What is THCA? THCA vs THC and its legal status in France
By the Golden High teamUpdated 15 October 20268 min read
Cannabinoids
If you're wondering what is THCA, here's the short answer: THCA, or tetrahydrocannabinolic acid, is the form THC takes in the living plant, an acidic precursor that isn't psychoactive as it is, but that turns into THC as soon as it's heated, for example when you smoke it. That's why the ANSM (the French medicines agency) classed it as a controlled drug on 3 June 2024, and why "THCA flower" is not a legal product in France. Here's how it works, what sets it apart from THC, and where the confusion comes from.
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What is THCA? THC before the heat.
A fresh cannabis flower contains almost no "ready-to-use" THC. The plant mainly makes its acidic form, THCA (more precisely THCA-A), in its glandular trichomes, the tiny resin glands that cover the flowers and leaves. According to a review published in 2016 in Cannabis and Cannabinoid Research, THCA can account for up to 90% of the total THC in the plant.
The difference from THC comes down to a small group of atoms, the carboxyl group. As long as it's there, the molecule doesn't have THC's psychoactive effects: the same review points out that, unlike THC, THCA doesn't produce psychoactive effects in humans. But that group is fragile. A little heat is all it takes to knock it off.
- Full name: delta-9-tetrahydrocannabinolic acid (THCA-A).
- Origin: natural, made by the plant in its trichomes.
- Effect as it is: not psychoactive in humans.
- Once heated: becomes THC, which is psychoactive.
- Status in France: controlled drug since 3 June 2024.
THCA vs THC
THCA vs THC: it's all about heat.
The switch from THCA to THC is called decarboxylation. Heat strips off the carboxyl group as carbon dioxide, and what's left is THC. According to the 2016 review, this happens slowly during storage and drying, and very quickly when you smoke, vape or cook. Over time, THC can then break down into CBN.
Researchers at the University of Mississippi measured this reaction in the lab between 80 and 145 °C: for THCA, it follows steady kinetics with no side reactions or by-products, roughly twice as fast as for CBDA or CBGA. In other words, heating THCA means producing THC, predictably.
| THCA | THC (delta-9) | |
|---|---|---|
| Form | Acidic, found in the fresh plant | Neutral, obtained after heating |
| Psychoactive effect | No, as it is | Yes |
| When smoked | Turns into THC | Acts directly |
| Status in France | Controlled drug since 3/06/2024 | Controlled drug (hemp tolerated under 0.3%) |
To get a clear picture of THC itself, read our article what is delta-9, and to compare all these molecules at a glance, see our HHC, THC, THCP and Delta-P comparison.
What the sources say
What the studies and the law say.
THCA has barely been studied in humans, but its chemistry is well understood. Here are the most solid references.
Cannabis and Cannabinoid Research · 2016 (review)
THCA-A is the acidic precursor of THC. It builds up in the trichomes, can account for up to 90% of total THC, and decarboxylates slowly in storage and quickly when smoked, vaped or cooked. Unlike THC, it doesn't produce psychoactive effects in humans.
Cannabis and Cannabinoid Research · 2016 (study)
The decarboxylation of THCA-A, measured between 80 and 145 °C, follows a first-order reaction, with no side reactions or by-products.
US federal regulations · 7 CFR 990.1
"Total THC" is calculated there as the sum of delta-9-THC and 87.7% of THCA, which matches the mass lost during decarboxylation.
ANSM · June 2024
THCA is among the cannabinoids added to France's list of controlled drugs from 3 June 2024. An amendment excludes THCA naturally present in hemp, where the THC content stays within the 0.3% threshold.
Full references at the bottom of the page.
The maths
Total THC: what the label hides.
Because THCA turns into THC when burned, authorities that want to measure what will actually be consumed add the two together. The formula used in US regulations is simple: total THC = THC + 0.877 × THCA. The 0.877 coefficient is the share of the molecule left once the carboxyl group is gone.
That's the whole idea behind "THCA flower": show a very low THC figure on the lab report, while the product behaves like regular cannabis as soon as you light it.
Is THCA legal?
THCA in France: a controlled drug since June 2024.
In a decision of 22 May 2024, amended on 3 June 2024, the ANSM added cannabinoids with a benzo[c]chromene core to France's list of controlled drugs, including THCA, alongside THCP, HHC and its derivatives, H4-CBD and H2-CBD. The amendment specifies that traces naturally present in hemp products remain excluded, provided the THC content stays within the 0.3% threshold.
