Cannabinoids Explained: THC, CBD, CBG, CBN & More | PatientsCann UK

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Understanding Cannabinoids

Cannabinoids are the active compounds in cannabis. They are the reason a cannabis medicine can ease pain, calm the mind, or help with sleep. This guide explains what they are, how they work in your body, and why heating the plant changes everything.

11 cannabinoids Interactive receptor map Accurate chemical structures

What are cannabinoids?

Cannabinoids are a family of natural compounds made by the cannabis plant. Scientists have found more than 100 of them. They are the part of the plant that makes it useful as a medicine.

Each cannabinoid has its own job. THC eases pain and sickness but also causes the "high". CBD is calming and does not make you high. Others, like CBG and CBN, are being studied for focus, sleep and much more.

Your body already makes its own cannabinoid-like chemicals. Plant cannabinoids work by borrowing the same network in your body. Scientists call it the endocannabinoid system, or ECS for short.

Cannabinoids rarely work alone

Alongside the aroma compounds called terpenes, cannabinoids seem to work better together than apart. Scientists call this the "entourage effect". It is one reason a whole-plant medicine can feel different from a single pure cannabinoid. Learn more on our terpenes guide.

Interactive

How Cannabinoids Work in the Body

Your endocannabinoid system has two main "locks", called receptors: CB1 and CB2. Cannabinoids are the "keys". CB1 sits mostly in the brain and nerves. CB2 sits mostly in the immune system and around the body. Pick a cannabinoid below to see which locks it fits, and what that might mean for you.

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Raw vs Heated: Why Cannabis Must Be Warmed

Here is something that surprises most people: raw cannabis will not get you high. The plant does not make THC or CBD directly. It makes their acid forms first, called THCA and CBDA. Only when you add heat, by vaping, smoking or cooking, do these acids lose a tiny piece (a carbon dioxide molecule) and turn into THC and CBD. This is called decarboxylation. Follow the pathway, tap any molecule to see its structure, then press Apply heat.

The plant makes acids (left). Heat turns them into the cannabinoids you know (right).

At a glance

THC vs CBD: The Two You Hear About Most

THC and CBD come from the same plant and look almost identical under a microscope, yet they behave very differently in the body. Here is the simple version.

THC

Delta-9-tetrahydrocannabinol

Makes you high?
Yes. It switches on CB1 in the brain.
Mainly used for
Pain, muscle spasm, nausea, appetite and sleep.
How it works
Directly activates the CB1 and CB2 receptors.
UK status
Prescription only, from a specialist doctor.
Watch for
Anxiety, a racing heart or dizziness at higher doses.

CBD

Cannabidiol

Makes you high?
No. It barely touches CB1.
Mainly used for
Anxiety, epilepsy, inflammation and calm.
How it works
Acts mostly on other targets, and softens THC.
UK status
Low-THC CBD sold as a supplement; medical CBD is prescribed.
Watch for
Usually well tolerated; can interact with some medicines.

Full library

The Cannabinoid Family

Select any card to open the full profile, with its accurate chemical structure, how it works, what the research says, and safety notes. Use the filters to narrow the list.

