How does CBD oil work? Mechanisms and limits

Identified from 1988 onwards, the endocannabinoid system (ECS) is a cellular communication network present throughout the human body. According to Inserm's dossier, it is involved in regulating functions as varied as appetite, sleep, pain, memory, mood, thermoregulation and immune function.

The ECS rests on three elements. First, receptors: CB1, found predominantly in the central nervous system, and CB2, located mainly in immune cells and peripheral organs. Next, endocannabinoids produced by the body: anandamide (AEA) and 2-arachidonoylglycerol (2-AG). Finally, enzymes that synthesise and break down these molecules, notably FAAH (fatty acid amide hydrolase) and MAGL.

This is where the fundamental difference between CBD and THC plays out.

• THC binds directly, and with strong affinity, to the CB1 receptors of the brain. That binding produces the psychoactive effect characteristic of cannabis: altered perception, euphoria, impaired short-term memory.
• CBD, by contrast, has a very weak affinity for CB1 and CB2. It therefore does not activate the receptors directly. Its action is described as "modulatory": it partially inhibits FAAH (the enzyme that breaks down anandamide), which lets that endogenous endocannabinoid circulate in the body for longer. It also acts on other targets: 5-HT1A serotonergic receptors, TRPV1 receptors, PPAR receptors, GPR55.

It is this plurality of biological targets that explains why research on CBD covers so many fields (anxiety, sleep, pain, inflammation), but also why it is difficult to attribute a precise and reproducible effect to the molecule.

The cannabidiol placed on the market is extracted from hemp varieties listed in the common European catalogue or the official French catalogue, whose THC content in the plant is below 0.30%. The most widespread extraction methods are supercritical CO2 (preserving heat-sensitive compounds, leaving no solvent residue) and ethanol extraction (good yield, a different aromatic profile).

The resulting extract is then diluted in a carrier oil (MCT oil from coconut, hemp oil, olive oil). The final concentration is expressed in mg of CBD per bottle or as a percentage. Compliance with the 0.30% THC threshold in the finished product, set by the Conseil d'État ruling of 29 December 2022, determines whether the product is lawful.

The form of the product influences the kinetics of absorption.

• Sublingual route (oil under the tongue, held for 60 to 90 seconds): absorption through the oral mucosa, with an effect felt within 15 to 45 minutes where there is any sensation at all.
• Oral route (capsules, gummies, infusions): passage through the digestive system, a later effect (60 to 120 minutes), a longer duration but lower bioavailability (hepatic first-pass effect).
• Topical route (cosmetics, balms): local action on the skin and surface tissues, with no significant systemic passage.
• Pulmonary route (vaping): a rapid effect (a few minutes), a shorter duration.

The mechanism of action set out above, well documented in experimental pharmacology, does not automatically translate into established clinical effects in humans. No French authority (ANSM, HAS, ANSES) has validated a health claim for wellbeing CBD. The EFSA has authorised no claim at European level.

ANSES, in its 2024-2025 opinion, has even raised toxicological concerns, notably about reproductive risk (a proposed CLP classification in category 1B, "presumed toxic for reproduction"). On 9 February 2026 the EFSA published a very low provisionally safe daily dose (0.0275 mg/kg/day, that is roughly 2 mg/day for a 70 kg adult).

In practical terms, a French seller cannot assert that CBD "relieves", "treats", "cures" or "reduces" anything at all. The permitted vocabulary is that of wellbeing: "a relaxation ritual", "a moment of pause", "a relaxation practice", "a complement to a routine".

CBD oil remains inadvisable for women who are pregnant, breastfeeding or of childbearing age, for minors and for people undergoing medical treatment. Several drug interactions have been documented, notably with anticoagulants, antiepileptics and certain immunosuppressants. Medical advice is recommended where the two are taken together.

CBD is not a medicine. In the event of medical symptoms, consult a healthcare professional.

• CBD acts on the endocannabinoid system but does not bind directly to the CB1 and CB2 receptors.
• Its action is indirect: enzymatic modulation (FAAH) and interactions with serotonergic, TRPV1 and PPAR receptors.
• Unlike THC, CBD is not psychoactive.
• No therapeutic claim is authorised in France or in Europe for wellbeing CBD.
• Wellbeing use only, inadvisable for pregnant or breastfeeding women, minors and people undergoing treatment.

• Conseil d'État, 29 Dec. 2022, No. 444887 (flowers/leaves) — primary
• EFSA Journal 2026 — Update statement CBD novel food — primary
• ANSES — Press release of 19 June 2025 on the reprotoxic CBD classification (PDF) — primary