Phenibut

Phenibut is a central nervous system depressant developed in the Soviet Union in the 1960s, primarily used in Russia and some Eastern European countries to treat anxiety, insomnia, and other conditions like PTSD, depression, and alcohol withdrawal

It’s a synthetic analog of GABA (gamma-aminobutyric acid), a neurotransmitter that reduces brain cell excitability, with a phenyl ring that allows it to cross the blood-brain barrier more effectively than GABA

Phenibut acts mainly as a GABAB receptor agonist, similar to baclofen, and at higher doses may affect GABAA receptors, like benzodiazepines

It also mildly increases dopamine levels at low doses, contributing to its anxiolytic and euphoric effects