The Ultimate Guide to Phenibut

Phenibut is a popular mood-enhancing nootropic that interacts with GABA receptors in the brain to produce anxiolytic effects.

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What you will learn on this page​

  • Definition and chemical make-up 
  • Historical analysis and legality
  • Potential benefits and side effects
  • General safe-usage guidelines

What Is It?

molecular structure of phenibut

β-phenyl-γ-aminobutyric acid (phenibut)

Phenibut is a neuropsychotropic substance that is readily available in powder or pill form by various online vendors and health stores. It is considered to be a nootropic by many but does not have much in common with typical smart drugs such as piracetam.

This is because phenibut is not your typical nootropic compound. It was not synthesized for the sole purpose of enhancing cognitive function. It was originally developed to be used by astronauts in outer-space with the primary objective of reducing feelings of anxiety and stress without compromising mental aptitude.

After its creation and use, the nootropic benefits of the compound were revealed as welcomed secondary effects. Its mechanism of action is actually quite unique when compared to other smart drugs.  Enjoy the video below for a brief analysis of the substance.

How Does It Work?

Phenibut is a derivative of the naturally occurring neurotransmitter GABA, and was first synthesized in the Soviet Union during the 60s.

Unlike GABA, it crosses the blood-brain barrier due to the inclusion of a phenyl ring in the chemical makeup of the compound. Once the compound reaches the brain, it attaches and stimulates the GABA receptors in the brain, acting as an agonist.

Perhaps you recall that alcohol behaves in much the same way. It is generally accepted, however, that phenibut interacts primarily with the GABA-b receptor, whereas the effects of alcohol result from a binding of the GABA-a receptor. In fact, many modern pharmaceutical medications interact with these receptors to treat a variety of ailments.

It is these interactions with the GABA receptors that are responsible for the anxiolytic and tranquilizing effects that are reported from phenibut usage. It can be helpful to visualize phenibut as a key that unlocks ‘pleasure’ sensors in your brain.

General Usage Guide

The outcome of using phenibut, albeit positive or negative, is dependent upon the way in which it is used.  To ensure a beneficial experience, one must understand important details such as how much can be safely used, how long it will take to come into effect and how long the effects might last.  Even though phenibut is generally safe, negative side effects are possible if it is abused.

  • Dosage

Phenibut is very dose sensitive.  Although reports of taking up to 3 grams or more have been reported, the generally accepted phenibut dosage is between 250 and 1000 milligrams per 24 hour period. Any more than this can be considered unsafe.

It is always best to err on the side of caution and begin experimentation with lower dosages before taking more. Spacing two to three smaller doses throughout the day can also be beneficial due to the extended onset and duration of the substance.

  • Onset

Phenibut is a slow-moving substance. Effects can take as long as four hours or more to be noticed by some, while others may notice a difference within the first hour after consumption. Only experience will tell how a particular substance will affect you. Nevertheless, be cognizant of the prolonged onset when planning your day.

  • Duration

The drug has a rather long half life of around 5 hours. Effects can often be felt for two days or more so it is important to space out dose administering appropriately. Tolerance can build quickly if care is not taken in this area.

  • Effects

Many users describe the feeling to being much the same as alcohol in respects to the lowered inhibitions and increases in social comfort, but without the loss of motor control. Not to say that too much Phenybut can’t have negative effects just the same as too much alcohol can, but they are rather different in their effects. 

Many users claim to use phenibut prior to engaging in important social interactions due of their lowered inhibitions and increased fluidity of speech. Reports online of phenibut use before job interviews or first dates is becoming increasingly more frequent. 

  • Contraindications

Phenibut may interact negatively with alcohol, benzodiazepines or other GABAergic substances. Consuming phenibut in combination with other psychoactive drugs is not recommended.  Woman who are pregnant or anyone with predisposed health conditions should always consult a medical professional before ingesting a foreign substance.

Is It Legal?

is phenibut legal to use

Phenibut is mostly legal, but laws change every day. Stay informed or pay the price.

Wondering if phenibut is legal to use where you live?  The answer is predominantly yes; phenibut is an uncontrolled substance and is legal to buy and use in the United States and many other countries around the world.  

However, it is not approved as a dietary supplement, so how it is marketed is important.  To legally sell phenibut, most vendors must declare that it is not intended for human consumption.  In Russia, phenibut is sold as a pharmaceutical drug.

