Class B or Psychoactive Substances

Synthetic and semi-synthetic cannabinoids

Also called: HHC, K2, Mamba, Spice, Synthetic cannabis, Synthetic marijuana, THC vape (since these products may contain synthetic and semi-synthetic cannabinoids instead)

Synthetic cannabinoids are artificial chemicals that act on the cannabinoid receptors in the brain. Semi-synthetic cannabinoids are chemicals derived from the cannabis plant but altered so that they end up being chemicals that do not occur naturally. There are dozens of these chemicals, some have similar effects to cannabis, some are very different, and some of them can be very harmful.

Vapes purchased from illegal sources have been found to contain synthetic and semi-synthetic cannabinoids. These have contributed to many overdoses in the UK, some resulting in people being taken to hospital.

Some drugs are increasingly cut with dangerous synthetic opioids like nitazenes, which have killed 100s of people in the UK in the past year. This is happening in a wide range of drugs, not just heroin, and you can never really know what is in any street or counterfeit drug. Find out more about the risks and what to do here.

There is a wide list of products and brand names that is constantly changing. These are not necessarily associated with a particular drug or used consistently.

Quick info

How the drug works varies from person to person

How you might feel

Happy, relaxed, talkative and/or anxious, paranoid, sedated.

Effects on your body

Effects can be similar to cannabis but can also be stronger or more unpleasant.

How long it takes to work

Usually smoked or vaped so pretty immediate. Slower if swallowed.

How long the effects last

Varies from about 1 to 6 hours depending on the specific chemical.

Easy to want more and take larger doses.
Mental health can get worse.
Psychotic episodes can be triggered, usually in those already susceptible, and last for weeks.

If you or someone else needs urgent help after taking drugs or drinking, call 999 for an ambulance. Tell the crew everything you know. It could save their life.

Call 999 What else to do in an emergency

How does it make you feel?

Since synthetic and semi-synthetic cannabinoids act on the same neuron receptors as cannabis, the effects - good and bad – can be similar. Some users will feel happy and relaxed, may get the giggles, feel hunger pangs and become very talkative. Others mainly feel ill or paranoid. However, synthetic and semi-synthetic cannabinoids are often more potent than natural cannabis , so it's easier to use too much and experience unpleasant and harmful effects.

Typical effects include:

Feelings of being happy, euphoric and relaxed, with some people getting the giggles, feeling hunger pangs and becoming very talkative, while others get more drowsy.
Mood and perception can change, and concentration and coordination may become difficult. Synthetic and semi-synthetic cannabinoids, possibly because of their potency, are more likely to be associated with hallucinations than natural cannabis.
Some will have quite bad reactions, such as paranoia, panic attacks and forgetfulness.

Physical health risks

Reported side-effects from using synthetic and semi-synthetic cannabinoids include:

feelings of light-headedness, dizziness, confusion and tiredness
feeling excited, agitated and aggressive
mood swings
anxiety and paranoia
suicidal thoughts
memory problems and amnesia
nausea and vomiting
hot flushes
increased heart rate and blood pressure, which may cause chest pains and damage your heart and even cause a heart attack
excessive sweating
fingers, toes or muscles feel numb and tingly
tremors, seizures and fits

Other risks for synthetic and semi-synthetic cannabinoids:

Research suggests that there may be an association between using synthetic cannabinoids and acute kidney injury.
Many cannabinoids have a chemical structure that is similar to serotonin, a natural chemical found in the body. It’s been suggested that there’s a risk that synthetic and semi-synthetic cannabinoids could overstimulate the serotonin system (called serotonin syndrome), which can result in high fever, rapid pulse, sweating, agitation, confusion, convulsions, organ failure, coma and even death.
Because of the way that smoking mixtures are made, there can be differences in the concentration of synthetic and semi-synthetic cannabinoids in individual packets and between different batches. Similarly, there is no way of knowing how strong liquids to be vaped are going to be. You can never be 100% sure of how powerful a dose you are going to take.
We know that there have been a number of deaths associated with the use of synthetic cannabinoids, either on their own or with other substances. There may also be risks from smoking the plant material itself – as occurs with tobacco and cannabis smoking.
Semi-synthetic cannabinoids have appeared much more recently and so there is much less information about their associated harms.

Mental health risks

Synthetic and semi-synthetic cannabinoids are more likely to be associated with hallucinations than natural cannabis.
Use of synthetic and semi-synthetic cannabinoids can cause psychotic episodes, which in extreme cases could last for weeks.
Regular use could cause a relapse of mental health illness or increase the risk of developing a mental illness, especially if you have a family history of mental illness.

What are Synthetic and semi-synthetic cannabinoids cut with?

It’s more likely that synthetic and semi-synthetic cannabinoids are used to cut other substances. They may be used in products reported to contain THC such as THC vapes or THC vape liquids.

Synthetic and semi-synthetic cannabinoids are usually sold in 'herbal' smoking mixtures. Any dried herbs, vegetable matter or plant cuttings can be mixed or sprayed with these substances to make smoking mixtures.

