Sarah Dumont-Gale June 03, 2019

Cannabidiol, or CBD, is increasingly popular, and is taken to support health in a number of different ways. But what exactly is CBD, what is its relation to cannabis, hemp and marijuana and why is it legal?

What are cannabinoids?

Cannabinoids are chemical compounds that interact with receptors found in the body's endocannabinoid system (see below). The cannabis plant is known to produce around 140 naturally occurring cannabinoids,1 with CBD and THC being the most extensively researched.


CBD and THC are similar molecules, with both containing 21 carbon atoms, 30 hydrogen atoms and 2 oxygen atoms. However, the arrangement of the atoms are slightly different between the two compounds, which can account for the different impacts they have on the human body.

CBD, also known as cannabidiol, is non-intoxicating, non-addictive and does not have any psychoactive effects. It has an excellent safety profile and is generally well tolerated even at high doses2. What's more, CBD is not classed as a drug and is currently legal to sell in the UK as a food supplement. There may be a change to its classification in the near future to a novel food - see our CBD regulation changes FAQ. However, in the meantime, it remains on sale from supplement companies such as Healthspan.

THC stands for tetrahydrocannabinol and is responsible for the 'high' or euphoric feeling that is commonly associated with marijuana or weed. It achieves this effect by binding to the cannabinoid receptors in the brain which affect pleasure, coordination and cognitive function. THC carries an increased risk of adverse events, and is classed as a controlled substance in the UK that is legally regulated.

Cannabis, hemp & marijuana

Both CBD and THC are sourced from cannabis, which can add to the confusion around both CBD's legality and why it doesn't produce a 'high'.

Different cannabis plants contain different levels of THC and CBD. Typically, CBD is extracted from the aerial (above ground) parts of the hemp plant. These parts contain very low levels of THC: less than 0.2%, in fact. In the EU, CBD is extracted from the species Cannabis sativa, which is more commonly referred to as industrial hemp.

Marijuana is sourced from a different cannabis species called Cannabis indica. Cannabis plants used for marijuana are bred to contain a high THC content, and these plants are legally regulated as a controlled drug.

The endocannabinoid system

The endocannabinoid system helps to regulate digestive function, cardiovascular activity, hormone control, immune function and pain perception in the body. It is made up of cannabinoid receptors found all over the body, the most important of which are CB1 and CB2. The body produces its own cannabinoids that interact with these receptors, but the receptors will also respond to the cannabinoids found in cannabis.

THC has the capacity to bind to both CB1 and CB2 receptors, which leads to its psychoactive effects, but CBD does not. Instead, CBD has been shown to increase the action of the cannabinoid anandamide - the so-called 'bliss molecule', which is made within the body. THC and CBD predominantly have opposite effects and CBD has been shown to be able to offset some of the psychoactive effects of THC.

At a glance: CBD versus THC

  • CBD is typically sourced from industrial hemp and is neither intoxicating nor addictive, and doesn't cause any psychoactive effects. THC is sourced from marijuana and causes a 'high' or sense of euphoria.
  • THC binds to CB1 and CB2 receptors, causing psychoactive effects, whereas CBD increases levels of anandamide.3
  • CBD has an excellent safety profile and is generally well tolerated at high doses. THC carries an increased risk of adverse effects.
  • It is legal to sell CBD as a food supplement, but THC is classed as a controlled substance.

1 Freeman, T.P., Hindocha, C., Green, S.F. and Bloomfield, M.A. (2019). Medicinal use of cannabis based products and cannabinoids, BMJ
2 Taylor, L., Gidal, B., Blakey, G., Tayo, B. and Morrison, G. (2018). A phase I, randomized, double-blind, placebo-controlled, single ascending dose, multiple dose, and food effect trial of the safety, tolerability and pharmacokinetics of highly purified cannabidiol in healthy subjects, CNS drugs
3 Leweke, F M, Piomelli, D, Pahlisch, F, Muhl, D, Gerth, C W, Hoyer, C, Klosterkötter, J, Hellmich, M, Koethe, D (2012). Cannabidiol enhances anandamide signaling and alleviates psychotic symptoms of schizophrenia, Translational Psychiatry


Nothing beats a healthy, balanced diet to provide all the nutrients we need. But when this isn't possible, supplements can help. This article isn't intended to replace medical advice. Please consult your healthcare professional before trying supplements or herbal medicines.



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