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THCa vs THC: How to Read a Michigan Cannabis Label
THCa is the acid form of THC that the cannabis plant makes on its own. Heat converts it to THC, and the "Total THC" number on a Michigan label estimates how much THC a product can deliver once that conversion happens.
Written and reviewed by the Banzen Editorial Team · Updated October 20, 2026 · How we write these guides
55 S. Michigan Ave
Coldwater, MI 49036
Sunday – Saturday: 9am – 9pm
Happy Hour: 4pm – 4:30pm
THCa vs THC at a Glance
THCa
Tetrahydrocannabinolic acid, the form the plant makes and the main cannabinoid in raw flower
THC
Delta-9 THC (Δ9-THC on a COA), what THCa becomes when it's heated
Total THC
(THCa × 0.877) + delta-9 THC, the one number on Michigan labels and the Banzen menu
Why 0.877
THCa drops a carboxyl group as it converts, so a gram of THCa yields 0.877 grams of THC
Where the full report lives
The Certificate of Analysis (COA), tied to the package tag and batch number
THCa vs THC: The Short Answer
Cannabis plants make THCa, not THC. The acid form builds up in the trichomes and stays mostly intact through drying and curing. Heat changes it: a reaction called decarboxylation knocks a carboxyl group off the molecule and leaves THC behind. A lighter, a vaporizer, or a processor's oven all do the job.
That is why "Total THC" exists as a label term. The lab measures the THCa that hasn't converted and the delta-9 THC that already has, runs them through one formula, and reports how much THC the product can deliver once it's heated.
The Total THC Formula
The math fits on one line: Total THC = (THCa × 0.877) + delta-9 THC. The 0.877 is a molecular weight ratio: the carboxyl group THCa sheds is about 12 percent of its mass, so a gram of THCa can only become 0.877 grams of THC. Labs measure both compounds as they are and apply the factor.
Here's how a jar labeled 30.6%, like Common Citizen's Monkey Bread ($19 an eighth as of Oct 2026), could get there. Picture a COA that reads THCa 33.9% and delta-9 THC 0.9%. Multiply 33.9 by 0.877, and you get 29.7; add the 0.9, and you land at 30.6%. The THCa line reads higher than the label because of the conversion loss, and both numbers describe the same jar.
On a vape pod, the split runs the other way. STIIIZY's Live Resin Liquid Diamonds pods test at 84.35% (1g, $20.72 as of Oct 2026), and much of that conversion happened during processing, so the delta-9 line carries more of the weight.
Anatomy of a Michigan Cannabis Label
Michigan's packaging rule (R 420.504) lists what has to be on a product before a licensed store can sell it. Brands lay it out differently, but the pieces are the same.
Product name, strain, and net weight
The product name, the strain where it applies, and the net weight in grams or ounces.
THC and CBD content
The lab-reported figures, as percentages for flower, concentrates, and vapes or milligrams for edibles, plus a required note that the actual value may vary by up to 10 percent.
Producer, license number, and package tag
The grower or processor's name and license number, plus the METRC package tag and batch number that connect the product to its lab results.
Dates and activation time
The harvest date where it applies, and an activation time, in words or a pictogram, for how long the format takes to kick in.
Lab name and the universal symbol
The lab that ran the passing compliance test, often with the test date, plus Michigan's universal symbol for cannabis products.
What the Warning Label Means
Every package carries a block of state-required warnings. Here they are in plain words.
Driving
It is illegal to drive while under the influence of cannabis in Michigan.
Poison control
The National Poison Control Center number, 1-800-222-1222, is on the package. Call it if a kid or a pet gets into something.
Age and storage
Adult-use products are for people 21 and older (or registered patients) and belong out of reach of children, which is why the packaging is child-resistant.
Pregnancy
A boxed statement, set off by a heavy line, about use during pregnancy or breastfeeding, written by the state and printed word for word on every package.
What a COA Shows, and Where to Find One
The Certificate of Analysis is the full lab report behind the label. Every product on a licensed Michigan shelf went through a CRA-licensed safety compliance lab first, and the COA is the record that it passed.
It opens with the cannabinoid panel (THCa, delta-9 THC, CBD, CBDa, often CBG and CBN) and the Total THC calculation. Then come the safety screens, each marked pass or fail: foreign matter, microbials, heavy metals, chemical residue (the pesticide screen), residual solvents on solvent-based extracts, water activity, and vitamin E acetate plus MCT on vape cartridges. Terpene testing is optional under state rules, so it appears on some COAs and not others.
Many brands print a QR code on the package that opens the COA for that batch, and others post lab results on their own site, searchable by the batch number on your label. If you can't find one, ask a budtender and we'll point you to where that brand publishes it.
Terpene Percentages on the Label
Terpenes are the aromatic compounds behind a strain's smell and flavor: the lemon peel in a Lemon Cherry Gelato, the fuel in a Garlic Breath. When a brand prints them, you'll see a total terpene percentage plus the top two or three by weight, with names like limonene, caryophyllene, myrcene, and linalool.
