4-MMC / mephedrone

What is mephedrone or 4-MMC?

Mephedrone or 4-MMC (4-methylmethcathinone) belongs to the class of synthetic cathinones, a subgroup of amphetamines. Mephedrone is also called meow meow (meow meow), MCAT or bubble. It mainly occurs as a white crystal or powder, but is also available in capsules. It is very similar to its brother 3-MMC, but is often experienced as more euphoric by users.

Mephedrone is a so-called New Psychoactive Substance (NPS) or research chemical. NPS are rarely well researched. Very little or nothing is known about the short and long-term risks, consequences of frequent use and the risk of addiction. Little is also known about the optimal dose and which dose poses a risk.

Always be extra careful with new drugs. This applies even more to resources that fall into the category NPS: You are your own guinea pig. If you don’t want to take a risk, don’t use drugs.


Mephedrone is a stimulant.

The effect of a substance is determined by the properties of the substance itself, but also by the set and setting of the user. Here we describe what effects mephedrone generally has.

Mephedrone puts the user in a state of euphoria, which is somewhat comparable to ecstasy/MDMA, but is milder in terms of empathogenic (being able to empathize with the other person) and entactogenic (feeling of belonging) effects. The effect of mephedrone is often described as a combination of MDMA and cocaine. The user feels energized, stimulated and tends to talk a lot.

Particularly with high doses and long-term use, negative effects can occur. User reports range from palpitations to paranoia and purple discoloration of limbs. Other reported side effects include nausea, headache, dizziness, excessive sweating, heart pain, nosebleeds (when snorting), and feelings of anxiety.

Positive effecten (negative) Side effects

Euphoria, feelings of love

This substance can make you feel euphoric, like you are in love. You feel comfortable in your own skin and can experience things as pleasant more quickly.

Increase in blood pressure and heart rate

Due to increased cardiac stimulation, heart rate and blood pressure rise.

Need for contact, conversation and intimacy

Having a good conversation with someone, or cuddling, can be very pleasant and interesting.

Increased body temperature

Stimulants cause increased activity in muscles, and increase the “base temperature” of the body. This causes the body temperature to increase.

Energetic feeling

You have feelings of being energized. Sitting still is sometimes more difficult and this energetic feeling is often expressed through the urge to dance or move.

Jaw clenching

Increased muscle tension can cause the jaws to clench together. As a result, the teeth are firmly pressed together and it is possible to bite your tongue and/or cheeks.

Enhanced sensory perception

All sensory experiences that you normally have such as feeling, smelling and tasting become stronger. For example, a nice drink can taste much tastier. Music seems to have gained an extra dimension. It is also possible that some senses become a bit oversensitive and that you find things too intense, such as the lights on the dance floor. So this can be positive or negative.


Feeling a (strong) need to take more when the effect wears off.

More intense music experiences

Music can be experienced louder or more intense. For example, it can feel as if you are completely ‘absorbed’ in the music or that you feel the low tones from the music go through your body more intensely.


This substance leads to an increase in impulsive behaviour and can make you less aware of the possible consequences that certain actions have. This can be nice because, for example, it is easier to approach someone and have a chat. However, it can also lead to negative situations as you can get into an argument or physical altercation more quickly.

More intense experience of touch

Physical/physical contact with other people feels different or more intense than usual. Giving a hug to someone else can be very pleasant. It can also happen that you prefer not to touch others because this can be too intense. This effect can therefore be both positive and negative.

Confusion and restlessness

Confusion and restlessness

Increased libido

Increased sexual desires. You feel more attracted to others and feel a stronger need for sexual intimacy.

Paranoia and delusions

Anxiety, paranoia and delusions (e.g. the idea that people are talking about you).

(Nederlands) Verandering in tijdsperceptie

The passage of time could feel altered during drug use. Some parts of the evening fly by, while some parts feel a lot slower. When you are feeling comfortable, it can be nice that the feeling does not seem to stop. But if you feel uncomfortable, this can be a bothersome experience. So this effect can work both ways.


Easily annoyed or irritated.


This drug can make you more active than usual. You are feeling sharp, awkae and it is easy to focus your attention on the things that are happening around you.

Decreased ability to concentrate

Decreased ability to concentrate.

Accelerated thoughts

Thinking seems to go faster. It’s also easier to think clearly. You can go through certain steps in your head faster and make choices faster.

