How to Read a Cannabis Certificate of Analysis (COA)

Every jar of legal cannabis sold in a licensed dispensary comes with a Certificate of Analysis, a lab report that tells you exactly what's in the product you're about to buy. Most consumers never look at it. The ones who do buy dramatically better cannabis.

This guide breaks down every section of a COA so you can use it confidently at the dispensary counter, on a delivery platform, or when evaluating a seed bank's genetics before your next grow.

What Is a Certificate of Analysis?

A COA is a document produced by an accredited, third-party cannabis testing laboratory. In regulated markets, licensed dispensaries are required to have COAs for every product on their shelves. The lab tests a sample from the batch and reports the results. Those results cover:

1. Cannabinoid potency (how much THC, CBD, CBG, and other cannabinoids are present)
2. Terpene profile (which aromatic compounds are present and in what concentration)
3. Safety screens (pesticides, heavy metals, residual solvents, microbial contaminants)

Think of a COA as a nutritional label, except instead of calories and sodium, it's telling you about the compounds that will shape your experience.

Multiple JointCommerce strain guides emphasize COA reading as an essential skill. Strains with ambiguous naming like Codes strains or Terps strains, where the same name is applied to products from different genetic backgrounds, are virtually impossible to evaluate without COA data.

Section 1: Cannabinoid Panel

This panel is the section most consumers look at first, usually because they want to know, "How strong is it?"

Key fields to understand:

THCA (Tetrahydrocannabinolic Acid) THCA is the non-intoxicating acid form of THC that exists in raw, unheated cannabis. When you apply heat, via smoking, vaporizing, or baking edibles, THCA decarboxylates and converts to active delta-9 THC.

Why this matters: Many labs report THCA as the primary potency marker, not delta-9 THC. When you see "28% THCA" on a label, that doesn't mean 28% of the flower is psychoactive THC in its current state. The conversion formula is:

Total THC = (THCA × 0.877) + delta-9 THC

So a flower with 28% THCA and 0.5% delta-9 THC has approximately 25% total THC after decarboxylation. That's still very potent, but the distinction matters.

Delta-9 THC: The psychoactive form of THC is already present in the flower before heating. In cured flower, this is typically low (0.5–3%). High delta-9 in raw flower can indicate over-ripeness or degradation.

CBD (Cannabidiol): Most premium recreational flower has minimal CBD (under 0.5%). Products bred specifically for CBD content will show 1–20%+ CBD. For consumers using cannabis for therapeutic purposes without strong psychoactivity, higher CBD with lower THC is worth seeking.

CBG (Cannabigerol): A minor cannabinoid that appears in trace amounts (0.2–1.2%) in most tested flower. Some strains show higher CBG, which is associated with focus and clarity in early reports. Strains like Citron and Citradelic Sunset sometimes show elevated CBG that contributes to their clear-headed effect profile.

CBC (Cannabichromene): Another minor cannabinoid. Present in small amounts (usually 0.05–0.3%). Emerging research suggests potential roles in mood support and anti-inflammatory activity, though cannabis science is still catching up.

How to interpret potency:

• Under 15% total THC: Lower potency; good for beginners or microdosers
• 15–22% total THC: Mid-range; reliable for most consumers
• 22–28% total THC: High potency; the current "premium flower" standard in most markets
• Above 28% total THC: Very high; typically the result of elite indoor growing with optimized conditions

One important caution: potency alone does not predict experience quality. A 30% flower with 0.8% total terpenes will often feel less satisfying than a 22% flower with 3.5% total terpenes. For gas-forward strains like Petrochem or Permanent Gas, the terpene panel is at least as important as the cannabinoid numbers.

Section 2: Terpene Panel

This is the section most consumers skip, and that's a mistake. Terpenes are the best predictor of how a strain will actually smell, taste, and feel.

What to look for:

Total terpene percentage:

• Under 1.0%: Low aromatic intensity; may feel flat
• 1.0–2.0%: Average for commercial premium flower
• 2.0–3.5%: High-quality, aromatic flower
• 3.5%+: Exceptional; typically only small-batch craft cultivation

Dominant terpene: The first terpene listed (highest by percentage) is the most important for predicting effect direction. Here's a quick reference:

Reading the triad: Experienced cannabis shoppers focus on the top three terpenes together. A caryophyllene + limonene + myrcene triad is common in well-rounded hybrids; you get peppery warmth, citrus lift, and a grounding body base. A myrcene, linalool, and caryophyllene triad suggests a strain that leans calming and sedative, ideal for the type of relaxation strains we cover in our best cannabis strains for relaxation guide.

