It's been promoted by American football players and Hollywood stars. And now the legal cannabis product CBD (Cannabidiol) is gaining in popularity in the UK.
You might have seen the three letters on fizzy drinks, bottles of water, capsules and mint-flavoured sprays. These are CBD infused products on sale in corner shops, health stores and supermarkets.
But what is CBD and how does it differ from other forms of cannabis like cannabis oil and hemp?
CBD is a naturally occurring extract of cannabis. It can be extracted and mixed with an oil, often hemp seed or coconut oil.
It doesn't get you high like other parts of the cannabis plant and is taken by users for things like muscle aches, anxiety and even Post Traumatic Stress Disorder (PTSD).
Over the past year interest in CBD has grown massively and it has become a multi-million pound industry in a short space of time.
What is CBD?
CBD is one of the 115 chemical compounds, known as cannabinoids, that are found in the cannabis plant.
A new drink on the market called Green Monkey is believed to be the first carbonated CBD drink commercially available in the UK. WalesOnline has seen it on sale at a Spar store in Cardiff and bought a can to get a closer look.
What did Green Monkey taste like?
The bright green liquid looked like no other fizzy drink I've ever seen before.
It has a cloudy appearance and the initial fizz quickly dissipates, leaving behind a flat, hard to describe tasting drink.
It smelled like a combination of a cocktail and a soft drink and didn't taste like anything I've ever drank before. It left me with a dry mouth and strange after-taste.
It definitely drew a lot of attention in the office, mainly due to it's radioactive-like colour. But I have to admit I didn't finish the whole can, so I can't really say if it had any affect.
With the clever branding and eye-catching colour, I can see it getting a lot of attention.
The company said the product will be officially launched by February 1, although it is now available in a number of shops.
The back of the can I bought said it contained 10mg of CBD and recommends a maximum of two cans a day are consumed.
It states it is not for use by people under 18, and pregnant or lactating women should contact a doctor before use.
Green Monkey said the information on the can will be altered.
Green Monkey chief executive Serge Davies described CBD as a dark oil which is separated from other cannabis compounds such as the psycho-active THC which are "pushed out".
He said it's responsible for the relaxation effects from cannabis but is not psychoactive. The 'high' produced by cannabis instead comes from the compound THC.
CBD can come from two different cannabis plants, the hemp plant or the marijuana plant - which has far more THC.
Lloyds Pharmacy offer a range of CBD products, which are all derived from the whole hemp plant.
Cannabis oil is from the marijuana plant, which has higher levels of THC and lower levels of CBD.
Cannabis oil has been the subject of several high profile cases in recent years such as children with severe epilepsy who have been denied access to the substance to help control seizures.
What are the benefits of CBD?
Many users say using CBD helps with a number of issues including anxiety, depression and muscle pains.
Despite the claims, researchers have not yet been able to say for certain what specific benefits it can have.
According to the NHS, medical cannabis is a broad term for any sort of cannabis-based medicine used to relieve symptoms.
It said: "Many cannabis-based products are available to buy online, but their quality and content is not known. They may be illegal and potentially dangerous."
Some products that might claim to be medical cannabis, such as "CBD oil" or hemp oil, are available to buy legally as food supplements from health stores. But there's no guarantee these are of good quality or provide any health benefits.
The health service said it is "likely" that some cannabis-based products for sale online will be illegal to posses or supply.
Legal health stores also sell certain types of "pure CBD", but the NHS warn "there's no guarantee" they will be of good quality and as they only contain very small amounts of CBD it's not clear what effect they would have.
Mr Davies said: "In a primarily anecdotal sense people use it to relax, for insomnia and for aches and pains as well."
He added that there was a "growing body" of research behind the benefits of CBD.
MediPen, a Cardiff-based company exploring whether certain chemicals in cannabis can be used to stop the spread of lung cancer, said they had received "heartwarming" feedback from clients.
Jordan Owen, the managing director of the lab in Pontprennau, said the method of consuming CBD can impact how effective it is.
Why has CBD become so popular?
In Wales, Google searches for CBD have almost doubled in the last year.
A number of celebrity endorsements, from NFL players to Morgan Freeman, have also helped CBD become more popular.
The star actor reportedly started advocating CBD after a car crash in 2008 in which he used the product to help with the pain.
A number of other A-list celebrities from Mike Tyson to KISS' Gene Simmons are also reportedly fans of the product.
Although the legality of CBD is less clear across the US, with the law varying in some states, it has been described by CNN as "America's coolest food and drink ingredient".
It's now featured in a number of high end products including body lotion, face serum, lip balm and even coffee, olive oil and jam.
The Brightfield Group, a market research firm, said that the CBD market in the US had nearly doubled in size between 2017 and 2018.
The huge growth shows no sign of slowing either, with data resource Statista stating that by 2022 the CBD market in the US will be worth $1.15bn dollars.
CLEAR, the UK's largest membership-based cannabis policy group, said: "The market has been driven initially because of growing interest in the medical benefits of cannabis and the recognition that, within certain constraints, products derived from low-THC cannabis, legally grown under licence as industrial hemp, are a legal alternative.
"An important factor has been that CBD is most often consumed by placing a few drops of oil under the tongue.
"This has avoided the stigma of smoking a joint and is more in line with the way people perceive a medicine or health food."
Lloyds Pharmacy is believed to be the first high street pharmacy to sell CBD. It sells CBD products in oils, capsules and powders.
A spokeswoman said: "There is an increasing customer interest in CBD as well as concerns around the quality of some of the CBD products currently on the market.
"CBD products can be purchased online, however many of these sources are unregulated and may contain other ingredients which are not legal in the UK."
Green Monkey's chief executive Serge Davies believes the idea of cannabis has changed over the years and that this has helped its growth in popularity.
"There's a couple of reasons for its popularity, which has grown exponentially," he said.
"Perceptions of cannabis have changed over the past few years and a number of high-profile cases have helped that.
"I think that people are tending to do their own research now and not just following guidance. I do think there's some sort of trend at the moment, it's very much in vogue."
Mr Owen, from MediPen, added: "People are becoming far more aware of cannabis. We have been working very hard to break down those negative connotations of cannabis."
Is CBD oil legal?
Cannabis itself is a controlled drug under the Misuse of Drugs Act 1971.
While many of the more than 100 cannabinoids that make up cannabis are controlled, CBD is not.
This isn't a recent change, with industrial hemp long being grown in the UK. It is a strain of the cannabis plant, but contains little or no THC, but does contain CBD.
The Home Office said it would only issue licences for the cultivation of plants from approved seed types with a THC content not exceeding 0.2%.
According to Home Office guidance, CBD as an isolated substance in its pure form would not be a controlled substance.
If a CBD product did contain any controlled cannabinoids such as THC, then it is "highly likely" it would be controlled.
The guidances states: "It is our understanding that it is very difficult to isolate pure CBD, and in our experience many products in fact do not fully disclose their contents or provide a full spectrum analysis at an appropriate level of sensitivity to accurately and consistently determine their true content or control status."
If a company claims their product has any clinical or medical benefits, then it may also be subject to further licensing and control.
