This is an abridged version of an 18-page ketamine resource used across our services since July 2025, including a use severity audit and CBT exercises to encourage reflection.

What is ketamine & how does it work?

Ketamine is a dissociative drug with psychedelic properties, used for a wide range of sometimes paradoxical reasons: to dissociate; to socialise; to relax; to stimulate or stay awake; easing a stimulant comedown; to dampen difficult emotions; for self-reflection; satisfying cravings or impulse; boredom; celebration; routine; frustration or anger; stress; anxiety; depression; self-medication of mental health symptoms or pain; self-sabotage or seeking oblivion.

As an anaesthetic, it is used in hospitals to numb pain for babies, older adults and people allergic to morphine. Unlike many other anaesthetics, ketamine doesn’t significantly reduce your breathing or heart rate, and in fact small doses can slightly increase your pulse and blood pressure.

Ketamine has a very steep tolerance response curve, meaning people who use regularly end up doing a lot more. People who have a tolerance will experience fewer psychedelic effects.

Sources, shapes & strengths

Some illicit ketamine is diverted from medical supplies imported into Europe. Some batches are made off the books by corrupt pharmaceutical labs and then imported illegally. Others are manufactured in illicit labs, for example in South East Asia.

Most ketamine crystals are shards (either short or long) but they can also look like sand, rocks or powder.

The strength and effects of different batches vary widely. It can make you feel sleepy, trippy or energetic in sometimes unpredictable ways. How you feel and your surrounding environment also influence your experience.

Most batches test as only ketamine. 9 analogues have been detected in ketamine seized by police in the UK so far, however these are likely a tiny minority of batches in the UK, particularly since the price has dropped. Analogues almost never appear within test results from harm reduction organisations such as WEDINOS or The Loop. Some bulking agents aren’t in testing libraries yet, and we do not know the extent to which ketamine is being cut with inert substances. Testing data from Europe strongly suggests that the ‘s-isomer’ labels given to some batches are fake marketing.

Top tips for reducing harm

If you want to stay safer when using ketamine:

• Start with a small amount when you have a new batch
• Wait until you’ve fully sobered up before taking more (eg 90 minutes)
• Avoid doing more than a bump in public spaces
• Crush your crystals properly and rinse with saline before bed to maintain your nose
• If you tend to do large lines, cut them up into several smaller ones and wait a few minutes between each
• Don’t assume people have the same tolerance as you – let them dose themselves
• Never drive or swim – discoordination will put you and others at risk

Be extra careful if your ket:

• Looks or smells or unusual
• Takes longer than usual to kick in
• Is overstimulating or unusually sedating

You can test your ket at home with a reagent kit. The Morris test is particularly useful. Reagent kits can only indicate if ketamine is present. Test strips can check if it’s been mixed with specific drugs like medetomidine or nitazenes. You can access lab testing by mailing a sample to WEDINOS but there is a bit of a wait for results.

If something feels unpleasant, it is always safer to chuck it down the sink.

Your brain on ketamine

Ketamine acts on NDMA receptors in your brain, affecting wakefulness and thought processes. Ketamine also disrupts communication between the brain and body, leading to discoordination.

Long term regular ketamine use can affect the overall volume and integrity of white and grey matter in the brain. This affects cognition. Long term regular use can also reduce the size of your hippocampus, the part of your brain which deals with:

• Memory
• Emotions
• Decision-making
• Long term planning

Ketamine & mental health

Taking ketamine, particularly large amounts, can cause short-term mental health difficulties, which mostly wear off once the effects of ketamine have passed. These include:

• Intense negative thoughts
• Feeling like everything is going wrong or panicking
• Paranoid thoughts, thinking things are connected or believing things which aren’t real

Some people take ketamine to try and treat long-term mental health issues, even if they don’t consciously realise it. Although taking ketamine can alleviate depression or anxiety for about an hour, it tends to make those feelings worse for the rest of the day. Some people think it is helping, but taking ketamine regularly tends to make people feel more anxious or depressed in the long run.