For a complete breakdown of every terpene and what it signals, see the JointCommerce terpene guide.

Section 3: Safety Screens

This section is where the COA really proves its value. Legal cannabis is required to pass safety testing, but not all testing is equal, and a pass in one state may use different thresholds than a pass in another.

Pesticide screening:

Cannabis is an aggressive absorber of soil and environmental compounds. Pesticides applied during cultivation can concentrate in the flower and in concentrates. A compliant COA will show ND (Not Detected) or values below your state's action limit for all tested pesticides.

What to watch for: Some older testing panels screen for fewer pesticide compounds than newer, more comprehensive panels. A COA that tests for 50 pesticides gives you less assurance than one that tests for 200+. In legal markets like California and Oregon, regulators have expanded required pesticide panels significantly since 2020.

Heavy metals:

Cannabis grown in contaminated soil can contain elevated lead, arsenic, cadmium, or mercury. The COA will show individual metal readings against action limits. All values should be either ND or clearly below the limit.

Concentrates note: Residual heavy metals concentrate during extraction. For vape cartridges and wax/shatter products, scrutinize this section especially carefully.

Residual solvents (for concentrates):

If you're buying a wax, shatter, live resin, or distillate product, the COA should include a residual solvent panel. Common solvents used in extraction (butane, propane, and ethanol) must be purged below safe thresholds. A compliant COA shows ND or below action limits for all solvents.

Microbial contaminants:

This section tests for harmful bacteria and mold, including:

• Total Yeast and Mold Count (TYMC)
• E. coli
• Salmonella
• Aspergillus (particularly important for immunocompromised consumers)

Flower should pass all microbial limits. If you purchase cannabis and notice a hay-like smell with unusual spots on the flower, suspect an improper cure or storage, and request the microbial COA if you have concerns.

How to Access COA Data

At a dispensary: Ask the budtender directly. They should be able to pull the COA for any product. If they can't, note that limitation. As noted in our first dispensary visit guide, budtenders at quality dispensaries are trained to assist with exactly this kind of product research.

Online / delivery platforms: Many licensed platforms now include COA links directly in their product listings. When buying cannabis online, prioritize vendors who include terpene panels, not just cannabinoid data, in the listing.

QR codes on packaging: Many states require or encourage QR codes on labels that link directly to the batch COA. Scan it before purchase when possible.

Brand websites: Many premium brands post COA data by batch number on their own websites. For strains like Orange Slushie or PK Crasher, cross-referencing the brand's published COA with the dispensary's copy verifies consistency.

Common COA Red Flags

Watch out for these warning signs:

• No terpene panel: Some cheaper testing packages omit terpene testing. A cannabinoid-only COA is incomplete.
• COA date is more than 12 months old: Terpene profiles degrade over time. A COA from 18 months ago may not reflect the current state of the product's aroma or potency.
• Batch number doesn't match: The COA's batch number should match the batch number on the product packaging. Mismatches suggest the COA may not be specific to what you're buying.
• Missing safety screens: A COA that only shows cannabinoids with no pesticide, metal, or microbial data is not a full compliance COA.

Putting It All Together: A COA-First Shopping Strategy

Here's a repeatable process for using COA data in any purchase:

1. Identify what you want from this session — relaxation, creativity, energy, sleep, or social use.
2. Match your intent to a terpene target — myrcene + linalool for sleep; limonene + terpinolene for energy.
3. Ask for or find the COA — verify the terpene panel confirms your target profile.
4. Check total terpene percentage — confirm it's above 1.5% for premium quality.
5. Review the safety screens — all pesticides, metals, and microbials should pass.
6. Verify batch match — COA batch number = product label batch number.

Whether you're evaluating a strain like 3 Kings with an ambiguous origin story or a well-documented cut like Trainwreck, the COA gives you the data to make a confident, informed choice.

The Bottom Line

A COA is the most powerful tool available to a cannabis consumer in the legal market. It removes guesswork from your purchase, protects your health, and — when you know how to read the terpene panel — helps you reliably find the experience you're after.

Use the JointCommerce strain library to research cultivars before you shop, and pair that knowledge with the COA data in the dispensary. That combination, pre-research + real batch data, is the gold standard for buying cannabis in 2025.

Find dispensaries near you that provide transparent COA data through the JointCommerce directory. For more on terpenes, see our complete terpene guide.