A strain labeled “28% THCA” on a website tells you what the brand claims. A Certificate of Analysis tells you what an independent lab actually found. Those numbers don’t always match. A 2025 compliance audit reported by Yahoo Finance found that 74% of tested hemp edibles either failed potency accuracy or contained unlisted ingredients. The flower market isn’t immune to the same problem.
If you can read a COA, you can verify every claim a brand makes before spending a dollar. If you can’t, you’re trusting labels in an industry where labels lie more often than they don’t.
This guide teaches you to read the five sections of a THCA flower COA in under five minutes, using real examples from Exhale Wellness lab results. By the end, you’ll know exactly how to calculate actual potency, verify legal compliance, check for contaminants, and spot the red flags that signal a product worth avoiding.
Section 1: The Cannabinoid Panel (What You’re Actually Smoking)
The cannabinoid panel is the first section on every COA and the one most buyers look at. It lists the concentration of each cannabinoid detected in the tested sample, expressed as a percentage of dry weight.
The numbers that matter for THCA flower:
THCA percentage. This is the raw potency of the flower before heat is applied. Quality THCA flower typically tests between 20% and 35%. Snow Caps and other isolate-enhanced products can reach 40%+. Anything below 15% is considered low-grade for smokeable flower in 2026.
Delta-9 THC percentage. This must be below 0.3% for the product to be legally classified as hemp under the 2018 Farm Bill. Even a fraction above 0.3% makes the product federally non-compliant. Always check this number. A strain at 0.28% Delta-9 is legal. A strain at 0.32% is not, regardless of how close it is.
Total THC (the number that predicts your experience). This is what you’ll actually feel when you smoke or vape the flower. The formula is standardized across the industry:
Total THC = (THCA × 0.877) + Delta-9 THC
The 0.877 multiplier accounts for the molecular weight lost during decarboxylation, the chemical process where heat strips a carboxyl group from the THCA molecule, converting it to Delta-9 THC. You lose approximately 12.3% of the weight in that conversion.
Practical example: A strain testing at 28% THCA and 0.25% Delta-9 THC has a total THC of: (28 × 0.877) + 0.25 = 24.56% + 0.25 = 24.81% total THC. That’s the potency equivalent of premium dispensary-grade cannabis.
Minor cannabinoids. Good COAs also list CBG, CBN, CBC, CBD, and other minor cannabinoids detected. These contribute to the entourage effect and give you information about the flower’s overall character. A strain with 1%+ CBG may produce more focused, alert effects. A strain with detectable CBN may lean more sedative. A strain with 0.5%+ CBD may feel smoother and less anxiety-prone.
What Exhale’s COAs show: Every THCA flower strain in the Exhale lineup includes a full cannabinoid panel listing THCA, Delta-9 THC, total THC, CBD, CBG, CBN, CBC, and total cannabinoids. The lab reports are batch-specific and publicly accessible on the Lab Testing page.
Section 2: The Terpene Profile (What It Tastes and Feels Like)
Terpenes are aromatic compounds that determine flavor, aroma, and, according to the entourage effect hypothesis, modulate the cannabinoid experience. Not all COAs include terpene testing, but quality ones do.
What to look for:
Total terpene percentage. Quality flower typically ranges from 1% to 4%. Higher generally means louder aroma, more complex flavor, and a more nuanced effect profile. Below 1% suggests the flower was poorly cured, improperly stored, or grown from low-quality genetics.
Dominant terpene identification. The top 2 to 3 terpenes by concentration determine the flower’s character more than the strain name does.
| Dominant Terpene | Aroma | Associated Effects |
|---|---|---|
| Myrcene | Earthy, herbal, musky | Relaxation, body heaviness, sedation |
| Limonene | Citrus, lemon, orange | Mood elevation, energy, stress relief |
| Caryophyllene | Pepper, spice, woody | Anti-inflammatory, calm without sedation |
| Pinene | Pine, sharp, fresh | Alertness, focus, respiratory opening |
| Linalool | Floral, lavender | Anxiety reduction, gentle sedation |
| Humulene | Hoppy, earthy | Appetite suppression, anti-inflammatory |
A strain’s COA terpene profile is a better predictor of its effects than its indica/sativa classification. Two “indica” strains with different dominant terpenes can produce meaningfully different experiences.
