How to Read a Certificate of Analysis (COA)

The label tells part of the story—the COA fills in the rest. A Certificate of Analysis is a third-party lab report that breaks down what’s actually in your cannabis product: how much THC or CBD it contains, which terpenes are present, and whether it passed safety tests for things like mold, pesticides, or heavy metals.

If you're shopping with specific effects or goals in mind, the COA helps you match products to your needs. But it’s just as useful for checking the quality and safety of what you’re using. It can confirm that a product’s claims about THC, CBD, or terpene content are accurate—and make sure you’re not unknowingly consuming contaminants.

Whether you’re looking for clean medicine, precise dosing, or consistent experiences, knowing how to read a COA gives you real insight into the product—not just the marketing.

Where to Find the COA

You won’t always see lab results printed directly on the label—but most legally sold cannabis products are required to have a Certificate of Analysis available. The most common way to access it is through a QR code printed on the packaging. Scan it with your phone and it should link to the full lab report.

If you’re shopping online, dispensaries or product manufacturers often include COA links right on the product page. You can also check the footer of the website—some brands keep a link labeled “Certificate of Analysis,” “Lab Results,” or something similar at the bottom of the page.

If you can’t find it and the company doesn’t respond to a request, that’s a red flag. A product without a COA isn’t worth guessing on.

⚠️ Red Flag: If a product has no COA available, or the batch number doesn’t match the label, skip it. Transparency matters. ⚠️

What to Look for in a COA

Most COAs follow a similar structure, even if the layout varies from lab to lab. Once you know what you’re looking at, it’s easier to scan for what matters and skip the noise. Here are the key sections to pay attention to:

Cannabinoid Profile

This is usually the first table or chart you’ll see. It lists the types and amounts of cannabinoids in the product, most often shown in milligrams per gram (mg/g) or as a percentage. Look for THC, THCA, CBD, CBDA, and any minor cannabinoids like CBG, CBN, or THCV.

For flower and concentrates, THCA is often highest—remember, it becomes THC when heated.
Products should clearly show Total THC and Total CBD, which factor in those conversions.

Terpene Profile

If included, this part of the COA shows the dominant terpenes and their percentages—usually the top 3 to 5. Terpenes contribute to both flavor and aroma, but more importantly, they shape the overall effect of the product. Some promote relaxation or sleep, others support focus or energy.

Pay attention to the top terpenes present, as they tend to guide the experience. For example, high levels of myrcene may suggest a more sedating, body-heavy effect, while limonene or pinene may lean uplifting or clear-headed.

📊 Not sure what they do? Check out our Terpene Effects Chart for a breakdown of what each one may contribute to your experience. 📊

If there’s no terpene data included, it doesn’t necessarily mean the product has none—it may just not have been tested. But for flower, vapes, and full-spectrum products, this section is worth scanning to get a clearer idea of how the product might feel.

Contaminant Screening

This section of the COA shows whether the product passed safety tests for things like pesticides, solvents, heavy metals, mold, and bacteria. This is critical for anyone using cannabis for medical reasons—or anyone who just doesn’t want harmful residue in their body. Here’s what you might see, and what to avoid:

Pesticides: Some cannabis is grown using chemicals that can leave behind toxic residues. Common ones to watch for include myclobutanil (a fungicide that can release hydrogen cyanide when burned) and bifenazate (an insecticide with known health risks). A “pass” means these were either not detected or well below safe thresholds.
Residual Solvents: Concentrates are often extracted using solvents like butane, propane, or ethanol. If not properly purged, these can remain in the final product. The COA should show ND (non-detectable) or a level below the allowed limit. Look out for butane, hexane, propane, or isopropyl alcohol.
Heavy Metals: Cannabis plants are bioaccumulators, meaning they can pull toxins from the soil. COAs typically test for lead, arsenic, cadmium, and mercury. Even in small amounts, these can be dangerous over time—especially for people with weakened immune systems.
Microbial Contaminants: Mold, mildew, and bacteria can show up in improperly stored or cured products. You don’t want to see anything like aspergillus, salmonella, or E. coli in a test result. For inhaled products especially, mold is a serious concern.
Mycotoxins: These are toxic substances produced by mold. Two to watch for: aflatoxin and ochratoxin, both of which are known to be harmful even at low levels.

What you want to see: A clean “Pass” next to each of these categories, ideally with ND (non-detectable) values. If anything shows as detected, it should be well below the legal threshold—and if it’s flagged or failed, skip that product entirely.

💡 Quick Scan Tip: Look for “Pass” on contaminants, a recent testing date, and at least a few dominant terpenes if you're shopping based on effects. 💡

Red Flags to Watch For

A COA should give you clarity—not more confusion. If something feels off or is missing, it’s worth pausing. Here are a few signs that a product might not be up to standard:

No COA Available: If there’s no Certificate of Analysis—or the brand or dispensary can’t provide one—that’s your first red flag. Transparency is non-negotiable.
Old Testing Date: Cannabinoids and terpenes degrade over time. If the testing date is more than a year old (especially for flower), the actual effects may not match the listed profile.
Mismatched Batch Numbers: Make sure the batch number on the product matches the batch number on the COA. If it doesn’t, the lab results may not apply to what you’re actually holding.
Contaminants Present or “Fail” Flags: Even if only one category shows a fail—like mold, pesticides, or heavy metals—that’s enough to skip the product. You shouldn’t have to compromise on safety.
No Cannabinoid Breakdown: Some products only list “Total THC” without showing how much of that comes from THCA or delta-9 THC. Without detail, it’s harder to know how the product was made or how it might affect you.

Why Reading a COA Matters

A Certificate of Analysis gives you more than numbers—it gives you power. Whether you're using cannabis for health, relief, or personal preference, knowing how to read a COA helps you make smarter, safer choices. It shows you what’s really in the product, how it was handled, and whether it’s worth your time (or your money).

It’s not just about effects. It’s about transparency, consistency, and confidence—especially when THC percentage alone doesn’t tell the full story.