The Psychoactive Substances Act of 2016 makes the legal use of phenibut in the UK a little more unclear. The act generally prohibits substances that produce a psychoactive effect in a person if ,"by stimulating or depressing the person’s central nervous system, it affects the person’s mental functioning or emotional state".​  

This definition is quite vague and is being called a "blanket ban" because it potentially covers a whole gamete of substances.  Phenibut is never specifically noted to be banned and seems to fall in a bit of a grey area as do many other substances.  For those who live in the UK, the best course of action is to use extreme caution and to fully understand the laws before trying to buy phenibut online.  

Common Benefits Of Phenibut

  • Anxiety Relief

Phenibut is often used as an anxiolytic or antidepressant amongst its users. By increasing dopamine levels, it appears that this compound is able to regulate emotional feedback.  This is good news for people with hyperactive neuron connectivity.  Users report that phenibut 'slows down' their minds and helps them to relax.  

  • Sleep Aid

One of the more popular uses of this compound is to assist in healthy sleeping.  Patients with insomnia or general restlessness can benefit from a phenibut dosage prior to bed.

  • Post Workout Recovery

It has also been reported to speed up muscle recuperation after strenuous activities and is often used by bodybuilders to aid post-workout recovery.

  • Enhanced Mood

Perhaps the greatest nootropic quality of phenibut exists within the relaxed state of mind and clear thinking patterns that are inherent for many of its users.  The reported nootropic qualities of the compound include enhanced creativity, some short-term memory increases and increased reaction time.

astronauts use phenibut

Did you know that phenibut has been used by Russian astronauts in space? Pretty Cool!

Possible Side Effects

The side effects of phenibut can be moderate to severe when used irresponsibly. The most common side effects include drowsiness, nausea, dehydration and headaches.  Less frequent side effects include vomiting, dizziness, insomnia, vivid dreams, irritability and blackouts.  Most side-effects are a reaction to taking too much phenibut at one time or over a prolonged period of time.

When proper dosage and frequency is monitored, the side effects should be negligible.  Tolerance and withdrawal are real concerns for frequent users and it is generally recommended to use phenibut sporadically to avoid such unpleasant reactions.

  • Dependency

Tolerance can build in as little as a few days or weeks, depending on the person. It is for this reason that most people find that phenibut is best used for special occasions, perhaps a few times a month during certain events such as presentations or dates.  Daily use is not recommended.  To avoid phenibut dependence, only use it twice a week and take prolonged breaks intermittently.

  • Withdrawal

Prolonged use without proper spacing of doses can bring about withdrawal symptoms that are much the opposite of why one would take this nootropic in the first place. Insomnia, anxiety and irritability are some of the negative effects that can be produced by phenibut withdrawal.  These negative effects can last anywhere from a few days to a few months, depending on the individual situation.

Recreational Use

In the case of any medicinal compound, there are always those that will abuse the recommended usage in order to 'feel a buzz' or 'get high'.  Since phenibut is mostly unregulated, select users have experimented with different ways to use it for recreational purposes.  

Common examples are taking large doses and mixing it with other drugs. These practices are not recommended and are considered unsafe and irresponsible

  • Food For Thought...

Posting personal accounts of misusing phenibut online, could invite regulators to step in and make changes.

Substance Mixing

User reports reveal some people who mix phenibut with alcohol to achieve intoxication quicker.  Phenibut should not be mixed with alcohol due to the risk of negative effects.

Since both drugs stimulate the GABA receptors in our brains, mixing these compounds can cause an amplification of effects. One drink can feel like three, two like five and so on. A few casual drinks while under the influence of phenibut could prove to be quite dangerous for the person involved and is not recommended.


Another trend among abusers of the drug is to take large doses called 'mega doses' in order to achieve sedative-like experiences.  This practice is very irresponsible and dangerous.

This post from bluelight describes people who take upwards of 100 grams in one week!  To put that into perspective, that amount should last a responsible user well over a year.  Abuse at this rate WILL cause side effects and warrants health concerns.

Final Thoughts 

Originally developed for Russian cosmonauts, phenibut can be a useful nootropic, mood enhancer and sedative when used responsibly. Improper use can lead to nasty side effects and unpleasant withdrawal symptoms.


  • Anxiety Relief
  • Sleep Aid 
  • Increased Sociabilty
  • Mood Enhancement


  • Risk of Dependency
  • Withdrawal Symptoms
  • Dose Sensitivity 

Over the course of 5 decades more than 300 research papers have been written about the positive and negative effects of this drug.  At current, it is unregulated in most countries around the world and is readily available online.

Nicole Sanders

Hi, I'm Nicole, chief editor at Nootropics Revealed. Learn more about me and my mission here.