Practical example: Exhale’s Space Junky strain shows a limonene-forward terpene profile on its COA, which explains why independent reviewers describe it as uplifting and energetic despite its hybrid classification. The COA tells you what to expect before the jar is opened.
Section 3: The Safety Panels (What Should NOT Be in Your Flower)
This is arguably more important than potency. A 30% THCA strain contaminated with pesticide residue is worse than a 20% strain that tests clean. Safety panels check for substances you’d be inhaling directly into your lungs.
Pesticides
Hemp flower is an agricultural product subject to the same pest pressures as any crop. Pesticide screening tests for dozens of compounds including fungicides, insecticides, and growth regulators. The acceptable result is “none detected” or “below action limits” for every compound tested.
Red flag: Any pesticide detection at or above action limits. There is no “acceptable amount” of pesticide residue in flower you plan to combust and inhale. If a COA shows detectable pesticide levels, skip the product entirely.
Heavy Metals
Hemp is a bioaccumulator, meaning it absorbs heavy metals from soil more readily than many crops. COAs test for the “big four”: lead, mercury, arsenic, and cadmium. Each has established action limits (maximum acceptable concentrations).
Red flag: Any heavy metal at or above its action limit. Even below-limit results at the higher end warrant scrutiny, particularly for daily-use products where exposure accumulates.
Residual Solvents
Primarily relevant for extracts and vape products, but some flower COAs include solvent testing to confirm no post-harvest processing (chemical washing, extraction residue) occurred. Results should show “none detected” for all solvents.
Microbial Contamination
Tests for mold, yeast, E. coli, Salmonella, and total aerobic microbial count. Flower with elevated microbial counts may have been improperly dried, stored in humid conditions, or grown in unsanitary environments.
Red flag: Any pathogenic detection (E. coli, Salmonella). For total yeast and mold, results should be well below the action limit, not just barely passing.
Section 4: Lab Accreditation (Is the Lab Legitimate?)
The COA is only as trustworthy as the lab that issued it. Two credentials matter.
ISO/IEC 17025 accreditation. This is the international standard for testing laboratory competence. It requires documented quality management systems, validated analytical methods, proficiency testing, and ongoing audits. A lab with this accreditation has been independently verified to produce reliable results.
DEA registration (for labs handling Schedule I substances). While hemp is legally distinct from marijuana, some analytical methods require DEA-registered facilities.
How to verify: The lab name and accreditation number should appear on the COA. Cross-reference the lab on the accrediting body’s public database. If the lab isn’t accredited, the COA has no independently verified validity.
What some brands do instead: Self-testing (the brand tests its own product with no independent verification), using non-accredited labs (cheaper testing, less reliable results), or publishing COAs from one batch while selling a different batch. Exhale Wellness uses ISO-accredited third-party labs for every batch and publishes results on the Labs page where batch numbers can be matched to product packaging.
Section 5: Batch Information (Is This COA for THIS Product?)
A COA is batch-specific. It tells you what was in the sample the lab tested on the date it was tested. Three pieces of information connect the COA to the product in your hands.
Batch/lot number. This should appear on both the COA and your product packaging. If they match, the COA applies to your specific product. If they don’t, you’re looking at test results for a different production run.
Test date. Flower degrades over time. A COA dated 12+ months ago may not reflect the current cannabinoid or terpene content of the product, especially if storage conditions varied. COAs should be recent, ideally within the past 6 months.
Sample description. Confirms the lab tested the correct product type (flower, not trim; the correct strain name). Mismatches here suggest administrative errors or, worse, intentional mislabeling.
The 60-Second COA Checklist
When evaluating any THCA flower product, run through these checks in order.
Check 1: Is the lab ISO/IEC 17025 accredited? If no, stop here.
Check 2: Does the batch number on the COA match the product packaging? If no, the COA doesn’t apply to your product.
Check 3: Is Delta-9 THC below 0.3%? If no, the product isn’t legally hemp.
