4-FA / 4-FMP

What is 4-FA or 4-FMP?

4-FA (4-fluoramphetamine) is an amphetamine-like drug that has only appeared on the Dutch market for a relatively short time. In the period from 2007 to 2009 it was mainly sold as speed or MDMA. This was because at the time there was a shortage of raw materials for these agents, so 4-FA was used as a cutting agent. However, since 2010, 4-FA has been increasingly sold as 4-FA by dealers, which also means that consumers see it as a “drug of choice”.

Other names for 4-FA include: 4-FMP, 4-Fluor, 4-Flava, 4-F or Flux. It is a substance that falls under the new psychoactive substances (NPS). These are substances that have only recently been on the market and have been developed as an alternative to conventional illegal substances. NPS are also known as research chemicals or designer drugs. By changing something small to an existing chemical structure, the substance name changes and is therefore no longer covered by the Opium Act and thus illegal. This makes it more difficult to prevent production, sales and ownership.

How do you use 4-FA or 4-FMP?

4-FA is most commonly found in the form of powder or pills. In pill form 4-FA is taken orally. Users put powder in a capsule or a rolling paper (bomb) or are sometimes dissolved in a drink. There is no difference in effect between 4-FA pills, 4-FA powders or capsules with 4-FA.

Capsules are made from a starchy or sugary substance and can be transparent or have different colours. A capsule can be filled with all kinds of substances. 4-FA, but also other substances such as amphetamine (speed), MDMA, caffeine or nothing at all. Some smart shop products are also in capsules. The capsules are usually in a bag and the bag then says what’s in it. If users fill a capsule themselves, they can use a mg scale to determine an accurate dose.

What are the effects of 4-FA or 4-FMP?

What someone feels after taking 4-FA initially depends on the dosage. To find out, 4-FA can be tested at a test service (see menu). After swallowing 4-FA, it takes around 20 to 60 minutes for the effects to occur. The 4-FA is finished after 4 to 8 hours, although some users report that the after-effects can last up to more than 12 hours.

Psychic effects

  • Energetic, clear, fit and alert
  • Light euphoria, cheerful and cheerful
  • Strong sense of belonging
  • Intense experience of touch and music
  • Strong need for contact, talking and intimacy
  • Confusion and anxiety may occur at high doses

Physical effects

  • Increase heart rate / blood pressure and body temperature
  • Sometimes nausea
  • Decreased appetite
  • Increasing pupils
  • Tense muscles
  • Stiff / tense jaws, gnash teeth
  • Dry mouth / feeling thirsty
  • Trouble urinating
  • Increased endurance so that you can dance for hours
  • Sometimes sweating, nausea, vomiting, headache, dizziness
  • Difficulty sleeping

Absorption, effects and breakdown of 4-FA or 4-FMP


4-FA is usually swallowed. The stomach acid dissolves the 4-FA, which releases the active substances. The 4-FA is processed with the rest of the stomach contents and reaches the small intestine. The 4-FA is absorbed into the blood there. After the small intestine, the blood (via the portal vein) first goes to the liver. A part of the 4-FA is broken down by enzymes there.

The blood then goes to the heart with the remaining 4-FA. The heart pumps the blood to the lungs (to absorb oxygen).

The heart then pumps the blood to the rest of the body and to the brain and organs including the liver and kidneys. The brain provides the effects, the liver and kidneys for the degradation and excretion.

When sniffing, the 4-FA is absorbed directly into the blood via the nasal mucosa, so the effect is also felt faster.

The heart then pumps the blood to the rest of the body and to all organs, including the brain, liver and kidneys. These organs take care of the effects, the breakdown and the excretion.

Effects of 4-FA / 4-FMP in the brain

Part of the 4-FA-rich blood arrives in the brain. In the brain, 4-FA influences the way in which nerves transmit signals to each other. Nerves do that with the help of certain substances. These substances are called neurotransmitters or transfer agents. 4-FA influences the functioning of the neurotransmitters noradrenaline, serotonin and dopamine.


The 4-FA-rich blood also arrives in the liver. The 4-FA is further broken down in the liver. In the end the blood arrives in the kidneys. The kidneys filter 4-FA and the breakdown substances from the blood, after which they are excreted in the urine.

What are the risks of 4-FA or 4-FMP?