    Questions

    Cannabinoids: Your Questions Answered

    What is the difference between THC and CBD?
    THC is intoxicating: it switches on the CB1 receptor in the brain, which causes the "high" and also eases pain and nausea. CBD is non-intoxicating: it barely touches CB1 and works mostly on other targets, and is studied for anxiety, epilepsy and inflammation. Many patients use a medicine that contains both.
    Which cannabinoid gets you high?
    Delta-9-THC is the one responsible for the "high". Delta-8-THC and CBN are only mildly intoxicating. CBD, CBG, CBC, THCV, CBDV and the raw acids (THCA, CBDA, CBGA) do not make you high.
    Do I need a prescription for cannabinoids in the UK?
    Cannabis medicines that contain THC can only be prescribed by a specialist doctor on the General Medical Council's Specialist Register. Some low-THC CBD products are sold in shops as food supplements, but a medical cannabis prescription is a different thing. Our Start Your Journey guide explains how to access one.
    What is the endocannabinoid system?
    It is a network of receptors, natural chemicals and enzymes found all over the body. Its two main receptors are CB1, mostly in the brain and nerves, and CB2, mostly in the immune system. It helps to keep things like mood, sleep, appetite and pain in balance. Plant cannabinoids work by acting on this same system.
    Why does cannabis need to be heated?
    Raw cannabis contains acid forms such as THCA and CBDA, which are not intoxicating. Heating them (by vaping, smoking or cooking) removes a carbon dioxide molecule and turns them into THC and CBD. This is called decarboxylation. It is why eating raw flower will not have the same effect as a heated product.
    Are cannabinoids addictive?
    THC can lead to dependence in some people, especially with heavy, long-term use. Non-intoxicating cannabinoids like CBD are not thought to be addictive. Your prescriber will help you use your medicine safely. Never change your dose without speaking to them first.
    What is the entourage effect?
    It is the idea that cannabinoids and terpenes work better as a team than on their own. For example, CBD and certain terpenes may shape and soften the effects of THC. It is still being researched, but it helps explain why whole-plant medicines can feel different from single pure compounds.
    Sources: Molecular structures drawn from PubChem canonical data (NCBI, 2025). Receptor and effect summaries simplified from Pertwee (2008), Russo (2011), Izzo et al. (2009) and Morales et al. (2017). Boiling points and formulas from PubChem. This page simplifies complex science for patients and is not a substitute for advice from your prescriber.

    References

    1. Baram, L. et al. (2022) 'Major cannabis terpenes, applied individually and in combination, activate endogenous cannabinoid CB1 and CB2 receptors', Frontiers in Pharmacology, 13, 1040962. doi: 10.3389/fphar.2022.1040962.
    2. ElSohly, M.A. and Gul, W. (2014) 'Constituents of Cannabis sativa', in Pertwee, R. (ed.) Handbook of Cannabis. Oxford: Oxford University Press, pp. 3-22.
    3. Gaoni, Y. and Mechoulam, R. (1964) 'Isolation, structure, and partial synthesis of an active constituent of hashish', Journal of the American Chemical Society, 86(8), pp. 1646-1647. doi: 10.1021/ja01062a046.
    4. Izzo, A.A. et al. (2009) 'Non-psychotropic plant cannabinoids: new therapeutic opportunities from an ancient herb', Trends in Pharmacological Sciences, 30(10), pp. 515-527. doi: 10.1016/j.tips.2009.07.006.
    5. Morales, P., Hurst, D.P. and Reggio, P.H. (2017) 'Molecular targets of the phytocannabinoids: a complex picture', Progress in the Chemistry of Organic Natural Products, 103, pp. 103-131. doi: 10.1007/978-3-319-45541-9_4.
    6. National Center for Biotechnology Information (2025) PubChem Compound Database. Bethesda: U.S. National Library of Medicine. Available at: https://pubchem.ncbi.nlm.nih.gov (Accessed: 29 July 2026).
    7. Pertwee, R.G. (2008) 'The diverse CB1 and CB2 receptor pharmacology of three plant cannabinoids: delta-9-tetrahydrocannabinol, cannabidiol and delta-9-tetrahydrocannabivarin', British Journal of Pharmacology, 153(2), pp. 199-215. doi: 10.1038/sj.bjp.0707442.
    8. Russo, E.B. (2011) 'Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects', British Journal of Pharmacology, 163(7), pp. 1344-1364. doi: 10.1111/j.1476-5381.2011.01238.x.
    9. UK Government (2018) The Misuse of Drugs (Amendments) (Cannabis and Licence Fees) (England, Wales and Scotland) Regulations 2018. London: The Stationery Office.
    Important: This page is for education only. It is not medical advice. Cannabinoid research is still developing, and many studies have been done in cells or animals rather than people. Always speak to your prescriber before changing your treatment. PatientsCann UK does not recommend any specific cannabis product.