Cannabinoids: definition, 3 families and what is legal

A cannabinoid can be defined in two ways that overlap. Chemically, the word covers the molecules specific to hemp that share the skeleton of THC and CBD. Pharmacologically, it covers any molecule that binds to the cannabinoid receptors, whether it comes from the plant, the body or a lab.

The discoveries came in that order. Raphael Mechoulam described the structure of CBD in 1963 and that of THC in 1964. The CB1 receptor was cloned in 1990, when a study published in Nature described a G protein-coupled receptor present in the brain. CB2, found mainly in immune cells, followed in 1993. If these receptors existed, the body had to make molecules to activate them, and those were identified in 1992 and 1995. Together they make up the endocannabinoid system.

A review published in 2021 in Molecules counts more than 500 compounds in Cannabis sativa and identifies 125 of them as cannabinoids. Its authors sort them into 11 chemical types, among them the CBD, Δ⁹-THC, CBG, CBC and CBN types. The plant makes them in its trichomes, the small resin glands on female flowers.

The main ones all start from a single molecule, cannabigerolic acid (CBGA), which the plant produces first. Then three enzymes, THCA synthase, CBDA synthase and CBCA synthase, convert it into THCA, CBDA and CBCA. Which of them dominates depends on the cultivar's genetics, and CBD hemp mostly carries CBDA synthase. Heat or light then strips a carboxyl group from these acidic forms, which become CBD, THC, CBC or CBG. The process is called decarboxylation.

CBN takes another route, since the plant does not produce it. It forms as THC breaks down with time and oxidation, and it binds to the CB1 and CB2 receptors less well than THC does.

Rarer phytocannabinoids such as THCV or CBDV are also under study. Only the lot analysis shows whether a product contains them; the label alone never does.

Yes. Δ⁹-THC is a phytocannabinoid that binds to the CB1 receptor as a partial agonist, and that binding accounts for its psychoactive effect. Being a cannabinoid does not make a molecule psychoactive, though: CBD, CBG and CBC belong to the same chemical family without producing that effect.

French law also separates them. Article R5132-86 of the French Public Health Code bans "tetrahydrocannabinols, natural or synthetic" and does not name CBD. Our article on Δ⁹-THC in France sets out its status.

The human body makes cannabinoids of its own. The first, anandamide, was isolated in 1992 from pig brain by researchers looking for molecules able to bind to the cannabinoid receptor. Its name comes from the Sanskrit ananda, "bliss". The second, 2-arachidonoylglycerol or 2-AG, was described in 1995 by two teams, one in Israel and one in Japan.

Neither molecule has the structure of CBD or THC. Both derive from arachidonic acid, a fatty acid; the body makes them on demand, and enzymes then break them down. THC partly mimics what they do at the CB1 receptor, hence its psychoactive effect. CBD binds only weakly to CB1 and CB2 and has many studied targets, detailed in the endocannabinoid system article linked above.

Synthetic cannabinoids are made in laboratories to activate the CB1 receptor, and their intensity is what sets them apart from THC. A review published in 2025 notes that THC is a partial CB1 agonist, while most synthetic cannabinoids on the market are full agonists, some more than 100 times as potent. The best-known example is JWH-018, found in "Spice" or "K2" blends.

Semi-synthetic molecules, made by chemically modifying a hemp cannabinoid, have also spread on the CBD market. ANSM classed HHC, HHCO and HHCP as narcotics from 13 June 2023, then H4CBD, THCP and other derivatives from 3 June 2024. The same decision also covers THCA, except when it is present in hemp whose THC content meets the 0.30% limit.

These products are still sold under misleading names. Our article on synthetic cannabinoids explains how to recognise them, and the HHC timeline retraces its ban.

Everything hinges on one threshold. The order of 30 December 2021 authorises the Cannabis sativa L. varieties listed in the official catalogues whose Δ⁹-THC content does not exceed 0.30%, and extends that ceiling to extracts and to the products containing them. The Conseil d'État struck down on 29 December 2022 the order's ban on selling raw flowers and leaves.

Two more limits apply. MILDECA, the French interministerial drugs agency, notes that CBD products may not make therapeutic claims, on pain of criminal penalties, unless they are authorised as medicines. A cannabinoid meant to be swallowed also comes under the novel food rules, set out in our overview of CBD regulation in 2026.

Epidyolex, a solution of purified CBD, is the only CBD medicine available in France. It has been authorised in the European Union since 2019, on the opinion of the European Medicines Agency. The authorisation covers add-on use with other medicines in Lennox-Gastaut syndrome and Dravet syndrome, together with clobazam, and in tuberous sclerosis complex, from the age of 2. Only neurologists and paediatric neurologists may prescribe it. The trials behind this authorisation are summed up in our article on Epidyolex.

Medical cannabis contains THC and takes a different route. The French experiment ended on 31 December 2024. According to ANSM, the transition period that followed will end three months after the French National Authority for Health (HAS) publishes its opinion. Our update on medical cannabis in 2026 follows the file.