It's also possible that the vegetable matter itself may produce an unwanted effect or be covered in a toxic substance, such as a pesticide, or there may be residues of the solvents, such as acetone and methanol, used in the mixing/spraying process, remaining on the smoking mixture.

There can be differences in the concentration of synthetic and semi-synthetic cannabinoids in between different batches and packets. This could be because the mixing or spraying missed some of the smoking mixture or over-sprayed some of it.

The chemical composition of synthetic and semi-synthetic cannabinoids and the ingredients of smoking mixtures are changing all the time, so you can never be sure of what you're getting, how powerful it is, and how it could affect you.

What does it look like?

In their pure form, synthetic and semi-synthetic cannabinoids are either solids or oils. They might then be added, usually by spraying, to dried herbs or other vegetable matter to make a smoking mixture (so that it looks more like real herbal cannabis). Sometimes they have also been added to cannabis. Increasingly, they are added to liquids sold to be vaped, or added to sweets and sold as edibles sometimes called gummies.

The smoking mixtures can be packaged in small, often colourful sachets with labels or they could be in plain plastic bags. Vape liquids that contain synthetic and semi-synthetic cannabinoids are commonly mis-sold as ‘THC liquids.’ The same goes for ‘THC gummies.’

Sweets may look the same as high street brands so they are more appealing, especially to children and young people.

There are many different names given to herbal smoking mixtures, some of the most common are listed in the 'Also called' section at the top of the page.

It is common for different brands to contain the same synthetic or semi-synthetic cannabinoids.

Synthetic and semi-synthetic cannabinoids are normally used in a similar way to cannabis and its extracts:

They can be mixed with tobacco, rolled up into a spliff or joint, and then smoked.
They can be smoked without tobacco using a pipe or bong.
As vapes have become more widely available, people may use e-liquids containing synthetic or semi-synthetic cannabinoids that are then used with vaping devices.
They can also be swallowed, eaten with food or made into a drink.
There are increasing reports of ‘cannabis edibles’, looking like sweets such as gummies, lollipops, and other sweets. These sometimes contain synthetic or semi-synthetic cannabinoids instead of cannabis.

Can you get addicted?

Research suggests that you can become dependent on synthetic and semi-synthetic cannabinoids, especially if you use them regularly. Whether or not you’re dependent will be influenced by a number of factors, including how long you've been using it, how much you use and whether you are just more prone to becoming dependent.

If you have used synthetic or semi-synthetic cannabinoids regularly you could find it difficult to stop using and you might experience psychological and physical withdrawals when you do stop. The withdrawals can include cravings for synthetic or semi-synthetic cannabinoids, irritability, mood changes, loss of appetite, weight loss, difficulty sleeping and even sweating, shaking and diarrhoea.

Class: B or Psychoactive Substances

Synthetic cannabinoids or semi-synthetic cannabinoids covered by the Misuse of Drugs Act

Most synthetic cannabinoids are Class B drugs, which means they are illegal to have for yourself, give away or sell
Possession can get you up to 5 years in prison, an unlimited fine or both.
Supplying someone else, even your friends, can get you up to 14 years in prison, an unlimited fine or both.

Synthetic or semi-synthetic cannabinoids covered by the Psychoactive Substances Act

Synthetic cannabinoids that are not Class B and semi-synthetic cannabinoids are covered by the 2016 Psychoactive Substances Act, which means they are illegal to give away or sell.
Supply and production can get you up to 7 years in prison, a fine or both
There’s no penalty for possession, unless you’re in prison.

Like drink-driving, driving when high is dangerous and illegal. If you’re caught driving under the influence, you may receive a heavy fine, driving ban, or prison sentence.

If the police catch people supplying illegal drugs in a home, club, bar or hostel, they can potentially prosecute the landlord, club owner or any other person concerned in the management of the premises.

Additional law details

Synthetic cannabinoids or semi-synthetic cannabinoids and the law

Although some synthetic cannabinoids were legal in the past, many have been illegal for some time. Most synthetic cannabinoids – and any mixtures that contain them – are Class B drugs and are illegal to have, give away or sell.
It’s important to realise that since 26 May 2016, when the Psychoactive Substances Act came into effect, none of these drugs are legal to produce, supply or import (even for personal use, e.g., over the internet) for human consumption.
Synthetic cannabinoids that are not controlled under Class B of the Misuse of Drugs Act and semi-synthetic cannabinoids are subject to the Psychoactive Substances Act 2016.

Worried about Synthetic and semi-synthetic cannabinoids — yours or someone else's?

Worried about your own use

Honest, confidential advice and the next steps you can take.

Get advice

Find support near you

Free, local drug treatment and support services.

Search by area

Call FRANK: 0300 123 6600 Or text 82111

Everything you tell FRANK is confidential. We're here to help, not judge.

Synthetic and semi-synthetic cannabinoids