Issac Thorne

Last Updated February 12, 2022

Looking for information about the phenibut withdrawal process? Then this article is for you.

More and more nootropic researchers are studying the powerful effects of phenibut. These are believed to include reduced anxiety, more sociability, better sleep, and elevated mood.

But there are also some reported cases of phenibut dependence and addiction. Some individuals may experience withdrawal effects when they stop taking phenibut.

Phenibut addiction and withdrawal is a concern that warrants consideration by all phenibut researchers.

We've gone deep into the research literature to find out what you need to know about phenibut withdrawal. Let’s get to it.

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What is Phenibut?

Phenibut is a neuropsychotropic drug that is chemically similar to GABA (gamma-Aminobutyric acid), a chemical that we make naturally in our brain [1].

Before we can begin to understand how an individual can become dependent on this drug, we’ll need to discuss how GABA works in the nervous system.

Understanding neurotransmitters

First, a refresher on the nervous system.

The nervous system is like the control center of the body. It includes the brain and spinal cord as well as all the nerves that run throughout the body. It is responsible for receiving information from sensors around the body, sending that information to the brain to process, and then sending signals back to the body to coordinate a response.

How does it send those signals? Through nerve cells called neurons. Those neurons communicate with each other using neurotransmitters. One neuron releases neurotransmitters that communicate with specific receptors on the next neuron. Neurotransmitters are essential for successful communication between neuron cells.

Phenibut mimics GABA

GABA is a neurotransmitter that inhibits action. Due to its structure, phenibut mimics GABA and binds to GABA receptors. Phenibut primarily binds to the GABAB receptors, which create slow-acting inhibitory signals in the body. It also binds to GABAA receptors at high concentrations, which switch on fast-acting inhibitory signals [1].

Because phenibut binds to the GABA receptors, it has GABA-like effects. For example, phenibut appears to produce a calming effect in people with anxiety disorders, making them feel less stressed and getting them ready for sleep. Due to its anxiolytic effects, phenibut is often prescribed in countries like Russia to reduce anxiety and improve sleep [1].

At low levels, phenibut also results in the upregulation of dopamine, another neurotransmitter that is associated with the pleasure center of the brain. Dopamine is likely responsible for the “high” or euphoric feeling that some phenibut users report feeling from the drug.

Phenibut has been a prescription drug in Russia and other countries of the former USSR since the 1960s when it was discovered [1]. In the United States, phenibut has not been reviewed or approved for any use. It has the status of a “New Drug” under the U.S. Federal Food, Drug, and Cosmetic Act (FD&C Act). It’s available for research purposes, but not for general consumption or for use as a medication.


Phenibut Side Effects and Safety

Phenibut is generally considered well-tolerated. One review of clinical phenibut research concludes that “the acute toxicity of PB is low [1].”

However, phenibut does have side effects and safety issues [2]. Anyone conducting phenibut research on human participants should keep these in mind when defining studies and dosing protocols.

Potential side effects include [2, 3, 4]:

  • Irritability
  • Drowsiness
  • Sedation
  • Nausea
  • Headache
  • Hangover-like symptoms
  • Motor incoordination

Phenibut can also produce an allergic reaction [3]. Common allergic reactions to phenibut include itching and rashes on the skin.

To avoid adverse effects, test subjects should be counseled on the appropriate phenibut dosing. See the dosing guide for more information about phenibut dosage.

Interaction effects

As a depressant, phenibut slows down the nervous system. It is important not to combine phenibut with other medications or substances that are also depressants. The combination of depressants could have stronger, longer-lasting, and sometimes even dangerous effects.

Substances that should not be mixed with phenibut include [3]:

  • Alcohol
  • Benzodiazepines
  • Anticonvulsant medications
  • Antipsychotic medications
  • Opioids
  • Sedatives
  • Anti-anxiety medications


Phenibut overdose can result in a host of severe symptoms and consequences, including death.

Manufacturers of phenibut list the maximum single dose (when it’s used as a prescription medication) as 750 mg, noting 2.5 g as the maximum daily dose [3]. A prudent dose for research purposes could thus fall between 250 mg and 500 mg in one day.

Ingesting phenibut in excess of the recommended dose can result in the following overdose symptoms [3, 6]:

  • Severe drowsiness
  • Nausea
  • Vomiting
  • Lowered blood pressure
  • Psychosis

In the United States, there has been at least one death reported from a phenibut-only exposure. While we are not aware how much phenibut the deceased had ingested in that case, it does show that phenibut can be lethal [5].

Phenibut Withdrawal | What You MUST Know

If an individual takes phenibut occasionally, it might have a similar effect to the GABA that’s already in the system. That means that both the natural GABA and the phenibut are in the nervous system, and they work together to have their effect.

Over time, if an individual continues to use phenibut, their body may begin to develop a tolerance [7]. This may cause the body to slow down the production of natural GABA. When the body gets used to getting its GABA from an outside source, it starts to reduce the amount that it produces naturally.