Analysis show that a significant increase in the number of health incidents can be observed through the use of 4-FA. The incidents caused from minor symptoms such as headaches to brain bleeding and problems with the heart. A few cases are also known of people who died after the use of (presumably) 4-FA, but further investigation is needed to provide a definitive answer.

An important danger with the use is that the complaints that users experience at first are fairly mild in nature, in particular (mild) headaches and (mildly) treated blood pressure. Complaints can unexpectedly turn into life-threatening situations, such as cerebral haemorrhage. Users of 4-FA who experience complaints as a headache after use are advised to go directly to the first aid of an event of the doctor.

Short-term risks

There are the following short-term risks with 4-FA:

  • Severe headache
  • Overheating (hyperthermia)
  • Cardiac arrhythmias, respiratory problems and increased blood pressure
  • Damage to the teeth
  • Bad trip and psychological complaints

Severe headache

Users can get severe headaches during and after 4-FA use.

Overheating (hyperthermia)

The body temperature rises through the use of 4-FA (similar to amphetamine). When 4-FA, as with XTC from amphetamine, is used in a warm, busy environment, the body temperature rises even further. If someone is also dancing hard for a long time, overheating can occur.

Symptoms of incipient overheating:

  • Headache
  • Confusion
  • Stiff muscles
  • Dizziness

These are all symptoms that can also fall under the normal circumstances of 4-FA. If the body temperature does not drop, the following symptoms may occur:

  • Shivering
  • Fast heartbeat
  • Pale appearance
  • Decreased consciousness
  • Nausea
  • Vomit

If the body temperature rises to 40-41 degrees Celsius, the situation is life-threatening:

  • Breakdown of muscle tissue
  • Blood clotting throughout the body
  • Deteriorated played of kidneys and liver
  • Epileptic attacks

Depending on the circumstances, overheating can occur at “normal” doses of 4-fluoramphetamine. Overheating is very dangerous and difficult to treat. Seeking cooling, taking a rest and drinking enough water (maximum 1 glass per hour) is necessary to prevent overheating. Sweating is also an important way to cool down: by evaporating the layer of sweat on your skin, your skin cools down. But if the humidity is very high (when the drops fall from the ceiling), the sweat can evaporate less well and your body cannot cool down properly.

Cardiac arrhythmias, respiratory problems and increased blood pressure

At high doses there is a risk of cardiac arrhythmias such as a dangerously high heart rate (tachycardia). There are also cases with respiratory disorders (hyperventilation) and dangerously high blood pressure (1). The latter risk is increased when 4-FA is combined with anti-allergy pills (e.g. against hay fever).

Damage to the teeth

By 4-FA you can go grinding teeth. That can be harmful to your teeth. You also make less saliva. Saliva is the natural cleanser of your teeth.

Bad trip and psychological complaints

Anxiety during 4-FA use can occur. This can also be called a “bad trip”. Panic attacks that sometimes persist for some time after 4-FA use can also occur. Some users may experience depression. The more often and more is used, the greater the chance that someone will feel depressed in the longer term. This is mainly because then the release and re-uptake of the substance serotonin is disturbed. In addition, there are complaints such as feelings of anxiety, reduced concentration, fatigue, headache, tingling, muscle twitching, vision problems and dizziness.

Source: 1: CAM Quick Scan rapportage van 4-fluoramfetamine (4-FA), RIVM 2016

Long term risks

4-FA has not been used for that long, so the long-term risks are not yet known. This simply cannot be investigated yet. The long-term risks are probably comparable to other uppers such as XTC, cocaine and speed.

4-FA or 4-FMP and the law

In the Netherlands, 4-FA was subject to the Opium Act until 25 May 2017. If someone was caught by security or police, you were therefore not legally punishable.

As of May 25th , 2017, 4-FA will be on list I of the Opium Act and possession and trade is illegal and thus punishable.

4-FA or 4-FMP and traffic

Someone who uses 4-FA can be reckless and confident, but also irritable or aggressive. In addition, 4-FA also disrupts coordination. Participation in traffic under the influence of 4-FA is therefore risky. When the 4-FA works off someone is exhausted. This is of course also very dangerous in traffic. As with almost all psychoactive drugs, participation in traffic under the influence of 4-FA is prohibited by law and can lead to high fines or a driving ban.


Versie: april 2020