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Phenibut 101

Phenibut is central nervous system depressant first synthesized by Professor Vsevolod Perekalin at the USSR Academy of Medical Sciences in the 1950s. First introduced into clinical use in the 1960s, Phenibut has enjoyed a long history of use over the past 60 years making it one of the oldest developed nootropics. In its early days, it was sent into space with cosmonauts to deal with the anxiety of space flight without affecting their ability to operate machinery. It is prescribed for the treatment of anxiety and insomnia, among other ailments, in Russia, Ukraine, Kazakhstan, and Latvia as the pharmaceutical Noofen.

The chemical structure of Phenibut

Is Phenibut Legal?

The answer to that question depends on where you live. While used for medical purposes in Russo-European countries, in the western world the drug is not approved to treat any ailments. However, Phenibut is not scheduled and is freely available in all countries with the exception of Australia. In February 2018, the Therapeutic Goods Administration of Australia listed Phenibut as a Prohibited Substance, criminalizing possession, use, sale or manufacture of the drug within Australian borders. For now, Phenibut remains freely available and easily found in the rest of the world.

What are the effects of Phenibut?

Phenibut’s effects include anxiolysis, hypnosis, nausea reduction, reduction of tics and stuttering, as well as general feelings of well-being. A recent study that looked at Phenibut in relation to ADHD found Phenibut, at a dose of 500 mg daily, improved anxiety and impassivity in teenagers that suffered from the ailment with a 63% success ratei. A 2014 study found that at 1000 mg a day, Phenibut improved attention, memory, and emotional intelligence in almost 3 out of every 4 patients that suffered from social anxietyii. Phenibut might turn out to be a better treatment for social anxiety due to its lower potential for abuse than traditional anti-anxiety medications such as Xanax, as well as its relatively benign profile of physical side effects.

Members of nootropic communities on sites like Reddit often attribute other effects to Phenibut such as claiming that it has stimulating, anti-depressant, or pro-cognitive effects. While these are theoretically possible, there is little to no clinical evidence that these are the results that a healthy individual can expect when taking Phenibut. That being said, recent studies have found Phenibut to be a possible treatment for improved attention in those suffering from social anxiety (as mentioned above). One hypothesis to explain this effect is that when someone suffering from social anxiety has that anxiety relieved they are less distracted by their ailment and able to put more attention towards cognitive tasks.

How does Phenibut work?

Phenibut is a GABAergic drug, meaning that it works on the GABA receptors in the brain. GABA receptors are the primary inhibitory receptors of the brain and function by opening a channel that allows chloride ions that carry a negative charge into the cell or positively charged potassium ions out of the cell depending on the what type of GABA receptor it is. Either way, the net effect is the same: the receptor activation causes the neuron to become more negatively charged in relation to its surroundings, a state known as hyperpolarization. This makes it less likely the neuron will fire in the case of an incoming signal from a connecting neuron.

When looking at the structures of the neurotransmitter GABA and Phenibut side by side it is easy to see the similarity in their structure. The only difference is the addition of a phenyl group on the β carbon. This is how Phenibut gets its name: β-Phenyl-γ-aminobutyric acid.

There are two primary GABA receptors GABAand GABAB. Phenibut works almost exclusively by agonizing the GABAreceptor, with GABAactivity only becoming apparent during very high doses. While there aren’t hard and fast rules that differentiate the effects of the two receptors on the human level, something can be gleaned from the fact that agonists (activators) of GABAA include Xanax, Klonopin, and Ethanol.

What type of Phenibut should I buy?

Phenibut is available in several different forms. In this section, we will go through a few of the available versions of Phenibut and list their positives and negatives.

Phenibut HCl

This is the gold-standard of Phenibut. For much of its history, this is the form that has been in the widest use and most readily available. It is very water soluble, orally bio-available, and has a consistent dosing pattern. Almost all of the dosages you read online or in scholarly articles are using the HCl salt. The only downside has to do with its acidity. If your stomach is easily upset, the acidity of Phenibut HCl may cause you to feel sick under certain circumstances. Drinking a glass of water with Phenibut HCl is unpleasant due to its intensely acidic taste.

Phenibut FAA

This is the free amino acid version of Phenibut. It has a neutral pH making it much easier to ingest by methods other than oral, as it can come into direct contact with mucous membranes without discomfort. This allows one to do sublingual dosing. This a very cost-effective version of Phenibut, since potency is increased by about three times, when taken sublingually, according to anecdotal reports on sites like Reddit. To add to this, it is also 15% more potent than the HCl salt when consumed orally. However, anecdotal reports claim Phenibut FAA has a slower onset when taken orally when compared to the HCl salt.

Phenibut XT

Phenibut XT is a popular preparation of Phenibut that is simply Phenibut HCl with filler in 500 mg capsules. The main advantage is easy dosing. The downside is the lack of ability to titrate your dose. You will also pay a premium for the convenience of buying a pill form.


Also known as Fluorophenibut, Fluorobut, and 4F-Phenibut. Unlike the other forms of Phenibut this is actually an entirely different molecule, having the addition of a Fluorine atom in the 4th position of the phenyl ring on Phenibut. Like Phenibut it is highly selective for the GABAreceptor over the GABAreceptor, however, based on anecdotal reporting the potency seems to be increased by an order of magnitude over Phenibut. Because of the relative newness of this chemical it still remains to be seen how safe it is with moderate use. Currently, it seems to share a similar risk profile as Phenibut itself. Most users report that the two molecules are almost indistinguishable in effect, and only requiring different dosages.

Things to consider when buying Phenibut

When buying Phenibut make sure that you are buying the product from a trustworthy source that has their products tested and has that testing available for review. When dealing with white powders you can never be too careful making sure you are getting the correct substance. Additionally, a scale is required to dose the compound, although a scale with a resolution of 0.1 grams is enough for this compound.

Finally, for all the good this supplement can do it does have the ability to be abused. While not as addictive as other GABA agonists, it still carries a moderate risk of addiction that should not be taken lightly. To add to this tolerance develops with regular use very quickly and for that reason it is recommended that research subjects only dose one to two times a week, ideally leaving several days in between.

Feel free to head over to our store to see the types of Phenibut we have in stock!


i Chutko LS, Surushkina EY, Yakovenko EA, Kroptov YD, Anisimova TI, Sergeev AV (2016). “Impulsivity in adolescents with attention deficit hyperactivity disorder”. Zh Nevrol Psikhiatr Im S S korsakova

ii Chutko LS, Surshkina Slu, Iakovenko EA, Nikishena IS, Anisimova TI, Bondarchuk Iul (2014). “Cognitive and emotional impairments in patients with protracted anxiety-phobic disorders”. Ter Arkh