Phenibut (β-phenyl-γ-aminobutyric acid HCl) is structurally similar to GABA (γ-aminobutyric acid), one of the most prevalent inhibitory neurotransmitters in the human central nervous system. Phenibut was synthesized in Russia in 1964, and since then much of the research has come out of Russian research institutions. In Russia, phenibut is used clinically to treat certain psychiatric disorders, alcohol withdrawal, and sleep disturbances.1Anecdotally, phenibut is used by some biohackers to improve sleep quality, and enhance cognition. However, there is no publication demonstrating a nootropic effect of phenibut in healthy adults.
Structure of GABA and Phenibut
Pharmacology of Phenibut
Phenibut was originally designed to be an analog of GABA that is capable of crossing the blood-brain barrier upon oral ingestion. And indeed, the addition of the phenyl ring to GABA, producing phenibut, does allow it to cross the blood-brain barrier.2The effects of phenibut effects are likely due to its effect on GABA signaling pathways – either by directly interacting with GABA receptors or by promoting endogenous GABA release.
Nootropic Effects of Phenibut
The only studies of nootropic effects for phenibut are in animals. In one study, phenibut was found to enhance the conditioned response to a form of fear/threat learning in mice, at a dose of 5 mg/kg. There is no evidence for an effect of phenibut on attention, working memory, or long-term memory.