CBDA (cannabidiolic acid): the raw form of CBD
CBDA, or cannabidiolic acid, is the form in which hemp makes CBD. Heat strips its extra carboxyl group, a reaction called decarboxylation that turns CBDA into CBD. At 110 °C, half of the CBDA in an extract is converted in about 14 minutes; at room temperature, the same reaction takes months.
Key takeaways
- CBD comes directly from CBDA, which the plant makes from CBGA with an enzyme, CBDA synthase.
- Temperature drives the conversion to CBD: the half-life falls from 231 minutes at 80 °C to 14 minutes at 110 °C.
- A certificate of analysis gives total CBD as CBD + 0.877 × CBDA.
- Research on CBDA is mostly preclinical, and no medicine contains it.
- In France, a food containing CBDA is not allowed, any more than a CBD food.
What is CBDA?
CBDA is an acidic cannabinoid. Hemp (Cannabis sativa L.) does not make CBD, THC or CBC directly; it first produces their acidic forms, all starting from cannabigerolic acid, CBGA. A 2021 review in Frontiers in Pharmacology describes three enzymes that compete for this CBGA and turn it into THCA, CBDA or CBCA. CBDA synthase dominates in a CBD-rich variety.
CBDA is the native form of CBD, in the living plant and in a flower that has only been dried; it is no by-product. Our page on CBG, the mother molecule, describes the step before.
| Acidic form (in the plant) | Neutral form (after heating) | Psychoactive effect of the neutral form |
|---|---|---|
| CBGA | CBG | No |
| CBDA | CBD | No |
| THCA | THC | Yes |
| CBCA | CBC | No |
A single chemical group, the carboxyl (COOH), separates CBDA from CBD. CBDA weighs 358.5 g/mol and CBD 314.5 g/mol, so the molecule loses about 12% of its mass when this group leaves as CO₂.
From CBDA to CBD: decarboxylation, with numbers
Decarboxylation, the reaction that removes the carboxyl group, is the name of the process that converts CBDA into CBD. Heat is what mainly drives it.
A 2016 study in Cannabis and Cannabinoid Research heated flower extracts in a vacuum oven at 80 to 145 °C, for up to 60 minutes, and measured a reaction rate at each temperature. For CBDA, the rate constant climbs from 0.05 × 10⁻³ per second at 80 °C to 0.83 × 10⁻³ per second at 110 °C, about half the rate of THCA. From these constants we derived half-lives, the time needed to convert half of the CBDA.
Three practical lessons follow. As the authors note, the reaction is incomplete after an hour below 100 °C. Above that, it speeds up quickly. And the CBDA reaction comes with losses: in the extracts, the sum of CBDA + CBD fell by 18% at 110 °C and by 25% at 130 °C, as some molecules broke down or became something other than CBD. Longer heating does not automatically yield more CBD.
The conversion also happens at room temperature, slowly. A January 2026 review in the Journal of Cannabis Research states that acidic cannabinoids decarboxylate slowly during prolonged storage, with heat still the dominant factor; light and air also contribute. Our guide to decarboxylation covers home methods.
Reading CBDA on a certificate of analysis
A dried CBD flower contains mostly CBDA and little CBD. Liquid chromatography (HPLC) does not heat the sample, so a certificate produced this way lists the two on separate lines. Adding them overstates the total, because CBDA loses 12% of its mass on becoming CBD.
The standard calculation is total CBD = CBD + 0.877 × CBDA. Take a hypothetical flower showing 1.2% CBD and 9.0% CBDA: its total CBD is 1.2 + 0.877 × 9.0, or 9.1%. This figure is the one that matters once the flower is heated, in a vaporiser for example.
THCA follows the same reasoning, with the same 0.877 factor, and it is THCA that counts for the legal THC limit, as our page on THCA explains. Our guide to reading a certificate of analysis takes each line in turn, and the laboratory page presents the measurement methods.
What research says about CBDA
Nearly all the data on CBDA come from cells and animals. The 2021 review cited above describes CBDA as a modulator of the serotonin 5-HT1A receptor: in vitro, it strengthens the binding of an agonist of this receptor. In rodents, low doses of CBDA reduced nausea-related behaviours, with a potency about 1,000 times that of CBD in these models. The same review reports in vitro inhibition of the COX-2 enzyme, nine times more selective than for COX-1.
In humans, the 2026 review notes the lack of well-controlled clinical trials. It cites one published trial, phase I/II and open-label with no placebo group, which gave a CBDA-rich extract to patients with Rett syndrome. Such a trial allows no conclusion about any effect. No authorised medicine contains CBDA; the only cannabidiol medicine, Epidyolex, contains purified CBD.
Legal status of CBDA in France
CBDA is not classified as a narcotic. The ANSM decision in force from 3 June 2024 covers H4CBD, THCP and HHCPO, and excludes THCA present in hemp that meets the THC limit. CBDA therefore follows the hemp framework, in which the order of 30 December 2021 caps Δ⁹-THC at 0.30% in varieties, extracts and the products containing them.
Products you swallow are another matter. Regulation (EU) 2015/2283 requires authorisation for any food rarely consumed in the Union before 15 May 1997. On 20 May 2026, the French Ministry of Agriculture restated that foods containing CBD or any other cannabinoid are not authorised and must be withdrawn from the market. That rule catches raw hemp juice or a "raw" tincture sold as food. Our overview of CBD regulation in 2026 describes what is still on sale, and our page CBD: definition and French framework puts CBD in context.
Frequently asked questions
CBDA is the acidic form the plant produces, and CBD the neutral form left once heat removes the carboxyl group from CBDA. Neither makes you "high".
Decarboxylation. At the rates measured in the 2016 study, half of the CBDA in an extract is converted in about 43 minutes at 95 °C and in 14 minutes at 110 °C.
The flower has not been heated, and CBD only appears after decarboxylation. To estimate the CBD potential, calculate CBD + 0.877 × CBDA.
In a flower, resin or cosmetic made from authorised hemp with no more than 0.30% Δ⁹-THC, yes. In a food or food supplement, no: these fall under the novel food regime and have received no authorisation.
Nothing supports that claim. The potency comparisons come from animal models, and the only published human trial had no placebo group.
Written by the Phytogrammes team
Each journal article draws on cited primary sources: ANSM, EFSA, EUR-Lex and peer-reviewed publications. Product profiles are distinguished from documented laboratory results. Our approach.
Article published on . CBD is not a medicine.