That is when physical dependence starts to develop. The body starts requiring the substance to function normally [7]. And it may need higher and higher doses to get the same effects as before.
Phenibut withdrawal happens when a frequent user develops tolerance and then stops taking phenibut [8]. When the body grows accustomed to phenibut and ceases its own GABA production, it experiences a shock when the phenibut is discontinued.


Phenibut Withdrawal Symptoms

Phenibut withdrawal symptoms can include [9, 10]:

  • Rebound anxiety
  • Anger
  • Agitation
  • Irritability
  • Insomnia
  • Auditory and visual hallucinations

To mitigate the risk of phenibut withdrawal and associated symptoms, it is important to follow an appropriate dosing schedule.

Read more about how to take phenibut properly here.

When Does Phenibut Withdrawal Start?

A phenibut user needs to develop dependendence before they experience withdrawal.

But physical dependence only affects certain phenibut users. If a user does become dependent, it is usually only after long-term use. So if an individual is participating in a short-term phenibut study, they are unlikely to develop dependence and the consequent withdrawal.

When the body gets used to phenibut and stops producing its own GABA, withdrawal effects may set in as phenibut starts leaving the system.

How Long Does Phenibut Withdrawal Last?

Phenibut withdrawal is different for everyone, so how long it lasts can be different.

Acute symptoms can last a couple of days [9, 10, 11]. After that, depending on the severity of the dependence, there may be residual effects for a few weeks.

How to Treat Symptoms

Any individual who thinks they may have phenibut dependence should seek immediate medical care.

Depending on how much they’re taking and how dependent they are, the physician might consider a variety of therapies to help a dependent individual avoid the worst of the withdrawal effects. An abrupt end of phenibut may be really unpleasant.

Case studies suggest several medications may help with phenibut withdrawal, including [10, 11]:

  • Phenobarbital
  • Propofol
  • Haloperidol
  • Benzodiazepines
  • Baclofen

Under the care of a physician, these may aid in treating withdrawal symptoms. Of course, your test subjects should never self-medicate when dealing with phenibut withdrawal. Guide them to see a medical professional.

Warnings and Concerns

Phenibut should not be used outside of a medical or research context, under the supervision of qualified professionals. Like alcohol and other drugs, there is a real risk of dependence [10, 11].

A person might be at a special risk of developing a dependence on phenibut if they:

  • have a history of substance abuse
  • use phenibut more than two times per week
  • use doses larger than 2.5 grams a day

Phenibut for Benzo Withdrawal

We are aware of unverified reports of phenibut being used to help with withdrawal symptoms arising from benzodiazepine use.

Benzodiazepines are a class of drugs used for a variety of psychological conditions, like anxiety, panic disorder, and insomnia. Like phenibut, these drugs work by mimicking GABA and binding to GABA receptors.

People that use benzodiazepines for a long time can develop dependence issues (in the same way that they can for phenibut). If a person is dependent on benzos and stops taking them, they may experience withdrawal effects.

Phenibut may help reduce these negative withdrawal effects, though there have been no studies published to that effect. Moreover, the FDA has not reviewed or approved phenibut to treat or alleviate benzodiazepine use symptoms.

Any individual with benzodiazepine withdrawal symptoms should be directed to a physician. Special care must be taken to screen phenibut research study participants for benzodiazepine use.


Phenibut for Kratom Withdrawal

Kratom is another substance that acts on the GABA receptors, though not to the extent of phenibut.

Kratom is a plant from the same family as the coffee plant and is native to Southeast Asia. Kratom has opioid properties. As with phenibut, kratom use can lead to addiction and withdrawal symptoms upon discontinuance of use [12].

We are aware of unverified reports of phenibut being used to help with kratom withdrawal symptoms. However, there have been no studies on this potential use of phenibut. Moreover, the FDA has not reviewed or approved phenibut to treat or alleviate symptoms associated with kratom use.

Any individual with kratom withdrawal symptoms, which can include muscle aches, insomnia, and aggression, should be directed to a physician. Special care must be taken to screen phenibut research study participants for kratom use.

Phenibut for Opiate Withdrawal

There is also some debate about the ability of phenibut to help treat opiate withdrawal.

Again, there is simply no published evidence that phenibut is effective to this end.

Any individual with opioid withdrawal symptoms should be treated under the supervision of a physician. Special care must be taken to screen phenibut research study participants for opioid use.

That said, opioid abuse represents a public health crisis across the developing world, with tens of thousands of opioid overdose deaths annually in the United States alone. Treatment breakthroughs are much needed, and phenibut researchers are in a unique position to contribute to the global effort to fight the opioid crisis.

Phenibut for Alcohol Withdrawal

Finally, some reports have identified phenibut being used to tackle alcohol withdrawal symptoms and alcohol cravings [13]. Other research has found that there are recreational users of phenibut that consume it at the same time as alcohol, which is strongly discouraged [14].

One of phenibut’s approved uses in Russia is as a treatment for alcohol dependence [1].

