Topic collection

Cannabinoids.

A plain-language introduction to cannabinoids, the body’s endocannabinoid signalling system, and why product labels do not answer every evidence question.

Readability reviewed 6 Nov 2026

What do these dates mean?

Prepared is when this page was drafted. A readability review checks clarity. Dates alongside individual sources record when those sources were accessed or checked. Read our editorial standards →

The answer so far

Cannabinoids are a broad group of compounds, not one treatment. Cannabis plants, purified compounds, prescription medicines and shop-bought products can differ in ingredients, quality, exposure, evidence and legal status.12

Compound ≠ product

Start with the molecule and product

Cannabis contains multiple cannabinoids. Delta-9-THC is the main intoxicating cannabinoid in ordinary cannabis. Cannabidiol, or CBD, does not cause THC’s typical intoxication, but it is not risk-free. A purified compound, plant extract and retail product are not interchangeable. Their form, how they are taken, concentration, contaminants and stability can all matter.314

Illustrations

Cannabinoids and the endocannabinoid systemSupplied illustration in English

CBD does not simply act by binding CB1 or CB2; see the article for the limits of this simplified diagram.

Cannabinoids and the endocannabinoid systemOpen image at full size

The body has its own cannabinoid signalling

The body makes its own signalling molecules, including anandamide. Together with receptors, they form part of the endocannabinoid system that helps cells communicate. THC can activate cannabinoid receptors in the brain, affecting memory, coordination and perception.

CBD should not be assumed to work the same way. The FDA label for the prescription medicine Epidiolex says its precise antiseizure mechanisms in humans are unknown and do not appear to depend on interaction with cannabinoid receptors. This does not establish that a retail product treats a condition. See how receptors and responses differ.78

Mechanism is not a clinical outcome

Studies of receptors, cells and animals can explain why researchers ask a question. They do not by themselves show that people feel better, function better or avoid a serious outcome. A clinical result belongs to the product, people, comparison, outcome and follow-up studied. Evidence for one regulated medicine does not automatically transfer to every product called cannabis or CBD.35

Approved products have narrow scope

FDA has approved particular cannabis-derived or cannabis-related medicines for defined indications, including purified CBD, dronabinol and nabilone. That does not make unapproved retail products equivalent to those medicines. FDA states that THC and CBD products are excluded from the federal dietary-supplement definition under the drug-exclusion provision; hemp-seed ingredients have a separate food history. Federal, state and local rules can differ.1526

Safety belongs beside benefit

THC can impair attention, reaction time and memory, and may cause anxiety, paranoia or other unwanted effects. CBD has different safety concerns, including liver injury identified during development of Epidiolex and possible medicine interactions. Risk depends on the product, amount, route, age, previous exposure, other substances and health. “Natural,” “hemp-derived” or “low THC” does not establish safety.436

Keep jurisdiction attached

An approval is a decision about a named product, indication, population and conditions of use. It is not a declaration that cannabis is broadly approved as a treatment. EU and member-state decisions can differ, as can rules for possession, prescribing and research. If a headline omits the jurisdiction and product, the claim is incomplete.12

Route changes the question

A cannabinoid can reach the body differently when inhaled, swallowed, absorbed through the mouth or applied to skin. Onset, absorption, peak concentration and duration can differ. A study of inhaled THC cannot automatically tell you what an edible will do. A claim about a cream needs evidence that its ingredient reaches the relevant tissue. Compare the product, route, timing and measurements before treating studies as equivalent.348

An indication-specific evidence map

Name the product before drawing a conclusion about the category. Purified cannabidiol (CBD) medicines such as Epidiolex or Epidyolex are prescription products studied and authorised for defined indications and populations; that evidence does not automatically apply to retail oils, gummies or topicals. In the United States, FDA also lists dronabinol products (Marinol and Syndros) and nabilone (Cesamet) as named prescription cannabinoid-related products with defined uses. Those U.S. examples do not establish authorization or labeling in another jurisdiction. A claim about sleep, anxiety, pain or wellbeing needs its own product, population, comparator, outcome and follow-up evidence rather than a general citation to cannabis.1265

A worked contrast: prescription CBD and retail CBD

A prescription CBD medicine is a defined formulation with specified manufacturing controls, pharmacokinetics, dosing instructions and clinical trials in named conditions. A retail CBD product may differ in concentration, route, contaminants, labelling accuracy and stability. The shared molecule does not make the evidence interchangeable. To evaluate a claim, ask which product was tested, how exposure was measured, what outcome was prespecified and what regulator record applies. This is not a conclusion that every retail product is harmful; it is a reason not to infer retail effectiveness or safety from a prescription trial.465

Five questions for a cannabinoid claim

Which compound and product were studied? Was it a purified, quality-controlled product or a variable extract? Who took part, what was it compared with and what was measured? What harms, interactions and follow-up limits were reported? Which regulator, country and use does an approval claim actually describe?35

The subjects, explained.

Substance profile

Cannabidiol (CBD).

A plain-language guide to cannabidiol: what the compound is, why products differ, and what human evidence can—and cannot—show.

9 min read

Questions in this field.

Explore specific questions.

Further reading

Trusted external resources selected to help explain this page. They open in a new tab.

Build the foundations.

Sources, kept close.

Selected supporting sources; this is not a complete literature review.

  1. FDA Regulation of Cannabis and Cannabis-Derived Products, Including CBDUS Food and Drug Administration · Regulator informationAccessed 2026-11-03
  2. Epidyolex: European public assessment reportEuropean Medicines Agency · Regulator product recordAccessed 2026-11-03
  3. Cannabis (Marijuana) and Cannabinoids: What You Need To KnowNIH / NCCIH · Official health informationAccessed 2026-11-03
  4. What You Need to Know About Products Containing CBDUS Food and Drug Administration · Regulator consumer safety informationAccessed 2026-11-03
  5. FDA and Cannabis: Research and Drug Approval ProcessUS Food and Drug Administration · Regulator research and approval informationAccessed 2026-11-03
  6. Epidyolex product informationEuropean Medicines Agency · Regulator product informationAccessed 2026-11-03
  7. Cannabis (Marijuana) Research Report — How does marijuana produce its effects?National Institute on Drug Abuse · Official scientific referenceAccess checked 2026-11-03 · NIDA research report inspected for anandamide, cannabinoid receptors and THC effects; a general explanation, not a trial of a particular product.
  8. Epidiolex (cannabidiol) prescribing informationU.S. Food and Drug Administration · U.S. prescription product labelAccess checked 2026-11-03 · Source date: 2025-06 · FDA label inspected for indicated ages, seizures, liver injury, sedation and interactions; confirm the current version before publication.
Explanation