THC, strictly Δ9-tetrahydrocannabinol, is the neutral cannabinoid that acts on CB1 receptors and is associated with the reported intoxicating effects of cannabis. The plant makes very little of it directly. It makes THCA, which loses a carboxyl group (decarboxylation) with heat and time to become THC. With further oxidation, THC slowly degrades to CBN.
In practice
On a COA for dried flower, Δ9-THC itself is usually a small number, often under 1-2% w/w, while THCA might read 18-25%. The figure on a retail label is normally "total THC", which combines both. When someone says "this plant is 22% THC", they nearly always mean total THC, not the Δ9-THC line.
Units and formula
Reported as % w/w (or mg/g; 1% = 10 mg/g). Total THC = Δ9-THC + 0.877 × THCA.
Don't confuse with
- THCA: the acid form the plant actually makes; not intoxicating until decarboxylated.
- Delta-8 THC: an isomer present only in traces in the plant; commercial delta-8 is converted from CBD.
- Total THC: a calculated figure, not a single measured compound.
A cannabinoid is any compound that binds the body's cannabinoid receptors or shares the typical cannabis terpenophenolic structure; the plant-made ones are phytocannabinoids such as THCA and CBDA.THCA (tetrahydrocannabinolic acid) is the acid cannabinoid that drug-type cannabis makes in its trichomes; heat or time decarboxylates it into THC, losing about 12% of its mass.Decarboxylation is the loss of a carboxyl group as CO2 that turns acid cannabinoids such as THCA and CBDA into neutral THC and CBD, quickly with heat, slowly with time.CBN (cannabinol) is a cannabinoid formed mainly when THC or THCA oxidises after harvest, so high CBN readings usually signal age, heat, light or air exposure, not plant ripeness.A COA (certificate of analysis) is a lab's signed report of what it measured in a specific sample, such as cannabinoids, terpenes, moisture and contaminants, with methods and limits.Total THC is a calculated figure, Δ9-THC plus 0.877 × THCA, estimating the maximum THC a sample could yield after full decarboxylation.Delta-8 THC is an isomer of THC with the double bond shifted one position; the plant makes only traces, so commercial delta-8 is semi-synthetic, usually converted from CBD.CBD (cannabidiol) is a non-intoxicating neutral cannabinoid formed when CBDA decarboxylates; hemp-type and CBD-dominant cannabis make it mainly as CBDA in their trichomes.
