EducationThe science behind CBD and what it does to your body

The science behind CBD and what it does to your body

9 min read

Lucy MacKinnon

The science behind CBD and what it does to your body
CBD, short for cannabidiol, is one of the main chemical compounds found in the cannabis plant family, and can be found in particularly high concentrations in hemp plants. Administered to evoke a variety of potential therapeutic and health effects for thousands of years across the globe, CBD is now widely seen as a possible therapeutic option to aid anxiety, pain, sleep, and epilepsy.


For close to a century, cannabis (and CBD along with it) has been vilified, misunderstood, and shoved to the back of the medicinal cue. But now, because of scientific advancements and pharmacological developments, CBD is slowly showing huge promise as an extremely versatile therapeutic compound. In the past decade, we have seen its application as a common ingredient in health and wellness products.

These days, CBD is typically extracted from hemp plants to be sold as isolate, or manufactured into broad-spectrum or full-spectrum products available in oil, edible and topical forms.

To answer some of the most frequently asked questions about cannabidiol such as ‘What does CBD do?’ or ‘What is CBD administered for’ we’ve put together this guide to help you understand the science behind CBD, what it may potentially help with in terms of your health, and what the research says about its possible therapeutic effects on human health.

What does CBD do?

Although CBD and THC share a similar chemical structure, made up of 21 carbon atoms, 30 hydrogen atoms and 2 oxygen atoms, their slight chemical differences are the reason for their differing effects on the human body. Instead of binding directly to cannabinoid receptors to trigger responses, like THC, cannabidiol is believed to interact with the endocannabinoid system indirectly.

With new evidence to suggest CBD has a negligible affinity to both types of cannabinoid receptors, this cannabis compound is believed to be an allosteric modulator, because it impacts or influences the interaction between receptors and other molecules. 

Instead of binding directly to its receptors, CBD appears to promote the longevity of the natural endocannabinoids that interact with a host of receptors by reducing their enzymatic breakdown.

As well as being able to delay the uptake of naturally produced cannabinoids, CBD may also have the ability to mimic them to interact with their receptors. This includes TRPV1 receptors, which are known to influence inflammation and pain perception, as well as serotonin receptors, a type of G-coupled protein receptor that impacts anxiety, appetite, and addiction, and GRP55 which oversees the regulation of many physiological processes including blood pressure and bone density.

Scientists have also discovered that CBD may reduce some of the psychoactive or intoxicating experiences of THC when the two are taken in combination. This could be because, instead of binding with CB1 receptors in the brain, cannabidiol has been shown to alter the shape of the CB1 receptor, reducing their binding affinity with THC which in turn may reduce the likelihood of experiencing the euphoria or high associated with cannabis.

With the possible ability to influence many different neurotransmitters around the body which trigger a wide variety of therapeutic results, it is no surprise CBD products are becoming increasingly administered in the medicinal scene. Research potentially shows that patients living with sleep and skin disorders, and anxiety, as well as those with chronic pain, inflammation, and certain forms of epilepsy, could possibly benefit from CBD treatments.

Benefits of CBD

One of the most thoroughly investigated, and clinically proven benefits of CBD, is that it may offer anticonvulsant properties. A 2015 study into paediatric epilepsy analysed 117 children with Lennox-Gastaut Syndrome (LGS) and found that their seizure rates fell by an average of 85% when taking CBD-enriched cannabis products. 

Other promising results for CBD in the treatment of this type of epilepsy can be seen in a 2018 double-blind, placebo-controlled trial that investigated CBD's effects on both adults and children with LGS. In this trial, patients that received 20 mg of CBD for every kilogram of their body weight reported a drop in seizure frequency of 41.9% when the phytocannabinoid was added to their daily routine alongside their prescribed antiepileptic medications.

Studies like this are the reason CBD and other cannabis-based medications are approved for administration in the treatment of epilepsy in a huge range of countries. In the UK, there is a licensed and approved form of CBD (marketed medicinally as Epidyolex) that can be prescribed by specialist doctors, for treatment of rare forms of epilepsy. Although Epidyolex has proven to aid in the treatment of both Lennox Gastaut Syndrome and Dravet Syndrome, very few NHS prescriptions have ever been issued. We will hopefully see this change in the coming years. 

Cannabidiol’s potential benefits for pain management have also been explored. In 2018 a 12-week-long randomised, double-blind, placebo-controlled trial discovered that the application of a CBD gel had the potential to improve the knee pains experienced by patients with osteoarthritis. Evaluated against the WOMAC scale, patients' worst pain levels were improved by over 52% on a weekly average, after 250 mg of CBD had been topically applied to the painful area.

