Hence, it is a GABA analogue. Phenibut is specifically the analogue of GABA with a phenyl ring substituted in at the β-position.
As such, its chemical name is β-phenyl-γ-aminobutyric acid, which can be abbreviated as β-phenyl-GABA. The presence of the phenyl ring allows phenibut to cross the blood–brain barrier significantly, unlike the case of GABA.