The number looks small next to THC, and that is normal. Terpene totals for flower land in the low single digits, so 30% THC next to 2% terpenes isn't a typo. Between two jars, the one with the higher terpene total usually smells and tastes louder, which tells you more than a two-point THC difference does.
Our Lemon Cherry Gelato guide walks through its caryophyllene, limonene, and linalool stack, and the strain library does the same for the rest.
Is a Higher THC Percentage Better?
Higher means more THC by weight, and that is all it means. The number says nothing about flavor, how the flower was grown and handled after harvest, how an extract was made, or whether you'll like it.
Format matters more than the number, too. Flower in the 20s and 30s, infused pre-rolls in the 30s and 40s, and concentrates and vapes in the 70s and 80s are all normal for what they are, so compare within a category rather than across one. If you're new, a lower number with room to go slow is a fine place to start.
"THCa Flower" Sold Online vs. What a Michigan Dispensary Sells
The "THCa flower" sold online and in smoke shops comes out of a different rulebook. Federal law has defined hemp by delta-9 THC content, 0.3 percent or less by dry weight, so flower that is high in THCa but low in already-converted delta-9 can be sold as hemp outside the licensed system. It's a separate market with its own testing, labeling, and oversight, and that definition is changing: a 2025 federal amendment redefines hemp by total THC with THCa included.
Everything at Banzen is Michigan adult-use cannabis: grown and processed by state licensees, tested by a CRA-licensed lab, and labeled under the rules above. The Total THC on our shelf already includes the THCa conversion.
THC Percentages on the Shelf at Banzen
Every card on our Blaze menu shows the lab-reported Total THC, sorted highest first by default. Here are the ranges, with prices as of Oct 2026.
Flower, roughly 24–36%
Infused pre-rolls, roughly 26–47%
Live resin and rosin, roughly 64–81%
Edibles, in milligrams
Sort the live menu by THC to see every number above on a product card.
Where to Buy Lab-Tested Cannabis in Coldwater, MI
BANZEN Dispensary
55 S. Michigan Ave
Coldwater, MI 49036
Sunday – Saturday: 9am – 9pm
Happy Hour: 4pm – 4:30pm
Every product at Banzen comes with the label and lab report described above, from Common Citizen deli flower to STIIIZY pods, and our crew is happy to talk through any number on it you don't recognize. Start on our flower page, sort the live menu by THC and order ahead, or browse more guides in the Learn hub.
THCa vs THC FAQ
THCa (tetrahydrocannabinolic acid) is the cannabinoid the cannabis plant produces before any heat is applied, and the main compound in raw flower. Heat converts it to THC through decarboxylation.
No. THCa is the acid form and THC is what it becomes after heating; they're different molecules with different weights, which is where the 0.877 in the Total THC formula comes from.
Total THC is the lab's estimate of how much THC a product can deliver once it's heated: THCa × 0.877 plus the delta-9 THC that already converted. It's the number on the package and the one our menu sorts by.
Higher means more THC by weight and nothing else. Flavor, terpenes, and how the product was made matter as much, and normal ranges differ by format, so compare within a category.
A Certificate of Analysis is the full lab report for a batch: the cannabinoid panel with Total THC shown, plus pass or fail results for each safety screen. Every product on a licensed Michigan shelf has one.
Check the package first: many brands print a QR code that opens the COA, and others post results on their site under the batch number from your label. If you can't find it, ask a budtender and we'll point you to where that brand publishes its lab results.
THCa is the unconverted acid form, and delta-9 THC is the small share that already converted during drying and curing. The Total THC line combines them using the 0.877 factor.
Edibles are labeled by milligrams of THC per serving and per package, since a percentage of a gummy's weight wouldn't tell you much. Michigan caps adult-use edibles at 10mg per serving and 200mg per package; our guide to how long edibles take to kick in covers the timing side.
Sources
- Michigan Administrative Code R 420.504, Marihuana product sale or transfer; labeling and packaging requirements (required label contents, the 10 percent variance statement, and the exact warning text)
- Michigan Cannabis Regulatory Agency, Sampling and Testing Technical Guidance for Marijuana Products, v5.2 (Sept 23, 2024): required safety tests by product type, potency reported without moisture correction, vitamin E acetate and MCT on vape cartridges, terpene testing not required
- Michigan CRA, Scientific Section (oversight of safety compliance facilities)
- 7 CFR 990.1, USDA hemp program definitions (decarboxylation; Total THC = (0.877 × THCA) + THC)
- 7 U.S.C. 1639o, federal definition of hemp (delta-9 THC not more than 0.3 percent on a dry weight basis; 2025 amendment, Pub. L. 119-37, moves the definition to total THC including THCa, effective 365 days after enactment)
- Metrc Michigan Bulletin 47, COA upload and functionality (labs attach COAs to packages in Metrc; licensees with permissions can view and download them)