30 Dec. 2021
A French decree sets the maximum THC content of authorised hemp varieties at 0.30%.
22 May 2024
ANSM decision adding new cannabinoids, including THCA, to the list of controlled drugs.
3 June 2024
Entry into force, with natural traces in compliant hemp excluded.
Key takeaway: a flower, resin or vape sold as "THCA" or "THCA-rich" is not a legal hemp product in France. Only natural traces of THCA in hemp that meets the 0.3% THC threshold escape the classification.
For the full picture of what is and isn't allowed, read our guide legal weed in France: what's allowed in 2026.
Where the trend comes from
"THCA flower": a product from the US.
If you've seen "THCA flower" online, it mostly comes from the American market. There, the 2018 farm law (Farm Bill) defined hemp by its delta-9-THC content alone. Some sellers took advantage of that to market flowers very rich in THCA but low in THC before heating.
Congress changed the rule in late 2025: the new federal definition of hemp uses a total THC concentration, THCA included, of 0.3% at most, and caps finished products at 0.4 mg of total THC per container. According to law firm DLA Piper, these provisions take effect on 12 November 2026. In France, the question has been settled since June 2024.
- Trusting the listed THC figure alone without checking the THCA line on the lab report.
- Assuming a "legal" US product is legal in France too: it's not the same law.
- Ordering "THCA flower" online: in France, it's a controlled drug.
What about us?
Our flowers: strength displayed, THC under 0.3%.
Golden High only sells products under 0.3% THC, lab-tested, and doesn't sell "THCA flower". Our Delta-P range is based on CBDX: it's not THCA, not THC and not HHC. You'll find the details on the molecule on our dedicated Delta-P page.
To ease in gently, Gelato Delta-P 10 % and Amnesia Delta-P 12 % are among our most moderate strengths. You'll find the whole range in our Delta-P flowers. And as with any smokable product: start low, leave time between doses, and never before driving.
Your questions
What people ask us about THCA.
What is THCA?
It's tetrahydrocannabinolic acid, the acidic form of THC made by the plant. It isn't psychoactive as it is, but it turns into THC when heated.
Is THCA legal in France?
No. In France, THCA has been classed as a controlled drug since 3 June 2024 by an ANSM decision. Only its natural traces in hemp whose THC content stays within the 0.3% threshold are excluded.
THCA vs THC: what's the difference?
THCA carries an extra carboxyl group. As long as it's there, the molecule isn't psychoactive. Heat removes it, and THCA then becomes THC.
Does THCA get you high?
Not as it is. But smoked or vaped, it quickly turns into THC, which is psychoactive. That's why a THCA-rich flower behaves like regular cannabis.
How is total THC calculated?
US regulations use the formula total THC = THC + 0.877 × THCA. The coefficient matches the mass lost during decarboxylation.
Why is THCA flower on sale?
It mostly comes from the American market, where hemp was long defined by its delta-9-THC content alone. In France, these are controlled drugs.
Do saliva tests detect THCA?
Once smoked, THCA has become THC, which is exactly what drug tests look for. And in France, the offence of driving after using drugs has no tolerance threshold.
Sources
The references cited in this article.
- Moreno-Sanz G., Cannabis and Cannabinoid Research (2016). Can You Pass the Acid Test? Critical Review and Novel Therapeutic Perspectives of Δ9-Tetrahydrocannabinolic Acid A.
- Wang M. et al., Cannabis and Cannabinoid Research (2016). Decarboxylation Study of Acidic Cannabinoids: A Novel Approach Using Ultra-High-Performance Supercritical Fluid Chromatography/Photodiode Array-Mass Spectrometry.
- ANSM (2024). The ANSM adds new cannabinoids to the list of controlled drugs (in French).
- Légifrance. Decree of 30 December 2021 applying Article R. 5132-86 of the Public Health Code (in French).
- eCFR. 7 CFR 990.1 — Meaning of terms (Domestic Hemp Production Program).
- DLA Piper (2025). New federal restrictions on hemp and hemp-derived products: Top points.
- French Court of Cassation, Criminal Chamber, 21 June 2023. Appeal no. 22-85.530 (in French).