Impaired short-term memory

Short-term memory does not work properly after taking some drugs. This makes you remember things less well. For example, it often happens that during a conversation you forget what you were talking about, or that you forget the reason you walked somewhere. The next day you often don’t know very well what happened the night before.

Head ache

Head ache


An uneasy and tense feeling in the abdomen, which may cause discomfort. Nausea often precedes vomiting.


Some drugs keep you from falling asleep. Stimulants often have this effect, but even after using psychedelics or downers, sleep is disrupted and it is possible that you can’t sleep.

Decreased appetite

Stimulation of the fight-or-flight response in the body can suppress appetite.

Increased sweating

In response to the increased stimulation and changes in body temperature, the skin will start to secrete sweat to cool the body temperature back to normal levels.

Dry mouth

Stimulation of sympathetic pathways decrease saliva production, this causes the mouth to feel dry.

Dilated pupils

Due to an increased noradrenaline level in the body after taking certain drugs, the pupils become larger. The pupil size is influenced by many different processes. Increase in noradrenaline plays a role in some of those processes.

Double vision

Not being able to focus your eyes properly.

Difficulty urinating

Your body releases a lot of antidiuretic hormone (ADH) causing you to retain more fluids. There is also more tension in the muscles in your urinary tract, which makes relaxing (and therefore urinating) more difficult.

Blue limbs

The discoloration is due to the narrowing of the blood vessels.

Dose and route of administration

Mephedrone can be both swallowed and snorted. When used orally (swallowing), this can be done by means of a ‘bomb’ (a dose in a paper roll, after which it is swallowed), a capsule or pill. The chance of dependence and the strong urge to take more is smaller with oral use than with snorting the mephedrone. Mephedrone can also be injected, but this hardly happens in the Netherlands.

Doses for swallowing
Low 25 – 75 mg
Medium 75 – 150 mg
High 150+ mg
Doses for snorting
Low 15 – 25 mg
Medium 25 – 75 mg
High 75+ mg

To know whether your mephedrone actually contains what it is supposed to, you can have your drugs tested in the Netherlands.


The duration for oral use (swallowing) is between 1.5-3 hours. With nasal use (snorting) this is 45 minutes to 1.5 hours. This is followed by a period of a few hours in which it is difficult to go to sleep for many people, but the desired effects are no longer felt. Many people experience a dip and a strong urge to take more during this period, similar to cocaine.


Mephedrone is a so-called new psychoactive substance (NPS) or research chemical. NPS are rarely well researched. Very little or nothing is known about the short and long-term risks, consequences of frequent use and the risk of addiction. Little is also known about the optimal dose and which dose poses a risk. The risks are expected to be in line with those of other stimulants, such as speed, cocaine and MDMA.

Mephedrone speeds up the heart rate and raises blood pressure. People with high blood pressure and/or heart problems are advised not to experiment with stimulants. People who develop purple limbs after using mephedrone are also advised not to use it. There is some evidence that mephedrone may cause problems with the autoimmune (defense) system (vasculitis) in a small percentage of people.

Users report that taking mephedrone can lead to cravings (a strong need to take more). These cravings often occur earlier when snorting than when taking mephedrone.

Always be extra careful when trying out new drugs. This applies even more to resources that fall into the category NPS: You are your own guinea pig. If you don’t want to take a risk, don’t use drugs.

Short term risks

(Nederlands) Triggeren (drugs-) psychose

Sorry, this entry is only available in Nederlands.

(Excitement) delirium

This is a state of being that is usually caused by excessive alcohol or drug use. Often, it involves stimulants such as cocaine. The acute state of excitement is a life-threatening situation that requires prompt intervention by professional caregivers. You can recognize it because someone behaves very agitated and aggressive motorically. The victim lashes out and cannot be calmed down. The aggression is not directed, but rather random. It is impossible to make contact with the victim. The victim continues to fight, even when subdued by police and security.

Because someone behaves this way, it is understandable that security or caregivers may want to subdue them by pushing them down or restraining them (fixation). However, this is dangerous and can lead to death. When you try to stop someone with an excitement delirium, the person will only resist harder, causing their heart rate/blood pressure to dangerously increase.

Vasoconstriction (blood vessels narrowing)

Stimulation of the sympathetic (fight-or-flight response) nerve pathways causes the blood vessels around some organs to contract and narrow, redirecting the relative blood flow to the muscles to increase.


