Phenibut: A Review
Phenibut is a central nervous system depressant and derivative of the naturally occurring inhibitory neurotransmitter GABA, and it is well-known in the nootropic community for its anxiolytic and cognitive enhancing effects. While Phenibut has been widely researched in Russia —where is available by prescription to relieve tension, anxiety, and fear, to improve sleep in psychosomatic or neurotic patients; as well as a pre- or post-operative medication, depression, and PTSD—, little knowledge exists in Western medicine regarding its properties and long term use effects.
In regard to its chemical structure, phenibut is a phenyl derivative of GABA. The addition of a phenyl ring allows phenibut to cross the blood–brain barrier effectively, albeit there is a considerable amount of anecdotical reports that support that phenibut can take up to three hours to start working . Even though the calming effects of the drug are similar to other GABA agonists, some researchers argue that phenibut binds to the GABAB metabotropic receptor and NOT the GABAA ionotropic receptor one, which is responsible for the actions of the benzodiazepines, barbiturates, Z-drugs, and for some of the effects of ethanol. If this were true, we would consider phenibut a unique drug on its type. There is still dispute in the literature about this important issue that can clarify the controversy of phenibut’s potential withdrawal effects.
For our purposes, it is better to play safe and say that Phenibut acts as a GABA-mimetic, primarily at GABA(B) and, to some extent, at GABA(A) receptors, and might also stimulate dopamine levels , fact that would help explaining the reported mind-stimulating effects of the drug . Indeed, the injection of Phenibut was shown to enhance not only the inhibitory, but also excitatory components of cerebral cortical neuronal responses to all applied stimuli ; and accelerate the acquisition of internal inhibition, even in doses as high as 40mg\kg . Furthermore, Phenibut has been proved to decrease the reactivity of animals to emotionally negative stimuli , hence the interest on its potential antidepressant and anti-anxiety properties.
Furthermore, there have been experiments on mice that indicate that phenibut has pronounced protective properties, from an inmunocorrecting nature to a neuroprotectant one. In this study , phenibut reduced a neuralgic deficiency, amnesia, and the degree of cerebral circulation drop, and improved the spontaneous movement and research activity deteriorated by brain ischemia. Thus, Phenibut (I mg/kg) eliminates the symptoms of GABA-system disturbances revealed upon exposure to stress, decreases the tension of stress reaction and hyperglucocorticoidemia which causes hyperglycemia .
Nevertheless, the main downside of phenibut would be its abuse potential. While the debate of GABAB metabotropic receptor vs. GABAA ionotropic receptor would give more lights to this problematic, the fact is that there have been reports of phenibut dependence already and, as you might have read before, terrible withdrawal stories in reddit . Even though there are as few as 3 official cases descriptions in PubMed -all of them with successful outcomes-, moderation and supervision is urged.