Phenibut is a GABA-mimetic psychotropic drug that is clinically used in its racemic form. The preparation possesses anxiolytic and nootropic activity and it is used as a mood elevator and a tranquilizer. But what form of phenibut is more effective?


Structurally, phenibut is similar to baclofen, another clinically used GABA receptor agonist. Both baclofen and phenibut are used clinically in their racemic forms even though they could be separated into R- and S-enantiomers. Why does it matter?

There are two types of GABA (γ-aminobutyric acid) receptors in the brain: GABA-A and GABA-B. And both of them affect the brain in different ways. So, the R-enantiomer of phenibut mostly has an impact on GABA-B receptors and is shown to be much more effective than S-enantiomer. Interestingly, but the same thing is observed for baclofen, which is also a GABA-B receptor agonist.

In the research devoted to the comparison of these two isomers of the substance along with its racemic form, it’s shown that the antidepressant, antinociceptive, and locomotor depressing activity of racemic phenibut relies on R-enantiomer and correlates to the binding affinity of enantiomers of phenibut to GABA-B receptors.


It’s believed that the version of Phenibut that is sold in Russia is much more effective. In fact, it’s impossible to say for sure, since the preparations should be tested for isomers first. It’s pretty difficult to conduct such testing, and at the moment, we have never heard if such research has ever been done. In Russia, there is a lot of different versions of the preparation manufactured by different companies. The pricing varies pretty much, as does the effect. This can be explained, among other things, by the use of different isomers of the substance.

The difference between the Russian and American versions of the preparation lies mainly in the dosage. It’s 250 mg in one pill which fits perfectly for the treatment (in most cases) and somehow it’s never an option in the US.


It’s definitely not always a good idea. Phenibut is a pretty strong medication that should be only used when prescribed. It’s always better to try something more gentle and mild first, such as Selank, Afobazole, Mexidol, and others.

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