A reduction in anxiety levels was also noted in a double-blind, placebo-controlled trial that tested the possible effects of CBD on patients with an addiction to heroin. As well as experiencing a reduction in cravings, after the acute administration of CBD, the anxiety symptoms felt by heroin users had significantly decreased. These findings remained stable during a week-long evaluation period.

Another benefit of CBD is the fact that it may offer a positive influence on skin conditions. As well as having anti-inflammatory properties, cannabidiol has also shown its potential as an effective antibiotic that can fight bacterial strains such as MRSA. CBD is also a common ingredient in cosmetics due to its effects on sebum regulation, which can aid in the treatment of acne. Sleep has also been seen to potentially improve when using CBD. One study in 2019 showed that 91% of PTSD patients reported a reduction in the severity of their symptoms when using CBD, including a reduction in disturbed sleep and a significant improvement in sleep quality.

Side effects of CBD

Although systematic reviews of CBD studies demonstrate very few instances of serious side effects have been reported in both clinical trials and real-world data collection, as with any wellness or health product, it is important that patients are aware of their possibility.

The most frequently felt side effects or adverse drug reactions experienced after consuming cannabidiol are relatively rare and aren’t believed to seriously affect health. Reported minor and manageable side effects include feeling tired or irritable, slightly nauseous or lightheaded and feeling thirsty or experiencing ‘dry mouth’.

Like 60% of all clinically prescribed medications, CBD is processed in the liver by an enzyme called CYP3A4. When cannabidiol is taken alongside medications like Ketoconazole and Clarithrommyan, the CYP3A4 has a lot of work to do, breaking down drugs, so they can then be absorbed into the bloodstream. 

Sometimes CBD is processed first, which can impede or delay the uptake of other medications, and in other cases, this enzyme interacts with prescription medications first, which allows CBD to stay pharmaceutically active for long periods of time before it is broken down.

CBD products

In order to produce these effects, cannabidiol is extracted from the cannabis and hemp plants in various different ways. Two of the most popular methods are Supercritical CO2 Extraction; where cannabinoids are extracted using pressurised carbon dioxide allowing for a very pure end product with a heavy price tag; and Ethanol Extraction, that uses alcohol to draw out cannabis compounds in a cheaper and more efficient fashion, but carries a risk of alcoholic contamination. Once extracted from the plant as cannabidiol isolate, CBD can be mixed with carrier oils and other excipients that add other therapeutic properties, aroma, or flavours and made into other product forms such as creams, oils, foods, drinks, and vapes.

After their product transformations, cannabidiol and other compounds can then enter the system after being administered topically, sublingually, or by being ingested or inhaled. According to the latest Prohibition Partners report into CBD administration across Europe, CBD oils and tinctures are the most popular treatment form, with 56% of the 955 users surveyed choosing this method within the last year.

CBD oils and tinctures can either be administered sublingually; where they are held under the tongue and CBD is absorbed through membranes in the mouth; or mixed in with food or drinks, causing the CBD to filter through the stomach and liver. Some CBD oils are designed to be vaped, which allows cannabidiol to enter the lungs and into the bloodstream.

The Prohibition Partners report also demonstrates that product preference differs amongst different demographics. Whilst oils and tinctures seem to have been most frequently taken across every age range, capsules and pills were generally favoured by older generations, and younger users reported more instances of vaping and dried flowers.

When deciding what type of CBD product may best suit you, it is important to consult your doctor and consider a number of factors, including:

  • Any medications you may currently take that could interact with cannabis compounds
  • The speed and longevity of the relief that you require
  • Your preferred administration method
  • How CBD would be incorporated into your daily routine


In 2017 The Expert Committee on Drug Dependence from the World Health Organisation announced CBD “does not appear to have abuse potential, or cause harm”. But, as always, it is important to make your doctor aware of your interest in CBD and seek their professional advice and guidance.

We hope that this article helped to answer some of the questions you may have had about CBD and how it works within the body. While you’re here, why not check out our other cannabinoid content to learn more about their benefits, legal status and clinical applications.

Releaf understands that medical cannabis can be life-changing for many people. That's why we offer tailored monthly packages based on your cannabis prescription, specialist consultations for medical cannabis, and a unique medical cannabis card for protection.

It is important to seek medical advice before starting any new treatments. The patient advisors at Releaf are available to provide expert advice and support. Alternatively, click here to book a consultation with one of our specialist doctors.

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With five years of journalism and healthcare content creation under her belt, Lucy strives to improve medical cannabis awareness and access in the UK by producing high quality, credible content.

Our articles are written by experts and reviewed by medical professionals or compliance specialists. Adhering to stringent sourcing guidelines, we reference peer-reviewed studies and scholarly research. View our editorial policy.

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