Depending on your underlying issues, your mental health will often improve after a couple of weeks away from ketamine. It can be hard to access mental health support, particularly if you use drugs regularly. Check out the links at the bottom of this page for support options if this sounds like you.

Falling into a k-hole

A k-hole is a very strong, immersive state of dissociation. Someone in a k‑hole may not be responding to you, and they may make unusual movements or noises, but they are not unconscious in the typical sense.

K-holing in public is pretty inconvenient. It can draw attention to you from security or police, mean you can’t find your way home or leave you vulnerable to being assaulted. It’s easy to think you’re more in control than you really are, then fall over and injure yourself. It is also common for people to fall into waterways and be unable to swim. Some people have died in showers and baths, so avoid these while intoxicated.

If your mate is in a k-hole, make sure to place them in the recovery position (lying on their side). Keep their airways open and monitor their breathing. If they aren’t breathing normally, call an ambulance. A k‑hole usually lasts around an hour before the person gradually comes back.

It is easy to accidentally take too much ketamine. Always make sure you can properly see how much you are about to do, and take a bit less if you are already intoxicated.

Look out for your mates. If you went out together, go home together.

Physical symptoms of ketamine

Using ketamine regularly can affect your body in various ways.

Looking after your nose

Snorting ketamine regularly can give you a sore nose and in the long run damage your nasal structure. Snorting drugs encourages bacteria, which can further erode your nose while you sleep. Ways to reduce the risks to your nose from snorting ketamine include:

• Don’t constantly blow your nose.
• Wash out your nose with a saline spray before bed (sold in any pharmacy). Never use tap water to wash your nose out.
• Crush ketamine crystals into a very fine powder. It should look like flour. Alternatively, cook it up.
• Don’t share snorting equipment. Make your own snortie and keep it to prevent any possibility of catching an infection from someone else.

K cramps

Your nose can only absorb so much at once. If you do a line some of it can drip down your throat and into your stomach. This can lead to two different types of k cramps:

If your lower abdomen hurts, your stomach has become too acidic.

If you have a stabbing pain in your sternum, it is likely your gall bladder. As it stops sending your stomach bile it can build up and harden, causing the biliary duct to expand, which is extremely painful.

If you want to avoid k cramps follow these tips:

• Take smaller lines (so more of it absorbs)
• Spit the drip. There isn’t much bioavailability in the stomach, so anything that has passed your nose is waste.
• Take ketamine less often or take regular breaks.
• Drink plenty of water and keep eating well to help reduce the PH level of your stomach.
• If your stomach feels uncomfortable, stop using before it gets worse.

If you have k cramps, the following things can help manage pain:

• Plenty of water
• Gaviscon or Rennies
• Non oily, spicy or sugary foods e.g. yoghurt or plain bread
• A hot water bottle
• Sitting still or lying down
• If it is your gall bladder (which is to the left of your sternum), try massaging gently to the right of your sternum.

Cramps are a clear sign that you are doing more than your body can tolerate and that you should take a break. Bile flow problems can also cause harm to the liver over time.

Urinary symptoms

Taking ketamine regularly can give you ketamine-induced cystitis. It scrapes away the lining of your urethra, making it painful to pee. Your bladder can also become irritated, meaning you feel more frequent urges to pee when you are on ketamine. If you are experiencing these symptoms, take a break immediately before they get worse. Make sure to drink plenty of water, even though it will make you pee more.

These symptoms will usually clear up with a period away from ketamine. If you struggle to take breaks, see the end of this document for ways to access support. If you often continue to use despite being in pain, there are some supplements which can help a little, but the only way to get better is to take an extended break from using.

Regular ketamine use can affect your kidneys. Upwards pressure from your bladder can make your lower back ache after a binge. If this happens, you should take a break from using. A small number of people have needed surgical procedures on their kidneys, including permanent nephrostomy tubes.

If you ever pass blood or lumps of flesh, stop taking ketamine immediately and go to A&E.

Long-term regular ketamine use can stiffen or scar your bladder, making it less stretchy and reducing its capacity over time. In a small minority of cases this can lead to surgery or removal. Don’t ignore or normalise urinary symptoms – listen to your body and take regular breaks as needed.