Epileptic seizure

Taking this drug increases the risk of having an epileptic seizure if you are prone to it.


Stimulants increase your body temperature. Additionally, more physical activity also raises your body temperature. If this happens in an environment that is already warm, where you cannot dissipate heat effectively, it can become dangerous.

Because your body loses heat through sweating, this risk mainly occurs in warm and humid environments. If the air is very humid (muggy or clammy), the cooling effect of sweat is reduced. This can cause your body to overheat. Additionally, you lose a lot of body heat through your head. Avoid wearing a hat or cap when it’s warm so that heat can escape.

Some drugs, especially those that cause a significant release of serotonin, can lead to mild overheating with “normal” use.

Symptoms of mild overheating (hyperthermia):

  • Headache
  • Confusion
  • Stiff muscles
  • Dizziness

In this case, seek a cool place and consider wetting your head, neck, and face with water. If you then blow air over these well-vascularized areas of your body with a fan (or ask a friend to do so), you can quickly cool down to a more comfortable temperature.

Symptoms of more severe overheating (hyperthermia):

  • Shivering Rapid heartbeat
  • Pale appearance
  • Reduced consciousness
  • Nausea Vomiting

When experiencing these symptoms, it’s time to seek help from a first aid post or other healthcare provider. If the body temperature rises to 40-41 degrees Celsius, the situation is life-threatening. It’s important to quickly move to a cooler place.

Very severe symptoms:

  • Breakdown of muscle tissue
  • Blood clotting throughout the body
  • Impaired functioning of kidneys and liver
  • Epileptic seizures

Call 112 immediately if you notice or experience these symptoms.

Over-fatigue and insomnia

Under the influence of (stimulating) substances, you can exceed your own limits and boundaries, because it suppresses your fatigue and sleep. You then tap into your reserves and can be over-fatigued and downcast days after use. The longer and more you have used, the longer these feelings can persist.


(Tuesday) dip

After using this drug, a dip can occur. You feel tired, depressed, sad, listless, oversensitive, and empty. The severity of the dip varies greatly from person to person. However, users often report experiencing fatigue and a bad mood in the days after use. It is unclear what exactly causes the dip with a drug. But a high dose, combined use, dancing combined with little food and little or no sleep certainly play a significant role.

Long term risks

Increased risk of arrhythmia, heart attack, and stroke

Stimulants increase your bodily functions.

Among other things, your heart rate increases and your blood pressure rises.

People with high blood pressure and/or heart problems are advised against experimenting with stimulants.

Cocaine has more negative effects on the heart than other stimulants.

Problems with the immune system

There is some evidence that this drug may cause problems with the autoimmune (defense) system in a small percentage of people. This is an inflammatory process of the blood vessels that often leads to closure of the vessels. This is called vasculitis.

Psychological issues

Psychological issues can arise, or pre-existing psychological problems can worsen. Feeling down or anxious, feeling out of sorts, and experiencing poor concentration.

Psychological addiction

Psychological addiction means that you feel like you can’t live without a substance.

You can however stop taking this drug, without your body experiencing any issues.


Combining different types of drugs can be risky and unpredictable. When you combine drugs you can have a higher risk of health problems. In the following paragraphs you can read about the effects and the risks of a number of combinations that occur frequently and also a about few that are extra hazardous. Also check our theme combining drugs.

4-MMC and alcohol

4-MMC give you energy and makes you less tired. As a result, you may feel the sedating effects of the alcohol less and you may tend to drink more alcohol. Be careful, because this can cause an extra large hangover. So do not drink alcohol while taking 4-MMC use or make an agreement in advance with yourself or your friends how many glasses of alcohol you want to drink. This prevents headaches the next day and is better for your health!

4-MMC and cannabis

Some users find it a pleasant combination. Cannabis can soften the rush, especially at the end. However, it can also make the experience a bit more vague, which is not always positive.

4-MMC and GHB

4-MMC is sometimes combined with GHB to take the edge off the 4-MMC or to make you hornier when used in a sexual setting. The risk of the combination is that you will not feel the anesthetic effect of GHB due to the stimulating effect of 4-MMC, which increases the chance of overdosing with GHB. If you then take too much GHB, your body is still stimulated, but you are no longer or not fully conscious. That can look very weird. Someone then moves very strangely but it is not possible to make (proper) contact.
Here you can read more about what to do when somebody passes out.