Check 4: What’s the THCA percentage? Calculate total THC: (THCA × 0.877) + Delta-9 THC. Does this match the potency the brand advertises?
Check 5: Are all safety panels present (pesticides, heavy metals, microbials)? If any panel is missing, the COA is incomplete.
Check 6: Do all safety panels show “pass” or “none detected”? Any failure is a non-negotiable reason to skip the product.
Check 7: Is there a terpene profile? Not required but indicates a higher level of transparency and quality commitment.
If a product passes all seven checks, the COA supports the purchase. If it fails any check, your money is better spent elsewhere.
Why Some Brands Don’t Publish COAs (And What That Tells You)
Full-panel testing from an accredited lab costs $200 to $500 per batch. For brands producing dozens of batches annually, this represents a meaningful expense. Brands that skip testing aren’t just cutting a cost. They’re removing the only independent verification that their product is what they say it is.
The reasons brands withhold COAs usually fall into three categories. The product failed a panel and the brand doesn’t want you to see it. The product was never tested, and the potency claims on the label are unverified. Or the brand tested one batch months ago and applies that old COA to everything they sell regardless of batch variation.
Any of these scenarios means you’re consuming a product with no verified potency, no confirmed safety, and no legal compliance documentation. In a market where 74% of tested products failed accuracy checks, the absence of a COA isn’t a minor oversight. It’s a decision to keep you uninformed.
Where to Find Exhale’s Lab Results
Every Exhale Wellness product, across THCA flower, pre-rolls, vape carts, gummies, and tinctures, publishes batch-specific COAs from ISO-accredited labs. Results include full cannabinoid panels, terpene profiles, and complete safety screening (pesticides, heavy metals, residual solvents, microbials).
Access them at exhalewell.com/labs. Match the batch number on your product to the corresponding COA. Every number on the label has a lab report behind it.
Frequently Asked Questions
What does THCA percentage mean on a COA?
It’s the concentration of tetrahydrocannabinolic acid in the flower by dry weight before heat is applied. THCA is non-psychoactive. When smoked or vaped, it converts to Delta-9 THC at a 0.877 ratio. A 25% THCA flower delivers approximately 21.9% THC when consumed.
Why does total THC matter more than THCA percentage?
Total THC = (THCA × 0.877) + Delta-9 THC. This is the actual potency you experience after decarboxylation. THCA percentage alone overstates effective potency by about 12.3% because of the molecular weight lost during conversion.
What if a brand’s COA doesn’t include safety testing?
A COA showing only cannabinoid potency without pesticide, heavy metal, and microbial panels is incomplete. Potency-only testing is cheap and easy. Safety testing is what actually protects you. Treat a potency-only COA the same way you’d treat no COA at all.
How often should COAs be updated?
Every new production batch should have its own COA. For flower specifically, cannabinoid and terpene content can vary between harvests of the same strain. A COA older than 6 months may not reflect the product’s current composition.
Can I trust COAs from brands I’ve never heard of?
Trust the lab, not the brand. Verify the lab’s ISO/IEC 17025 accreditation independently. Check that the batch number matches. Confirm all safety panels are present and passing. If the lab checks out and the results are complete, the COA is credible regardless of brand recognition.
Bottom Line
A COA is a five-minute read that separates verified quality from unverified claims. The cannabinoid panel tells you what you’re consuming. The terpene profile tells you how it’ll taste and feel. The safety panels confirm nothing harmful is coming along for the ride. The lab accreditation confirms the results are real. And the batch number confirms they apply to the actual product in your hands.
In an industry where three-quarters of tested products fail accuracy checks, reading the COA before you buy isn’t paranoia. It’s the minimum standard of informed purchasing. Every brand that deserves your money makes this easy. Every brand that doesn’t should make you wonder why.
Disclaimer: This article is for educational purposes. COA interpretation does not constitute medical, legal, or regulatory advice. THCA converts to Delta-9 THC when heated and produces psychoactive effects. Products appear on drug tests. Legal under the 2018 Farm Bill when hemp-derived. P.L. 119-37 changes effective November 12, 2026 may alter compliance calculations. State laws vary.