From Self-sufficiency
Jump to: navigation, search
Systematic (IUPAC) name
4-amino-3-phenyl-butanoic acid
Clinical data
Routes of
Legal status
Legal status
Pharmacokinetic data
Biological half-life 5 hours
CAS Number 1078-21-3
ATC code none
PubChem CID 14113
Synonyms Fenibut, Phenybut, PhGABA
Chemical data
Formula C10H13NO2
Molar mass 179.216 g/mol[[Script error: No such module "String".]]
Script error: No such module "collapsible list".
Physical data
Melting point 253 °C (487 °F)
Script error: No such module "TemplatePar".Expression error: Unexpected < operator.

Beta-phenyl-gamma-aminobutyric acid, better known as Phenibut or less commonly Fenibut or Phenybut, is natural derivative of the inhibitory neurotransmitter GABA (Gamma amino butyric acid). Sold as a dietary supplement in the US while in Russia sold as a neuropsychotropic drug that is capable of passing the blood-brain barrier. Phenibut is cited as a nootropic for its ability to improve neurological functions. It was discovered in the Soviet Union in the 1960s, and has since been used there to treat a wide range of ailments including anxiety and insomnia.

The name Phenibut, along with many of the other names for the compound, comes directly from the chemical name for the compound, beta-phenyl-gamma-aminobutyric acid.

The d-isomer is the only biologically active isomer.


Phenibut was synthesized at the I. M. Herzen Leningrad Pedagogical Institute USSR and the Institute of Experimental Medicine, Academy of Medical Sciences USSR by Professor V. V. Perekalin's team.

Phenibut is mandated standard equipment in a Russian cosmonaut's medkit. Conventional tranquilizers' use for stress and anxiety makes patients drowsy, which was deemed unacceptable for cosmonauts, while Phenibut lowered stress levels without affecting performance adversely.

In 1975 Phenibut was included in the cosmonauts' kit for those who participated in the Apollo-Soyuz joint mission.

General information

In chemical structure, Phenibut can be regarded as a phenyl derivative of GABA, as well as a derivative of phenethylamine.

Phenibut has nootropic activity and a tranquilizing effect, reduces stress and anxiety, improves sleep, and may potentiate the effects of tranquilizers, narcotics, and neuroleptics. It also has an anticonvulsant effect.

Physical properties

White crystalline powder. The taste is sour. Very easily soluble in water, soluble in alcohol, the pH of water (2.5%) solution is about 2.3-2.7. As such, ingestion of phenibut can cause gastroesophageal reflux.


Commonly recommended doses are 250-3,000 mg as needed or daily with weekly cycling off during weekends.


Structurally, phenibut is gamma-aminobutyric acid with a phenyl group in the beta position. It has structural similarities to baclofen and phenethylamine. Phenibut is a GABAB receptor agonist, with slight activity at GABAA[clarification needed] receptors. It also is a beta-phenylethylamine antagonist[clarification needed] and thus reduces the effects of phenylethylamine and other compounds that raise phenlethylamine levelsEmpty citation (help) .

Furthermore, it has shown to stimulate dopamine receptors. The pharmacological effects of phenibut are similar to baclofen, but less potent per milligram of dosage.[citation needed]

Contraindications and side effects

Phenibut can have extremely unpleasant dose-dependent withdrawal symptoms. Withdrawal symtoms can include acute anxiety and insomnia that can last for up to two weeks afterwards. Withdrawal symptoms, however, are almost always associated with cessation after prolonged usage.

Phenibut is not to be mixed with alcohol, sedatives or prescription medication without consulting with a healthcare professional.

Persons on MAO inhibitors or epilepsy medications like carbamazepine or oxcarbazepine should consult with their physician or pharmacist prior to supplementation with phenibut. Clinical research has demonstrated that phenibut can potentiate or inhibit the function of some epilepsy medications.[citation needed]


  • Shulgina GI (1986). "On neurotransmitter mechanisms of reinforcement and internal inhibition". Pavlov J Biol Sci. 21 (4): 129–40. PMID 2431377. 
  • Chojnacka-Wójcik E, Hano J, Sieroslawska J, Sypniewska M (1975). "Pharmacological properties of gamma-animobutyric acid and it derivatives. IV. Aryl gaba derivatives and their respective lactams". Arch. Immunol. Ther. Exp. (Warsz.). 23 (6): 733–46. PMID 1241266. 
  • Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
  • Talalaenko AN, Pankrat'ev DV, Goncharenko NV (2002). "[Monoaminergic and aminoacidergic mechanisms of the posterior hypothalamus in realization of the antiaversive effects of anxiosedative and anxioselective agents in various anxiety models]". Eksp Klin Farmakol (in Russian). 65 (5): 22–6. PMID 12596508. 
  • Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
  • Kresiun VI (1984). "[Mg2+-ATPase activity of brain mitochondria fractions in chronic stress and its correction by psychotropic agents]". Ukr. Biokhim. Zh. (in Russian). 56 (6): 637–41. PMID 6151270. 
  • Karkishchenko NN, Dimitriadi NA (1991). "[The adequacy of a new method for assessing the vestibular protective effect of biologically active substances]". Farmakol Toksikol (in Russian). 54 (5): 14–6. PMID 1800137. 

External links


ru:Фенибут sv:Phenibut