Because it triggers some of the same receptors as alcohol, some research has found that phenibut may be an effective way to reduce the discomfort from alcohol withdrawal [15]. For example, it has been shown in a small group of alcoholics to help improve the length of certain sleep phases [16].

But there remains a paucity of research on the effectiveness of phenibut for treating alcohol withdrawal symptoms. This is a potentially fruitful area of future research.
Nonetheless, alcoholism is a serious condition requiring the intervention of qualified professionals. Phenibut should not be used recreationally, with or without alcohol, nor as a potential treatment of alcohol withdrawal, unless so directed by a physician.


Buy Phenibut Online | 2022 Guide

If you have weighed the benefits of phenibut research against the potential risks, it’s time to look for a reputable supplier.

As a nootropics researcher, you can buy phenibut online in any country in which phenibut is not a controlled substance and is not a prescription medication. This includes the United States and Canada.

But be careful who you buy from. Supplements and new drugs like phenibut are not subject to the same laws as pharmaceutical drugs, which would otherwise force manufacturers to follow high standards of quality control and safety. Want our input?

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Phenibut Withdrawal | Verdict

Phenibut has a variety of potential uses, particularly as a nootropic and anxiolytic, so it warrants further study. There are some reports of phenibut being used to treat withdrawal associated with benzodiazepine, kratom, opioid, and alcohol addiction. Phenibut is not approved for any of these uses in the United States at this time.

With phenibut itself there is a risk of dependence and withdrawal for test subjects. To mitigate the risk of phenibut withdrawal in the context of a research study, follow conservative dosing guidelines and refer any individual with phenibut addiction or withdrawal symptoms to the relevant licensed practitioner.



  1. Lapin I. (2001). Phenibut (beta-phenyl-GABA): a tranquilizer and nootropic drug. CNS drug reviews, 7(4), 471–481. doi:10.1111/j.1527-3458.2001.tb00211.x
  2. Cheung, J. & Penn, J. (2018). Weekly dose: Phenibut. The Conversation.
  3. Ozon Pharm (n.d.), Fenibut (PDF). [In Russian].
  4. Owen, D. R., Wood, D. M., Archer, J. R., & Dargan, P. I. (2016). Phenibut (4‐amino‐3‐phenyl‐butyric acid): Availability, prevalence of use, desired effects and acute toxicity. Drug and alcohol review, 35(5), 591-596.
  5. CDC (2020). Notes from the Field: Phenibut Exposures Reported to Poison Centers — United States, 2009–2019.
  6. Högberg, L., Szabó, I., & Ruusa, J. (2013). Psychotic symptoms during phenibut (beta-phenyl-gamma-aminobutyric acid) withdrawal. Journal of Substance Use, 18(4), 335-338.
  7. Koob, G. F. (1996). Drug addiction: the yin and yang of hedonic homeostasis. Neuron, 16(5), 893-896.
  8. Jouney, E. A. (2019). Phenibut (β-Phenyl-γ-Aminobutyric Acid): An easily obtainable “dietary supplement” with propensities for physical dependence and addiction. Current Psychiatry Reports, 21(4), 23.
  9. Joshi, Y. B., Friend, S. F., Jimenez, B., & Steiger, L. R. (2017). Dissociative intoxication and prolonged withdrawal associated with phenibut: a case report. Journal of Clinical Psychopharmacology, 37(4), 478.
  10. Ahuja, T., Mgbako, O., Katzman, C., & Grossman, A. (2018). Phenibut (β-Phenyl-γ-aminobutyric Acid) Dependence and Management of Withdrawal: Emerging Nootropics of Abuse. Case reports in psychiatry, 2018. doi:10.1155/2018/9864285
  11. Hardman, M. I., Sprung, J., & Weingarten, T. N. (2019). Acute phenibut withdrawal: A comprehensive literature review and illustrative case report. Bosnian Journal of Basic Medical Sciences, 19(2), 125.
  12. Singh, D., Müller, C. P., & Vicknasingam, B. K. (2014). Kratom (Mitragyna speciosa) dependence, withdrawal symptoms and craving in regular users. Drug and alcohol dependence, 139, 132-137.
  13. Samokhvalov, A. V., Paton-Gay, C. L., Balchand, K., & Rehm, J. (2013). Phenibut dependence. Case Reports, 2013, bcr2012008381.
  14. Zheng, K. H., Khan, A., & Espiridion, E. D. (2019). Phenibut Addiction in a Patient with Substance Use Disorder. Cureus, 11(7).
  15. Tiurenkov, I. N., Voronkov, A. V., & Borodkina, L. E. (2005). Effect of phenibut on the behavior of experimental animals under conditions of voluntary chronic alcoholism. Eksperimental'naia i Klinicheskaia Farmakologiia, 68(3), 42-45.
  16. Danilin, V. P., Krylov, E. N., AIu, M., & Rait, M. L. (1986). Effect of fenibut on the nocturnal sleep of patients with the alcoholic abstinence syndrome. Zhurnal nevropatologii i psikhiatrii imeni SS Korsakova (Moscow, Russia: 1952), 86(2), 251-254.

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