Other Name(s):

4-Amino-3-Phenylbutyric Acid, Acide 4-Amino-3-Phenylbutyrique, Acide Bêta-phényl-gamma-aminobutyrique, Agente Gabaérgico, B-Phenyl-Gamma-Aminobutyric Acid, Beta-Phenyl-GABA, Bêta-Phényl-GABA, Beta-phenyl-gamma-aminobutyric acid, Fenibut, Phénibut, Phenyl-GABA, Phényl-GABA.


Phenibut is a chemical similar to a brain chemical called gamma-aminobutyric acid (GABA). It is used as medicine.

Phenibut is used for anxiety, fear, trouble sleeping (insomnia), tension, stress, fatigue, post-traumatic stress disorder (PTSD), depression, alcoholism, and irregular heartbeat. It is also used for improving memory, learning, and thinking.

How does it work?

Phenibut is similar to the brain chemical called gamma-aminobutyric acid (GABA). Research in animals shows that it might decrease anxiety and have other effects on the body. But phenibut has not been studied in people, so no one knows whether it might work as a medicine.


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Uses & Effectiveness

Insufficient Evidence to Rate Effectiveness for...

  • Anxiety.
  • Alcoholism.
  • Irregular heartbeat.
  • Fear.
  • Insomnia.
  • Tension.
  • Stress.
  • Fatigue.
  • Post-traumatic stress disorder (PTSD).
  • Depression.
  • Improving memory, learning, and thinking.
  • Other conditions.
More evidence is needed to rate the effectiveness of phenibut for these uses.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).

Side Effects

There is not enough information to know if phenibut is safe. It has not been studied in people.


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Special Precautions & Warnings

Pregnancy and breast-feeding: not enough is known about the use of phenibut during pregnancy and breast-feeding. stay on the safe side and avoid use.


The appropriate dose of phenibut depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for phenibut. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.

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Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.


Anon. [The influence of agonist of GABA-receptor--phenibut on behavior and respiration of rabbits in negative emotional situation]. Zh Vyssh Nerv Deiat Im I P Pavlova 2007;57:479-88. View abstract.

Perfilova VN, Tiurenkov IN, Berestovitskaia VM, Vasil'eva OS. [Cardioprotective effect of GABA derivatives in acute alcohol intoxication]. Eksp Klin Farmakol 2006;69:23-7. View abstract.

Shul'gina GI, Ziablitseva EA. [Effect of the GABA derivative phenibut on learning]. Vestn Ross Akad Med Nauk 2005;(2):35-40. View abstract.

Talalaenko AN, Krivobok GK, Pankrat'ev DV, Goncharenko NV. Neurochemical mechanisms of the dorsal pallidum in the antiaversive effects of anxiolytics in various models of anxiety. Neurosci Behav Physiol 2006;36:749-54. View abstract.

Talalaenko AN, Pankrat'ev DV, Bulgakova NP. [Neurochemical features of the ventral pallidum in realization of the antiaversive effects of anxiolytics in different models of anxiety]. Eksp Klin Farmakol 2006;69:6-11. View abstract.

Tarakanov IA, Tarasova NN, Belova EA, Safonov VA. [Effect of phenibut on the respiratory arrest caused by serotonin]. Eksp Klin Farmakol 2006;69:28-32. View abstract.

Tiurenkov IN, Bagmetov MN, Epishina VV, et al. [Comparative evaluation of the neuroprotective activity of phenibut and piracetam under experimental cerebral ischemia conditions in rats]. Eksp Klin Farmakol 2006;69:19-22. View abstract.

Tiurenkov IN, Voronkov AV, Borodkina LE. [Effect of phenibut on the behavior of experimental animals under conditions of voluntary chronic alcoholism]. Eksp Klin Farmakol 2005;68:42-5. View abstract.

Ziablintseva EA. [The effect of GABA derivative phenibut on defensive conditioning and internal inhibition]. Zh Vyssh Nerv Deiat Im I P Pavlova 2006;56:236-41. View abstract.

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