Issac Thorne

Last Updated February 13, 2022

Phenibut is taking off among nootropic researchers. Better known for its anti-anxiety effects, the compound is increasingly studied for its role in cognitive enhancement.

But if you’re a phenibut researcher and test subject, make sure you’re aware of the safety concerns associated with phenibut—and what happens if too much is ingested.

Is phenibut overdose a legitimate concern?

In a word, yes. Phenibut overdose can cause serious adverse effects, and this can include death.

By taking proper precautions and designing prudent dosing schedules, researchers can drastically reduce the likelihood of a phenibut overdose in their human subjects. Keep reading as we break down the relevant literature.

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What is Phenibut?

Phenibut is a neuropsychotropic drug that’s used for its anxiolytic and nootropic properties. In countries including Russia and Latvia, it’s a prescription medication used to treat or relieve conditions like anxiety, insomnia, and PTSD [1].

Phenibut is chemically similar to a neurotransmitter called GABA, which stands for gamma-Aminobutyric acid [2]. GABA, like all neurotransmitters, helps the brain send messages throughout the nervous system. Specifically, GABA is an inhibitory neurotransmitter [3]. It helps calm down the neurons and lower their excitability, getting them to send fewer signals.

When GABA attaches to your body’s GABA receptors, you may experience calmness and an ability to cope with anxiety, stress, and fear.

Phenibut binds to GABA receptors, and therefore can produce the effects as GABA itself, reducing neuronal excitation. It’s no coincidence then, that phenibut is prescribed in certain countries to aid sleep, boost mood, and reduce anxiety in patients [1, 4].

Note that while phenibut is available to qualified researchers in most countries, including the United States, it has not been reviewed or approved by the FDA for any use.


Can You Overdose on Phenibut?

In the United States at least, there has been at least one reported death from phenibut-only consumption [5]. The circumstances surrounding that death are not known; all we know is that the deceased individual had taken phenibut, and that no other substance was involved. In general, however, fatality from phenibut overdose is rare [1].

One basic precaution for avoiding overdose is simply to avoid taking more than the maximum recommended dose of a substance.

We have articles on calculating an appropriate phenibut dosage and taking phenibut properly, so check those out to better determine an appropriate dose for your research participants.

Here’s a summary of the dosing guidelines related in those articles:

  • Standard phenibut dose: 250 mg to 500 mg, in a single dose, one day per week.
  • Maximum single phenibut dose: The most one should take in a single dose is 750 mg [4].
  • Maximum daily phenibut dose: The most one should take in a single day is 2.5 g [4].
  • Maximum phenibut doses per week: Subjects should not take phenibut more than twice a week to avoid dependence.

Even if you fully intend to work within these guidelines, it’s prudent to start test subjects off on even smaller doses to gauge an initial response.

Phenibut Overdose Symptoms

There are a number of symptoms associated with phenibut overdose. We've reviewed the medical literature on the results of phenibut overdose, and here are a few summaries of the overdose symptoms that have been reported:

  • A 25-year-old man was admitted to a hospital having overdosed on phenibut. The case report authors could not determine how much phenibut he had taken. The patient’s symptoms included decreased consciousness, erratic behavior, and confusion. Eventually, he regained consciousness and made a full recovery [6].
  • Another 25-year-old man was found unconscious following a phenibut overdose. He had taken three grams of phenibut a day for four days in a row, in addition to potentially high quantities of alcohol—the man had a history of alcohol dependence. The patient regained consciousness seven hours from admission and made a full recovery [7].
  • One 38-year-old man experienced excited delirium after combining phenibut with cannabis and alcohol. It is unclear how much phenibut the man ingested, though his plasma phenibut concentration was 36.5 μg/ml. He made a full recovery [8].
  • One article that reports on six different cases of phenibut overdose found that overdose symptoms included: agitation (in all 6 patients), confusion (5), drowsiness (4), hypertension (3), tachycardia (2), muscle rigidity (2), hallucinations (1), nausea (1), anxiety (1), insomnia (1) and vomiting (1). Three of the patients had taken a total of nine grams of phenibut or more [9].
  • One individual took between 7.5 and 10 grams of phenibut in an attempted suicide. The patient had symptoms of agitation and abdominal pain, but was treated shortly after ingestion of the excessive dose [10].
  • Yet another individual took between 10 and 15 grams of phenibut each day for three months. His symptoms upon admission were tremors and dysuria [10].

