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Why Is Phenibut Sometimes Consumed as a Nootropic?

Phenibut is a synthetic drug used both medically and recreationally as a nootropic. With both calming and cognitive-enhancing effects, phenibut could have many useful benefits, even including aiding astronauts on space missions.

This article explores some of the neuroscience of phenibut and the evidence investigating its potential benefits on cognitive and mental health.

What Is Phenibut?

Phenibut is a synthetic molecule first synthesized in the 1960s by a group of organic chemists in Russia.

Soon after its synthesis, scientists began experimenting with the drug medically, showing it to be an effective tranquilizer with anti-anxiety properties and uplifting effects on mood and cognition. These effects quickly gained phenibut widespread use in Russia.

In the late 1970s, phenibut was even included in the cosmonauts’ kits to help aid their sleep and thinking capabilities while in space.


To date, doctors in Russia still prescribe phenibut for various medical purposes, including tension relief, anxiety, sleep improvement, and as pre-and post-operative medication.

Phenibut is currently legal in the USA and UK, sold as a dietary supplement. However, concerns about its addictive qualities and withdrawal effects mean it hasn’t gained approval by the FDA as a licensed drug.

Phenibut is considered a nootropic drug because of its ability to increase cognitive functions, such as memory and attention.

Brand names of phenibut include Noofen, Anvifen, and Fenibut.

Phenibut Uses

Here’s some of the evidence supporting the different health benefits of phenibut.

Reducing Anxiety

In one study, scientists compared the effects of phenibut with adaptol- a standard anti-anxiety medication, on patients with co-morbid anxiety and cerebral ischemia. Both drugs had similar effectiveness in treating anxiety and took an equivalent length of time to achieve their effects. Phenibut also improved the patients’ sleep disorders and tiredness, as well as anxiety.

Although this evidence indicates phenibut may be helpful in anxiety, it’s important to consider the study only looked at phenibut effects on a relatively small number of patients (29).

Research has shown that phenibut improved patients’ sleep disorders and tiredness, as well as anxiety.

Another study investigated the effect of phenibut on anxiety behavior in animals. In this study, researchers showed that when animals were exposed to negative emotional situations, they showed anxious behavior associated with increased activity in a brain area called the hippocampus. However, phenibut injection before exposure decreased these effects.

Some scientists have suggested that in humans, hippocampus overactivity could also be linked with anxiety disorder. Decreasing hippocampus activity could therefore explain an anti-anxiety mechanism of phenibut.

Cognitive Enhancement

An experiment investigating the effects of phenibut on cognitive impairment gave 62 patients with cognitive impairment relating to anxiety disorders 1000mg phenibut per day. At the end of the study, around 73% of patients showed improvements in attention, memory, levels of emotional intelligence, and improvements in anxiety.

Animal studies show that phenibut can decrease animals’ time to learn a response, demonstrating how phenibut may be useful for learning and memory formations.

Reductions in Chronic Fatigue

In one study, researchers looked at the effects of phenibut on a group of patients with chronic fatigue. The study participants either continued to take their standard treatment or standard treatment alongside phenibut. In around 75% of the phenibut group, physical and mental fatigue decreased by 30-50%. The phenibut group also showed an improvement in motivation.

Sleep Improvement

A group of scientists showed phenibut was able to improve sleep quality in patients suffering from alcohol withdrawal. However, the experiment only considered two nights of sleep, so this evidence is relatively unreliable.

Improvements in Symptoms of ADHD

Children with attention deficit hyperactivity disorder (ADHD) took either phenibut or low doses of multivitamins (control) for one month. Compared to the multivitamin group, children who took phenibut had improved cognitive functions, including improved self-control, improved attention, and improved acoustic and verbal memory at the end of the month.

Although this evidence suggests phenibut may be helpful in ADHD, it’s important to note the study took place over a relatively short time so it doesn’t account for long-term effects.

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Phenibut Effects on the Brain

Phenibut affects the brain by acting on specific neurotransmitters, chemical messengers that send signals across different parts of the brain. We’ve highlighted these neurotransmitters below.


Scientists have shown that phenibut mimics the effects of a neurotransmitter called GABA by activating GABA(A) and GABA(B) type receptors.

As GABA has an inhibitory function, phenibut can slow down activity in the brain, explaining why it has a calming effect and can be helpful in treating anxiety and insomnia.


Scientists have shown phenibut may increase the function of a neurotransmitter called dopamine by increasing the rate it’s used up and recycled in the brain.

This effect could help explain the nootropic effects of phenibut since dopamine is associated with both memory and attention. Dopamine is also involved in reward and pleasure, accounting for some of phenibut’s euphoric effects.


To show the effects of phenibut on dopamine, scientists investigated whether phenibut was useful in treating Parkinson’s Disease (PD), a disorder caused by a loss of dopamine-producing cells. The scientists showed that giving phenibut to PD patients alongside their standard treatment was more effective in improving symptoms than standard treatment alone.

Phenethylamine (PEA)

Another effect of phenibut is stopping the action of a neurotransmitter called phenethylamine (PEA). Studies have shown that PEA can cause anxiety in mice, so phenibut’s action on PEA may also explain why it’s helpful in anxiety treatment.

Phenibut Dosage

In clinical research, people typically take between 0.25 to 1g of phenibut per day, spread between two separate doses. Like all drugs, suitable doses typically depend on the height, weight, and health of users.

Taking other depressant drugs, such as alcohol or benzodiazepines, alongside phenibut will increase the risk of overdosing.

Because of its depressant effects on the nervous system, phenibut overdose could cause a shut down of the respiratory system, resulting in coma and even death. Taking other depressant drugs, such as alcohol or benzodiazepines, alongside phenibut will increase this risk.

As with all drugs, new users should always start with small doses and take only with the supervision of a physician.

Phenibut Side Effects

Some of the negative side effects associated with phenibut include:

  • Headache
  • Loss of motor coordination
  • Nausea and vomiting
  • Insomnia
  • Allergic reactions – such as skin rash or itching

Tolerance and Withdrawal

Regular use of phenibut can easily lead to tolerance, meaning people need to take higher doses to achieve the same effect. These higher doses increase the risk of harmful side effects.

Because of tolerance, it’s recommended people don’t take phenibut more than three times a week.

When people stop regularly using phenibut, this can cause side effects linked to withdrawal. These include:

  • Anxiety
  • Agitation
  • Depression
  • Cognitive deficits
  • Fatigue
  • Dizziness
  • Palpitations
  • Insomnia
  • Nausea and vomiting
  • Tremor

Withdrawal symptoms can lead to addiction, where users keep taking phenibut to avoid these adverse side effects.

Liver Toxicity

Although no formal case studies have been published, anecdotal reports from phenibut users have reported symptoms of liver damage. Signs of liver damage include:

  • Dark urine
  • Circulation problems
  • Swollen abdomen
  • Stomach pains
  • Drowsiness

Final Thoughts on Phenibut

Although limited, research suggests phenibut could have several positive effects. However, because people can easily build tolerance and develop withdrawal symptoms, phenibut has a relatively high risk for addiction – which could cause more harm than good.

If you’re considering taking phenibut, it’s well worth consulting with a medical professional first to assess the safety and other available options.

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