How to Read a COA (Certificate of Analysis) Without a Science Degree

Not all cannabis is created equal, and neither are the lab results that come with it. If you’ve ever scanned a QR code on a product package or flipped through a dispensary website and seen something called a COA, you’ve already met the cannabis industry’s most important piece of paper: the Certificate of Analysis.

But what is a cannabis COA, and what are you actually supposed to do with it? Whether you’re shopping for cannabis flower, vapes, extracts, topicals, or edibles, reading a COA gives you the inside scoop on what you’re putting in your body. Here’s why that matters, and how to decode it like a pro.

A cannabis COA, short for Certificate of Analysis, is a lab report that breaks down the chemical makeup of a cannabis product. It’s issued by a licensed third-party lab (never the brand itself) and is used to verify the potency, purity, and safety of the product. Think of it as a nutritional label, but for weed.

You’ll find COA certificates of analysis attached to everything from pre-rolls to gummies to vape carts. Many brands list them online or link to them via QR code. If the brand doesn’t provide its COA for a product online or via QR code, the dispensary you shop at should have a copy on hand, as required in many legal states. COAs are typically required for legal cannabis sales in licensed markets, though the depth of testing can vary depending on local regulations and lab practices. 

And while all COAs aim to report the same general information, like cannabinoid content, terpene profile, and contaminant testing. The exact details can vary depending on the product and testing regulations.

A cannabis COA for flower will likely include water activity and moisture content, while one for a vape might include residual solvent testing. Edibles? You’ll want to double-check the cannabinoid concentrations for accuracy (and make sure that the heavy metal test came back clean).

Here’s where things get nuanced. While most cannabis COAs include similar categories, they’re not standardized across every lab. Testing requirements vary by state, and so do the types of data a lab chooses to include. Some labs only test for cannabinoids and contaminants, such as mycotoxins, while others take an extra step by analyzing terpene breakdowns or conducting visual inspections.

Even within the same brand, COAs can vary depending on the product type, testing lab, and even the individual batch. Some may include charts and color-coded results, while others stick to bare-bones tables. It all depends on how much information the lab collects and what the brand decides to publish.

That’s why it’s important to learn how to read a COA, not just glance at the numbers and hope for the best.

Whether you’re a seasoned consumer or trying cannabis for the first time, reading the COA weed report helps you make informed decisions. A proper cannabis COA can confirm if a product has the cannabinoid levels you’re looking for and the presence of minor cannabinoids (like CBG or CBC), ensure there are no harmful contaminants, and verify the product’s potency so you know exactly how strong it is.

This is especially important for medical consumers or anyone with sensitivities. Knowing what’s in your cannabis products and what isn’t is a form of harm reduction. COAs also help hold cannabis brands accountable. If something’s off, the data is right there in black and white.

Most licensed cannabis products will include a brief breakdown of the cannabis Certificate of Analysis on the product packaging. Some brands may print a QR code on the label or publish it on their website, linked to the product’s specific batch number. If you can’t find a COA easily by asking your budtender, that’s a red flag. You have the right to know what’s in your cannabis products.

So you’ve got the COA, great. Now what? Let’s break down each section so you know exactly how to read a COA and what to look for.

The top section of a cannabis Certificate of Analysis (COA) should list the product name, batch or lot number, and a unique sample ID. This information connects the lab results to the exact product you’re holding. It should also include the batch size and sample size, details that help assess the test’s representativeness.

For products in regulated markets, look for a METRC ID or track-and-trace identifier to confirm state compliance. The product type (e.g., flower, concentrate, edible) should also be listed to ensure the lab report matches what you’re consuming. If any of this information is missing or mismatched, it’s worth questioning the validity of the COA.

A complete COA should include the name and license number of the manufacturer, cultivator, or distributor responsible for the product. This information helps confirm that the product came from a licensed, traceable source, allowing consumers or regulators to follow up if issues arise.

You may also see additional details, such as the harvest date, packaging date, or lot number, which can help verify freshness and ensure the Certificate of Analysis (COA) matches the product in hand. If this information is missing or unclear, that’s a red flag for transparency and accountability.

