Study type: Biochemistry2016
Instrument · decarboxylation and ageing
Heat, time and light.
The plant stores its cannabinoids as acids. Heat strips the carboxyl group off as CO₂ and leaves the neutral compound; air, light and time then push the THC line on toward CBN. One registry study gives the decarboxylation its shape: first-order, faster with temperature, THCA about twice as fast as CBGA or CBDA. Set the dials and turn the shape over. The speeds are drawn, not measured, and the page says so wherever a number appears.
Evidence library·21 studies·updated 9 August 2026·How we check
The instrument
Three reactions, one shape.
THCA → THC and CBGA → CBG are the same reaction on different molecules, and the registry says the first runs about twice as fast. THC → CBN is a different process altogether, driven by oxygen and light, and our registry holds no kinetics for it, so the instrument reports it in words. The curves follow the dials at the top of the page; the one registry study behind them is the card beneath.
At 110 °C: fraction converted against minutes
- THCA → THC
- CBGA → CBG and CBDA → CBD (half the rate)
On the shelf at room temperature: the slow creep, in months
- THCA → THC on the shelf
- CBGA → CBG on the shelf
What the registry holds. Wang 2016 measured decarboxylation of the acidic cannabinoids as approximately first-order over 80–145 °C, with THCA-A about twice as fast as CBDA or CBGA (PMID 28861498). It supplies the shape of these curves and the ratio between them. No rate constant at any temperature, and no CBN kinetics, are in our registry, so the speed you see here is a drawing choice.
What the shape teaches
Three consequences of one reaction.
Each lesson is settled chemistry already stated on the compound pages; the chip carries the grade those pages give it. None of them is a claim about what any compound does in the body.
Lesson 1 · the lawgrade: Established
Why “THCA flower” is legally contested
Watch the THCA curve climb and you are watching the whole argument. Under a Δ9-only reading of the hemp definition, flower is judged by the Δ9-THC in the jar, and raw THCA-rich flower can sit at or below the line. Under a total-THC reading, it is judged by what heat will make of it: total THC = Δ9-THC + 0.877 × THCA. The 0.877 is chemistry, the molar-mass ratio of THC to THCA, or the share of THCA's mass left once CO₂ has gone. Jurisdictions split on which reading applies, and the same jar can pass one and fail the other.
As of 2026; general information, not legal advice. Verify locally. The legal split, on the THCA page →
Lesson 2 · the shelfgrade: Established
Why old product moves on a drug test
Set the temperature to room and the minutes to zero, then slide the months. The curve still rises. Decarboxylation does not switch off below oven heat; it creeps, so a raw product drifts toward THC while it sits, faster with warmth and light. A certificate of analysis describes the product on its test date and on that date alone, and standard workplace screens look for THC metabolites. Anyone subject to testing is safest avoiding THCA products altogether.
Lesson 3 · ageinggrade: Established
Why aged stock carries CBN
Turn on light and air and leave the months up. The plant makes no CBN on purpose: there is no CBN synthase. It forms as Δ9-THC and THCA oxidise with exposure to air, light and time, which is why fresh material carries mere traces while aged, oxidised or poorly stored material builds up more. On a certificate of analysis, THCA falling while CBN climbs is the signature of an older product.
Where this sits
The acids, and what they become.
The reactions drawn here run across the whole family. The acids have their hub at cannabinoid acids; the mother acid is CBGA; the acid the market argues over is THCA; the product of age is CBN. To see the carboxyl group heat removes, drawn atom by atom, open molecule pairs. For how a claim earns its grade, see how we grade. Peregrine Biopharma funds the platform and holds no editorial authority.
Informational only
Informational only; not dosing, testing or legal advice. The instrument draws the shape of a reaction and recommends no temperature, time or process. Nothing here describes an effect of any compound. Report a safety event.