Cannabidiol (CBD) is a phytocannabinoid discovered in 1940. It is one of 113 identified cannabinoids in cannabis plants, along with tetrahydrocannabinol (THC), and accounts for up to 40% of the plants extract. As of 2019, clinical research on CBD included studies related to anxiety, cognition, movement disorders, and pain, but there is insufficient high-quality evidence that cannabidiol is effective for these conditions. Nevertheless, CBD is a popular herbal dietary supplement, widely promoted with unproven claims of particular therapeutic benefits. The global market size for CBD was predicted to exceed US$47 billion by 2028.Cannabidiol can be taken internally in multiple ways, including by inhaling cannabis smoke or vapor, by mouth, and as an aerosol spray into the cheek. It may be supplied as CBD oil containing only CBD as the active ingredient (excluding tetrahydrocannabinol [THC] or terpenes), CBD-dominant hemp extract oil, capsules, dried cannabis, or prescription liquid solution. CBD does not have the same psychoactivity as THC, and will negate the psychoactive effects of THC on the body if both are present. As of 2018, the mechanism of action for its biological effects has not been determined. Unlike THC, which acts on the cannabinoid receptor type 1 (CB1) as a partial agonist, CBD instead is a negative allosteric modulator of CB1 receptors.In the United States, the cannabidiol drug Epidiolex was approved by the Food and Drug Administration in 2018 for the treatment of two epilepsy disorders.
United Kingdom
Cannabidiol, in an oral-mucosal spray formulation combined with delta-9-tetrahydrocannabinol, is a product available by prescription for the relief of severe spasticity due to multiple sclerosis (where other anti-spasmodics have not been effective).Until 2017, products containing cannabidiol marketed for medical purposes were classed as medicines by the UK regulatory body, the Medicines and Healthcare products Regulatory Agency (MHRA), and could not be marketed without regulatory approval for the medical claims. As of 2018, cannabis oil is legal to possess, buy, and sell in the UK, providing the product does not contain more than 1 milligram of THC and is not advertised as providing a medicinal benefit.In January 2019, the UK Food Standards Agency indicated it would regard CBD products, including CBD oil, as a novel food having no history of use before May 1997, and stated that such products must have authorisation and proven safety before being marketed. The deadline for companies with existing products to submit a full and validated novel foods application with the FSA is 31 March 2021; failure to do so before this date will exclude those companies from selling CBD. New products containing CBD after this deadline will require a fully approved application.In February 2020, the UK FSA advised vulnerable people, such as pregnant women, breastfeeding mothers, and those already taking medication for other medical concerns not to take CBD. The FSA further recommended that healthy adults should not consume more than 70 mg CBD per day.