Always look for a lab that’s accredited to the ISO/IEC 17025 standard. This means the lab has been independently evaluated for quality and reliability. Labs without this accreditation aren’t automatically suspect, but it’s better to work with one that has been vetted.

A trustworthy cannabis Certificate of Analysis (COA) should also specify how the product was tested, listing the method for quantification used, such as High-Performance Liquid Chromatography (HPLC) or Gas Chromatography-Mass Spectrometry (GC-MS). Steer clear of COAs from in-house labs or any reports that don’t list the laboratory director, testing method, or contact information.

This is usually labeled “Cannabinoid Test Results” or “Cannabinoids.” It indicates which cannabinoids are present and their corresponding percentages. Here’s what to focus on:

• THCA vs. THC: THCA is the non-intoxicating precursor to delta-9 THC. When heated, it converts to THC, the cannabinoid responsible for the high. Your COA should report a higher delta-9 THC content if using a method that decarboxylates the product before testing (like GC-MS) and a higher THCA content if using a different method (like HPLC). The total THC content can be found by multiplying the THCA content by 0.877 and then adding the delta-9 THC content.
• CBD, CBG, CBC, and more: These non-intoxicating cannabinoids offer unique benefits and can affect your experience.
• TAC: Total Active Cannabinoids. This indicates the overall cannabinoid content of the product.

Not every cannabis COA includes this information, but if it does, it’ll be under a section labeled “Terpenoid Test Results,” “Terpene Test Results,” or “Terpenes.” These aromatic oils influence flavor and potential effects. Some common terpenes include:

• Myrcene: Relaxing and sedative.
• Limonene: Uplifting and citrusy.
• Caryophyllene: Peppery and anti-inflammatory.
• Pinene: Sharp, piney, and good for focus.

For more in-depth information on terpenes, check out Herb’s guide to cannabis terpenes and their benefits.

This section is all about protecting your health. Depending on your state regulations, a full COA should typically test for:

• Pesticides
• Heavy metals (like lead, arsenic, mercury)
• Microbial and mycotoxin contamination (mold, yeast, bacteria)
• Residual solvents (leftover chemicals from extraction, like butane)
• Foreign materials (sand, dirt, hair, insect fragments)

Each result will be marked as “Pass,” “Fail,” or “NT” (Not Tested). You always want to see “Pass” across the board. If anything fails or wasn’t tested, think twice before using that product.

Primarily found on flower COAs, this data helps assess freshness and mold risk:

• Moisture content: The ideal range is 8 to 12%.
• Water activity: Should be below 0.65 to prevent microbial growth.
• Visual inspection: Some labs include color, trichome density, or notes about the bud’s appearance.

Make sure the COA certificate of analysis includes:

• Date of analysis
• Authorized signature or lab stamp
• A QR code that links to the lab’s online database

No QR code or signature? That could mean the COA was altered, or faked altogether. Always double-check that the info matches what’s on the product packaging.

Even if a cannabis COA looks official at first glance, there are a few common red flags that could signal something’s off. Knowing what to look for can help you avoid low-quality or even unsafe products, especially in markets where regulations are still catching up with consumer safety.

Here’s what should raise an eyebrow:

If there’s no batch or lot number listed on the product or COA, it’s impossible to verify that the product in your hand matches the COA certificate of analysis. Batch numbers link laboratory data to a specific production run, enabling the tracking of consistency and potential recall. Without it, there’s no accountability.

While not all unaccredited labs are shady, ISO/IEC 17025 accreditation provides a level of assurance that the lab follows standardized testing practices. If the COA doesn’t list the lab’s name, contact information, or credentials, that’s a red flag, especially if the results seem too good to be true.

Pesticides, heavy metals, residual solvents, and microbes are not something you want in your weed. If any section of the COA lists “Fail,” the product did not meet safety standards. Even if it’s still on shelves, skip it. You deserve better.

Potency and contamination levels can change over time. If the testing date is more than a year old, the COA may not accurately reflect the product’s current chemical composition. For edibles and extracts, especially, potency degradation and microbial risk increase with age.

Look out for COAs that appear to be copied and pasted from another product, use inconsistent fonts, or list a different product name than the one you’re holding. These could be signs of a reused or altered document.