Combining ketamine with other drugs

Taking ketamine when you are drunk or stoned can make you feel sick, vomit or pass out, particularly if you don’t use it regularly. Mixing ketamine and alcohol is the number one reason people at festivals end up in welfare. Know your limits and space them out as much as possible.

Some people do ketamine to ease the comedown from other drugs, particularly stimulants. It can enhance the effects of psychedelics or MDMA, but it is important to wait until the effects have mostly passed before taking any ketamine. Be very careful about these combinations in public spaces, e.g. dancefloors. Taking large amounts of ketamine on top of psychedelics can have unexpected effects, and in some instances can lead to psychosis. Start low and go slow.

We don’t have enough evidence yet to know how risky it is to combine ketamine and cocaine, but the mixture is definitely more harmful than taking either drug on its own. It likely adds strain on your heart and may contribute to long term heart issues or overdose risk. If you’re combining ketamine with cocaine, space out them out as much as possible. It is better to let someone recover normally from a k-hole rather than give them cocaine to try and perk them up.

Always keep different drugs on separate surfaces to avoid yourself or others taking something by accident.

Some people use benzodiazepines (eg diazepam or valium) to help them sleep after ketamine. Benzodiazepines have serious physical dependency and overdose risks and are best avoided if you don’t already do them. If you plan on combining benzos with ketamine, make sure the effects of ketamine have completely worn off before using any benzos.

Using ketamine regularly?

Using ketamine regularly can mean you feel like you need it for some social situations, or to just get through the week. Some people continue using despite negative consequences on their mental or physical health, relationships, life opportunities or overall quality of life. Many call this an addiction, but we prefer the term dependency.

Avoid doing ketamine as a response to difficult feelings or because it is part of your normal routine. Recognise your impulses and sit with them rather than responding. Try eating a meal, having a nap, going for a walk and calling a mate before reconsidering your options.

Cravings come in different forms. They might be a quick impulse or a change of plan. Reflect on how your cravings work and ways to manage them.

If you don’t already use ketamine alone, don’t start.

It is important to set abstinence goals that you can realistically achieve, otherwise you will feel bad about yourself. Setting a realistic timeframe is less scary than making a pledge to stop forever. When your period of abstinence is nearly at an end, have a think about whether you want to keep going. Once you have had a period away from drugs, it becomes a lot easier to make bigger commitments.

If you use other drugs regularly but ketamine is your main issue, try cutting them out first. If other drugs act as a trigger to using ketamine they will need to avoided, at least for now.

Make sure people you use with are aware that you are taking a break – this can protect yourself against changing your mind. If you live around ketamine you will need to make some bigger changes (e.g. move out) before having a decent chance of success.

Coming out of a drug dependency is a long process, and success will not be linear. If you lapse, you are not back to square one – you are way ahead of where you were before.

Talking therapy is the best tool you have available to you, so use it! Drug treatment and peer support groups (see links below) are both tried and tested ways to get off drugs, and you have nothing to lose by trying them. If you can afford it and you manage to find someone who suits you, counselling or therapy is also a good option.

Useful Links

Accessing treatment or answering questions

Drugbot

This anonymous Cranstoun chatbot is designed to answer (almost) any question you have about drugs, and is well trained in relation to ketamine. If you tell it you are looking for support for your drug use it can give to contact details for your local treatment service, peer support groups or private counsellors.

Support groups

SMART peer support groups

Online and offline peer-led meetings that use CBT techniques to help you work towards abstinence.

K.W.H.O.L.E.

An online peer-led support group.

Ketamine Anonymous

Online and offline 12-step meetings catered to people who use ketamine.

Author Bio: Dr Josh Torrance

Dr Josh Torrance is an Innovation Officer for Cranstoun. He has worked in drug treatment, harm reduction and drug policy for a decade. He specialises in club drugs, LDIS, NPS, drug education and drug diversion, particularly ketamine. He has a PhD in Criminology and does welfare at events.