Home » An In-Depth Look at Phenibut: Usage, Dosage, and Effects

An In-Depth Look at Phenibut: Usage, Dosage, and Effects


Phenibut, a substance similar in structure to the brain chemical gamma-aminobutyric acid (GABA), has been a topic of interest in the field of neuropharmacology since its development in Russia during the 1960s 1 Trusted source
National Institute of Health
Go to source
This compound, known by various names such as Noofen, Fenibut, Phenybut, and Citrocard, has been utilized both as a nootropic and a recreational drug 2 Trusted source
National Institute of Health
Go to source
. This article aims to provide a comprehensive overview of Phenibut, its usage, dosage, and effects, based on the information available in the scientific literature cited.

Phenibut: An Overview

Phenibut is a depressant and is structurally similar to GABA, the primary inhibitory neurotransmitter in the brain4. This similarity has been reported to contribute to its anxiolytic (anxiety-reducing) and mood-enhancing effects5. Phenibut has been used to treat a variety of conditions, including insomnia, post-traumatic stress disorder (PTSD), stress, tension, depression, alcoholism, fatigue, anxiety, fear, balance disorders, irregular heartbeat, and appetite control3.

Despite its potential benefits, Phenibut is not approved for clinical use in many parts of the world, including the United States. However, it is available as a nutritional supplement and is legal to possess without a prescription, provided no therapeutic claims are made that counter Food and Drug Administration (FDA) guidelines3.

Forms of Phenibut

Phenibut is available in two distinct forms: Phenibut HCL and Phenibut FAA. Phenibut HCL is a salt form that readily dissolves in water. This makes it convenient to consume in a drink, or it can be taken in capsule form for ease of use.

On the other hand, Phenibut FAA is a free-form amino acid. This form is not as soluble as the HCL version. Typically, it’s taken sublingually, which means it’s placed under the tongue. It can also be taken in pill form for those who prefer it.

Although Phenibut FAA tends to be pricier than Phenibut HCL, it contains more of the active compound by weight. This means users can take a lower dose compared to HCL, which can make it more cost-effective in the long run.

Dosage and Administration

Determining an appropriate dosage for Phenibut can be challenging due to the lack of comprehensive scientific data. Factors such as the user’s age, body weight, state of health, and other health-related conditions should be considered3. For first-time users, a starting dose of 250-500 mg is recommended, with a maximum daily dose of 1.5 grams (1500 mg). It is also advised not to take Phenibut more than three days a week to prevent tolerance and potential addiction3.

Phenibut Dosage for Anxiety, Sleep, and Microdosing

To study the effects of Phenibut in social situations or as an anxiolytic, first-time users may be given 250mg to 350mg per day. This should be split into 1 to 3 doses and taken at least one hour before food.

For sleep benefits, the dosage might be increased to 500mg to 750mg per day. This should also be split into 1 to 3 doses and taken at least one hour before food.

Some users have reported positive effects from very small doses of Phenibut, less than 20 mg per kilogram of body weight. A microdose for a study might be 50mg to 100mg per day, taken at least one hour before food.

This pie chart illustrates that Phenibut should be taken no more than three days a week, which is approximately 43% of the week. The remaining 57% of the week, Phenibut should not be taken. This is in line with the guidance to prevent tolerance and potential addiction. These are general guidelines and the actual usage should be determined in consultation with a healthcare provider.

Phenibut can be administered in capsule or powder form. The powder form should be mixed with warm water or another warm beverage to facilitate dissolution and absorption3. It is recommended to take Phenibut on an empty stomach, as food can delay its effects3.

Conditions Phenibut Has Been Used to Treat
Post-Traumatic Stress Disorder (PTSD)
Balance disorders
Irregular heartbeat
Appetite control

How to Take Phenibut

Phenibut can be taken in capsule or powder form. If you opt for the powder form, it should be mixed with warm water or another warm beverage of your choice. The warmth helps to activate the Phenibut crystals, allowing them to dissolve quickly and enter the bloodstream rapidly.

It’s also possible to take Phenibut sublingually, which means placing it under the tongue for faster absorption and entrance into the bloodstream.

Each dose of Phenibut should ideally be taken on an empty stomach. Consuming it with food can delay the full benefits of the supplement. It’s recommended to wait at least 45 minutes after eating before taking Phenibut to allow it to work effectively.

Safety Considerations

While Phenibut can have beneficial effects, it should be used with caution. Combining Phenibut with alcohol can overstimulate GABA receptors, potentially leading to hazardous health effects3. Furthermore, regular use of Phenibut can lead to tolerance and addiction, with withdrawal symptoms including loss of appetite, nausea, anxiety, and insomnia3.

Phenibut should not be used by pregnant or breastfeeding women due to insufficient safety data. If you’re using Phenibut regularly, be aware that suddenly stopping can lead to withdrawal symptoms such as loss of appetite, nausea, anxiety, insomnia, and muscle aches. Individuals planning to use Phenibut should consult with a healthcare provider or a natural supplement expert before starting supplementation3.

Exploring the Scientific Evidence for Phenibut’s Effects and Uses

Phenibut’s effects and uses have been the subject of several scientific studies, particularly given its potential as a nootropic and anxiolytic substance.

One of the key studies on Phenibut was conducted by Lapin in 20011, where he described Phenibut as a tranquilizer and nootropic drug. The study highlighted Phenibut’s similarity to GABA, a neurotransmitter that inhibits brain activity and produces a calming effect. This similarity is believed to contribute to Phenibut’s anxiolytic (anxiety-reducing) and mood-enhancing effects.

In a 2008 study by Shul’gina and Ziablitseva4, the researchers examined the effect of Phenibut on learning. They found that Phenibut could enhance cognitive function, particularly in terms of improving memory and intellectual performance. This has led to Phenibut’s popularity as a nootropic, a substance that can enhance cognitive function.