Unity tips

Very little is known about the risks of mephedrone, and there is no real safe use of drugs. The risks can be limited, read the Unity tips for this:

  • Only use if you feel good mentally and physically.
  • Rest well before and after mephedrone use.
  • Eat healthy before and after mephedrone use. Especially a lot of reserve substances (nuts, peanuts) and vitamins (oranges, kiwi, broccoli).
  • It is difficult to eat during and after mephedrone use, but try to eat something salty (chips). Eating definitely reduces the hangover! If you don’t eat solid foods, think juices, breakfast drinks and smoothies.
  • Drink a maximum of 1-2 glasses of water or a soft drink every hour to prevent dehydration and overheating, but prevent water intoxication.
  • Make sure you don’t get too hot while using mephedrone: rest occasionally, don’t wear warm clothes, no headgear, and drink water or soft drinks every now and then.
  • You can use extra vitamins and antioxidants before and after mephedrone use.
  • Do not use if you have any of these conditions: diabetes, weak heart, high blood pressure, pregnancy, epilepsy and psychological complaints or in combination with medicines (especially not with MAO inhibitors and asthma medicines).
  • Do not combine with alcohol, other drugs, or medicines
  • Do not participate in traffic.

Unity tips for using stimulants

  • Do not combine high stimulant doses with other stimulants
  • Do not use stimulants if you suffer from diabetes, cardiovascular disease, epilepsy or psychological afflictions. Also, do not use stimulants if you are pregnant, or in combination with medications (especially MAO inhibitors and asthma medication).
  • Make sure you don’t get too warm while using stimulants: rest every now and then, don’t wear (too) warm clothes or headgear and drink water/soft drinks occasionally.
  • Get enough rest before using stimulants. If you are very tired or suffer from insomnia, do not use stimulants!
  • Moderate use is key. Keep track of how much you take.
  • Drink enough to keep yourself hydrated, but no more than 2 glasses of water per hour. Exceeding this increases the risk of water intoxication.
  • Stimulants can give you a dry mouth, which, combined with teeth grinding, increases the risk of damage to your teeth. It is important to stimulate your saliva production. You can do this by chewing sugar-free gum. Saliva substitutes or artificial saliva (such as Saliva Orthana, Xialine and Oral Balance) can also be used and can be purchased without a prescription.

Unity tips for using drugs

  • When using a drug for the first time, take only a small dose to see how your body reacts to the substance
  • Only use drugs when you are feeling well
  • Use drugs recreationally, not to combat psychological issues like fatigue
  • Avoid using drugs if you have (had) psychological afflictions or if you have a family history of psychological diseases (such as depression) in your family
  • Test your drugs before use at a drugs-testing service
  • Make sure to prepare a good set and setting for drug use
  • Only use drugs sparingly. Keep track of your use over time.
  • Decide in advance how much you are planning to use over the evening, and stick to that. 
  • Do not combine drugs with other substances or medicines
  • Do not participate in traffic after drug use
  • Prevent infectious diseases; Use your own snorter/sniffer and do not share paraphernalia with others
  • After insufflating, rinse your nose well with lukewarm saline water (for example, by using a nasal spray or nasal douche)
  • Are you, or one of your friends not feeling well? Keep an eye out for one another, take care of each other and visit the first aid (if one is available)
  • Call 112 in a life-threatening situation
  • Eat healthy before and after drug use. In particular, foods with lots of antioxidants and vitamins (blueberries, raspberries, blackberries, grapes, raisins, oranges, kiwi, broccoli). This is perhaps the most important tip! It can be difficult to eat during and after drug use, but make sure to try to eat something anyway. Eating well is a great way to reduce the hangover! If you can’t hold in solid foods, try juices, breakfast drinks, and smoothies.


How do you dose powder or capsules?

To be able to weigh a certain dose properly, you need a good scale. Have a scale that can weigh milligrams, to 3 decimal places (0.001 mg). A scale that weighs 0.01 (2 decimal places) may be just accurate enough for MDMA, but not for many other substances.

Where can you find such a scale?

On the large international online webshops you can find scales for around 20 euros that can weigh 3 figures after the decimal point. You can buy empty capsules in different sizes at pharmacies, smart shops or drugstores. Some are also suitable for vegetarians. You can write the drug and dosage on the capsule with a waterproof marker or a CD marker.

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