number, or a batch number that does not match the product in front of you
• A certificate more than a year old attached to a batch described as fresh
• Results printed without a limit column, so nothing can be assessed as pass or fail
• A laboratory that cannot be found, verified or contacted

Limits are local, and they move

Action limits are not universal. Each market sets its own list of regulated analytes and its own thresholds, and those lists are revised as methods improve and priorities change. A result that passes under one framework may be assessed differently under another, or not assessed at all because the analyte is not on that list. For what applies where you are, consult the legal status by country page and your own local rules rather than treating a pass mark as portable.

These documents are for adults of legal purchasing age, 21+ where we ship. Whatever the numbers say, start low and go slow, leave time before deciding to take more, and do not drive or operate machinery. Do not combine with alcohol. Keep everything locked away from children and pets, and speak to a doctor before use if you are pregnant, breastfeeding or taking medication.