Phenibut’s potential as a treatment for various conditions has also been explored. For instance, it has been used to treat conditions like insomnia, PTSD, stress, and anxiety. However, it’s important to note that while there are anecdotal reports and some research supporting these uses, more comprehensive studies are needed to fully understand Phenibut’s efficacy and safety in these areas.

Safety is a significant concern with Phenibut use. A study by Owen et al. in 20165 highlighted the potential risks associated with Phenibut. The researchers found that combining Phenibut with alcohol could overstimulate GABA receptors, leading to hazardous health effects. Furthermore, regular use of Phenibut could lead to tolerance and addiction, with withdrawal symptoms including loss of appetite, nausea, anxiety, and insomnia.

While there is scientific research supporting some of the claims about Phenibut’s effects and uses, more research is needed, particularly regarding its long-term effects, potential interactions with other substances, and safety considerations. As always, it’s crucial for individuals to consult with a healthcare provider before starting any new supplement regimen.

Long Term Phenibut Use & Interactions

Long-term use of Phenibut can lead to dependence and withdrawal6. Symptoms of withdrawal can include severe anxiety, agitation, and restlessness7. In some cases, withdrawal from Phenibut can lead to psychosis10.

Phenibut can interact with other substances and medications. For example, it can interact with alcohol, leading to increased sedation and potentially dangerous respiratory depression8. It can also interact with other central nervous system depressants, such as benzodiazepines, leading to increased sedation and potentially dangerous respiratory depression9.

Phenibut can also interact with pregabalin (Lyrica), a medication used to treat nerve pain and fibromyalgia. Both Phenibut and pregabalin act on the brain in a similar way, and taking these two chemicals together might increase the risk for side effects 11.

Individual Experiences

Individual experiences with Phenibut can vary widely. Some people report positive effects such as reduced anxiety and improved sleep, while others report negative effects such as dizziness, nausea, and in severe cases, unconsciousness12.

It’s important to note that Phenibut is not approved by the FDA for any medical use, and its safety and efficacy have not been thoroughly evaluated in clinical trials. Therefore, it should be used with caution and under the supervision of a healthcare provider.


Phenibut, while offering potential benefits such as reduced anxiety and mood enhancement, should be used with caution due to its potential for tolerance and addiction. More research is needed to fully understand its effects and to establish comprehensive dosage guidelines. As with any supplement, it is crucial to consult with a healthcare provider before starting Phenibut supplementation.


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 https://pubmed.ncbi.nlm.nih.gov/11830761/

2: Samokhvalov AV, Paton-Gay CL, Balchand K, Rehm J. (2013). Phenibut dependence. BMJ Case Reports, 2013, bcr2012008381. doi: 10.1136/bcr-2012-008381 https://pubmed.ncbi.nlm.nih.gov/23391959/

3: Nootropics.com. (2023). Phenibut Dosage Guide: How to Take Phenibut. Retrieved from https://nootropics.com/phenibut-dosage/

4: Shul’gina GI, Ziablitseva EA. (2008). Effect of the GABA derivative phenibut on learning. Neuroscience and Behavioral Physiology, 38(3), 267-272. doi: 10.1007/s11055-008-9026-0 https://link.springer.com/article/10.1007/s11055-008-9025-2

5: Owen DR, Wood DM, Archer JR, Dargan PI. (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. doi: 10.1111/dar.12356 https://pubmed.ncbi.nlm.nih.gov/26693960/

6:Ahuja T, Mgbako O, Katzman C, Grossman A. Phenibut (β-Phenyl-γ-aminobutyric Acid) dependence and management of withdrawal: Emerging nootropics of abuse. Case Rep Psychiatry. 2018;2018:9864285. https://pubmed.ncbi.nlm.nih.gov/29854531/

7:Esposito CM, Mandolini GM, Delvecchio G, Fiorentini A, Brambilla P. Psychomotor agitation non-responsive to treatment: a case report of phenibut withdrawal syndrome. Front Psychiatry 2021;12:688147. https://pubmed.ncbi.nlm.nih.gov/34262493/

8:Owen DR, Wood DM, Archer JR, Dargan PI. Phenibut (4-amino-3-phenyl-butyric acid): Availability, prevalence of use, desired effects, and acute toxicity. Drug Alcohol Rev. 2016 Sep;35(5):591-6. https://pubmed.ncbi.nlm.nih.gov/26693960/

9:McCabe DJ, Bangh SA, Arens AM, Cole JB. Phenibut exposures and clinical effects reported to a regional poison center. Am J Emerg Med. 2019 Nov;37(11):2066-2071. doi: 10.1016/j.ajem.2019.02.044. Epub 2019 Mar 9. PMID: 30878413. https://pubmed.ncbi.nlm.nih.gov/30878413/

10:Acosta E, Munguti C. Acute Psychosis Associated with Phenibut Ingestion. Kans J Med. 2021 Dec 2;14:308-309. doi: 10.17161/kjm.vol14.15550. PMID: 34888004; PMCID: PMC8647977. https://pubmed.ncbi.nlm.nih.gov/34888004/

11:WebMD. Phenibut Interactions. Retrieved from https://www.webmd.com/vitamins/ai/ingredientmono-1184/phenibut

12:Hardman MI, Sprung J, Weingarten TN. Acute phenibut withdrawal: A comprehensive literature review and illustrative case report. Bosn J Basic Med Sci. 2019 May 20;19(2):125-129. doi: 10.17305/bjbms.2018.4008. PMID: 30501608; PMCID: PMC6535394. https://pubmed.ncbi.nlm.nih.gov/30501608/

Scroll to Top