Phenibut is an anxiety drug sold online that can lead to tolerance and dependence. Safety data is lacking for phenibut, so It is not approved for use in the U.S.

Article Overview

  • Phenibut is an anti-anxiety drug developed in Russia and sold online without a prescription.
  • It is not an approved drug in the United States, nor is it a controlled substance.
  • Evidence suggests it may have addictive properties and can cause withdrawal symptoms.
  • Side effects of phenibut include drowsiness and lethargy.

What Is Phenibut?

Phenibut is a GABA-B agonist developed in Russia to treat anxiety, stress and insomnia. Phenibut is not an approved medication in the U.S., nor is it considered an illicit substance. So, at this time, phenibut is legal to possess in the U.S. and is sold online as a supplement.

Since phenibut is not a controlled substance in the United States, there are no regulations as far as how it’s marketed, sold or available. Someone can purchase it online and consume it as they please because there aren’t guidelines for dosages or any similar safety information.

In the United States, people take phenibut as a nootropic. Nootropics are agents that are intended to improve cognitive function and ability, although there’s often little research to back these claims. People may also take phenibut to reduce anxiety, including social anxiety, help them relax and help them fall asleep.

Phenibut likely affects the gamma-Aminobutyric acid (GABA) receptor sites in the brain, spinal cord and nervous system. Phenibut’s structure and function is similar to GABA meaning it calms overexcitement in the brain. When phenibut activates GABA receptor sites, it can create a similar calming effect, reducing anxiety and invoking a sense of calm.

Phenibut was first available in the early 1960s in Russia for patients undergoing psychiatric treatment.

Is Phenibut Addictive?

At this time, the Drug Enforcement Administration has not determined that phenibut is addictive. For this reason, it is not a controlled substance. However, some experts believe it may have addictive properties.

People can also become psychologically dependent on phenibut for different reasons. For example, people may use phenibut to ease social anxiety or mix it with other substances such as alcohol to increase the effects of the substances. Over time, someone who self-medicates to alleviate social anxiety may find they aren’t able to be in social situations without doing so.

Can Phenibut Cause Withdrawal?

Phenibut affects GABA receptor sites and can change the function of the brain’s neurotransmitters. Phenibut dependence can occur relatively quickly — sometimes after using the substance only a few times. In such a situation, a person may have phenibut withdrawal symptoms if they abruptly stop the drug.

These symptoms may include:

  • Rebound anxiety
  • Depression
  • Paranoia
  • Tremors
  • Insomnia
  • Aggression
  • Cognitive deficits or brain fog
  • Nausea
  • Hallucinations

How Phenibut Works

Phenibut is considered a psychotropic drug. These types of drugs affect a person’s mental state. The structure and chemical makeup of phenibut are both similar to the naturally occurring brain neurotransmitter gamma-aminobutyric acid (GABA).

GABA reduces neural excitability and anxiety. When someone takes phenibut, the person may feel more relaxed because it’s activating GABA receptors. Taking phenibut may also help with insomnia.

Side Effects of Phenibut

Phenibut side effects can vary in severity and type. Some of the most commonly reported phenibut side effects include:

  • Drowsiness 
  • Lethargy 
  • Agitation 
  • Fast heartbeat 
  • Confusion

Because phenibut isn’t an approved medication, there is limited oversight of the ingredients that manufacturers include in their products. Always consult with your primary care provider before taking any new medicine or supplements.

Long-Term Side Effects of Phenibut Use

One of the primary long-term side effects of phenibut use involves developing phenibut tolerance. This development means that someone requires larger doses of phenibut to achieve the desired effects. 

Along with tolerance can come dependence. When someone is dependent on phenibut, withdrawal symptoms may occur if they stop using it. Potential phenibut withdrawal symptoms include anxiety, agitation and psychosis.

Signs of Phenibut Abuse

Phenibut abuse can occur anytime a person continues using the substance in spite of negative consequences, side effects or outcomes. For example, if someone experiences hallucinations or tremors after taking phenibut, but continues to use it to feel relaxed, this is a sign of abuse.

Drug overdoses can be fatal. If you suspect someone is experiencing an overdose, administer naloxone (Narcan) if you have it available and call 911 immediately. Do NOT be afraid to seek help. If you do not have access to a phone, contact Colorado Poison Center for online assistance.

An overdose can occur because of phenibut abuse. Signs of a phenibut overdose include unresponsiveness. Because phenibut is a central nervous system (CNS) depressant, the risk of a phenibut overdose may increase if it’s used with other CNS depressants. Some other CNS depressants include alcoholopioids and benzodiazepines.

Finding Help for Phenibut Addiction

If you are struggling with phenibut addiction or dependence, The Recovery Village at Palmer Lake can help. Contact a representative at The Recovery Village at Palmer Lake to learn about treatment programs for substance use disorders. You can achieve a substance-free life, call today to get started.

Editor – Rob Alston
Rob Alston has traveled around Australia, Japan, Europe, and America as a writer and editor for industries including personal wellness and recovery. Read more
Medically Reviewed By – Dr. Jessica Pyhtila, PharmD
Dr. Jessica Pyhtila is a Clinical Pharmacy Specialist based in Baltimore, Maryland with practice sites in inpatient palliative care and outpatient primary care at the Department of Veteran Affairs. Read more

Graves, Janessa M.; Dilley, Julia; Kubsad, Sanjay; Liebelt, Erica. “Notes from the Field: Phenibut Exposures[…] States, 2009–2019,” Centers for Disease Control and Prevention, Morbidity and Mortality Weekly Report, September 4, 2020. Accessed June 6, 2021.

Lapin, Izyaslav. “Phenibut (beta-Phenyl-GABA): A Tranquili[…]r and Nootropic Drug,” CNS Drug Reviews, 2001. Accessed June 6, 2021.

Michigan Medicine Department of Psychiatry. “Phenibut: The Russian Cosmonaut Drug You[…]ne to Reduce Anxiety.” October 21, 2020. Accessed June 6, 2021.

Medical Disclaimer

The Recovery Village at Palmer Lake aims to improve the quality of life for people struggling with substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare providers.