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Phenibut Review – 8 Facts You Need to Know

By Sasha de Beausset Aparicio, MSc

Reviewed by Rebecca Williams, MD, MA, MB, BChir

Last Updated:

Evidence Based | Synopsis | Nutrition Info | Pros & Cons | Contraindications | Cost | Suggested Use | Conclusion

Phenibut is a neuropsychotropic dietary supplement recommended as an anxyolitic. The formula is offered by an American supplier of nutritional formulations called Nutraceutics RX. Official information about this manufacturer or its activity is not accessible to us. This is why it is very hard to assess the company’s compliance with FDA and GMP regulations or the quality of their range of supplements.

This formula is based on a single active ingredient similar to the inhibitory neurotransmitter GABA, but it is claimed as more effective in crossing the blood brain barrier. In fact, there are many concerns (and research is ongoing in this direction) about the actual amount of supplemental GABA that actually penetrates the blood-brain barrier.

The supplement is advertised to act as a GABA-mimetic, primarily at GABA(B) and also stimulates Dopamine receptors. It is designed for adults affected by the numerous daily stress factors by reducing their negative effect while increasing focus and concentration capacities. The key ingredient is Phenibut, also known as beta-phenyl-gamma-aminobutyric acid, discovered in the 1960’s in Russia and used initially to alleviate symptoms of tension, anxiety and fear, post-traumatic stress, improve sleep and symptoms of conditions characterized by depression or asthenia.

Unfortunately, there is not a lot of information available about Phenibut’s action mechanism or the associated unwanted effects. An official source that provides this kind of information could not be found.


1) Phenibut at a Glance

The active substance of Phenibut has been used as an ingredient of anti-anxiety products for more than 60 years. The substance’s benefits were first noticed by conducting in vitro tests on animals. Its effects have been compared to those of diazepam and Piracetam. Today, the number of scientific references is much higher (over 300 hundred). This compound is believed to increase GABA levels in the brain due to its ability to easily penetrate the blood brain barrier. Gama aminobutyric acid is a natural chemical produced in the human brain shown to be responsible for the brain’s response to stress, promote lean muscle growth, relieve pain, and stabilize blood pressure. The benefits of appropriate GABA levels are reduced anxiety feelings and overall body fat, improved physical performance and other conditions. The important neurotransmitter acts as an inhibitory by blocking communication between brain cells.

The key substance in Phenibut is a beta-derivative of GABA demonstrated to have the strongest sedative effect from all derivatives of GABA. The advantages of using such a compound as opposed to GABA have been observed in clinical trials on two different levels: effectiveness and side effects (it lacks the anticonvulsant effects usually associated with the use of GABA supplements). Animal studies also support the compound’s nootropic activity, tranquilizing and anxyolitic effects. The benefits of Phenibut on sleep also seem to be of high interest, and it seems like the effects of the substance in this area are unmatched.

Nutrition Info

2) Ingredients of Phenibut

Phenibut contains the following ingredients: Phenibut, gelatin, and rice flower.

3) What Does Phenibut Do?

Phenibut is an amino acid supplement that contains GABA, an amino acid that plays a key role in regulating neuronal excitability throughout the nervous system. In humans, this amino acid is also directly responsible for the regulation of muscle tone.

It is important to note that in general, GABA does not cross the blood-brain barrier. However, in some rare cases, injected GABA can reach certain areas of the brain that have no effective blood brain barrier.

Many manufacturers are offering GABA-based supplements claiming them to be able to cross the blood-brain barrier. We have the same situation here. NutraceuticsRx states that Phenibut can penetrate the BBB more efficient than the inhibitory neurotransmitter GABA. These are some bold claims that must be supported by relevant clinical studies. However, because of the extensive evidence that GABA is incapable of crossing the blood brain barrier at significant levels, these claims are likely untrue. The overall formula may be more efficient than the single amino acid, but it is important to support such statements with a strong, researched background.

Phenibut reviews posted online are positive. What is being reported includes: This has indeed offered me a good night’s, worry free sleep / This helps me cope with my social anxiety problems that I’ve been facing for years. The mood is better too.

Phenibut dosage depends on the condition for which it is used, body’s resistance to the active ingredients and physician’s recommendations. This is why you should consult with a healthcare provider, who will most likely start you on a smaller dose and increase it gradually until it produces the wanted effects. Some consumers have formulated Phenibut withdrawal concerns. Therefore dose should gradually be decreased in case you decide to interrupt treatment.

Pros & Cons

4) Phenibut: Pros and Cons

  • The active substance has been clinically studied (most of the research involves animal subjects)
  • The key ingredient has been used for decades as an anxyolitic agent with positive outcomes reported
  • The number of side effects is relatively low (as reported by consumers)


5) Phenibut Warnings and Precautions

  • This manufacturer of the formula does not have an official page (essential information about the formula is lacking)
  • There are no reviews available for consulting about this specific formula
  • Phenibut withdrawal effects are considered dangerous and should be treated with seriousness.


6) Phenibut Cost

One bottle of Phenibut contains 60 capsules, which should be enough for two months of treatment for the average user. You can also choose to buy Phenibut powder. In this case, each jar contains 100 grams of product. The recommended dose is one scoop per day, and each jar should contain up to 150 doses.

Phenibut is an average price supplement. It can be purchased directly from the manufacturer or various online retailers.

Suggested Use

7) Suggested Use

Phenibut side effects in humans are unknown due to lack of clinical research on humans. Excess amounts have been reported to cause dry-mouth and dizziness. Phenibut’s withdrawal symptoms are one of the main concerns with this product. These symptoms may manifest as seizures, insomnia, or increased hear rates. The recommendation is to gradually lower the doses and allow the body to readjust to the reduced doses. Phenibut recommended dosage is between 250 mg-1500mg.


8) Conclusion

Phenibut dietary supplement is based on the therapeutic benefits of a clinically researched substance. However, research on human subjects is still in its beginnings, so a complete list of drug interactions, side effects and other important things to consider when using this over-the counter formula has not been established.

Various manufacturers commercialize this formulation as Phenibut powder or capsules. Although both forms seem to be effective, the encapsulated form is claimed to lack the unpleasant taste of the powder. However, on the long run, the powder is the more affordable solution. As with all dietary supplement that don’t benefit of the FDA’s approval, our recommendation is to consult a healthcare practitioner before using the formula.

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