Together, these cases show that phenibut overdose can lead to severe symptoms requiring hospital admission. It appears from the literature that the vast majority of phenibut overdose patients are able to make a full recovery after receiving proper treatment.

Phenibut overdose symptoms include:

  • Decreased consciousness
  • Erratic behavior
  • Confusion
  • Anxiety
  • Agitation
  • Delirium
  • Hypertension
  • Tachycardia
  • Muscle rigidity and tremors
  • Hallucinations
  • Nausea and vomiting
  • Insomnia
  • Abdominal pain
  • Psychosis [11]

If you or your study participant starts experiencing any or a combination of these symptoms, or if you or your study participant may have ingested an excessive amount of phenibut, seek urgent medical care.

Phenibut Side Effects

Could an individual experience phenibut side effects even at an appropriate dose?

Yes, phenibut does have the potential to cause some side effects, and these include:

  • Irritability
  • Drowsiness
  • Sedation
  • Nausea
  • Headache
  • Loss of balance
  • Hangover-like symptoms
  • Motor incoordination

The likelihood of experiencing side effects generally increases as you raise the dose. We reiterate the importance of establishing a minimum effective dose as a way to not only avoid overdosing, but side effects in general.

is phenibut safe

Is Phenibut Addictive?

Yes, phenibut can be addictive.

Addiction with phenibut happens when an individual starts to form a physical dependence on the drug. This is where the body becomes accustomed to excess GABA receptor excitation and tries to bring that activity back down to normal. In so doing, the body may reduce its own GABA production or even start to reduce the number of receptors.

In such cases, the phenibut subject will feel like they need more phenibut to get the same effect as before. They may even start needing phenibut just to function normally. And then when they stop taking it, they may end up getting massive phenibut withdrawal effects.

The task is to prevent addiction from happening in the first place.

One precaution when selecting phenibut study participants is to screen candidates for past substance abuse issues and a propensity for addiction.

How Often Can You Take Phenibut?

To avoid addiction in phenibut subjects, researchers are advised to avoid facilitating overly frequent use. A conservative rule for otherwise healthy subjects would be one to two days per week maximum.

Less than that is, of course, better from a risk mitigation standpoint.

Researchers may also consider advising their subjects to cycle off phenibut following a period of use. By discontinuing phenibut use for a period of time, subjects may be at lower risk for developing phenibut dependence.

Benefits of Phenibut

But why study phenibut in the first place?

There are a variety of potential phenibut benefits, including:

  • Cognitive enhancement and creativity. This includes increases in attention and memory, as found in a small sample of participants with anxiety-phobic disorders [12].
  • Reduces anxiety. Phenibut is prescribed as an anxiety medication in countries like Russia [13].
  • Improves sleep. Where it’s a prescription drug, phenibut is used to treat insomnia and other sleep disorders [1]. One study of individuals with alcohol withdrawal found that phenibut helped increase the length of two phases of sleep [14].
  • Improves energy. Phenibut has been found to beat fatigue. In a small study on youth with neurasthenia and residual asthenia, phenibut was found to improve symptoms of fatigue [15].
  • Improves socialization and emotional intelligence. At least one study on patients with protracted anxiety-phobic disorders found that phenibut can help boost emotional intelligence [12].

Where to Buy Phenibut Online? | 2022 Guide

Phenibut is a prescription drug in countries like Russia. But in most places, including in the United States, it is an uncontrolled research chemical that qualified researchers are free to buy online.

The trick to find a legitimate phenibut vendor. Since the research nootropics space is largely unregulated, you run the risk of scams or obtaining a low-quality product.

We have tried a variety of vendors and our favorite is none other than

Why are they so great? There are several reasons:

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  • Great prices. has reasonable prices for such a high-quality phenibut product. Currently, a 50g jar of phenibut HCL powder costs $24.99, while the 50g FAA powder is priced at $29.99.
  • Return policy. Buying things online always takes a bit of faith. But you can buy with confidence at thanks to its consumer-friendly return policy and product guarantees. If there’s ever an issue, you can count on them to make it right.
  • Fantastic support. has invested in their support team, which is fully dedicated and ready to answer all of your questions. If you have any issue whatsoever, just give them a call or send an email and they'll sort it out.

Stick with and you won't have any issues getting high-quality phenibut safely delivered to your research lab.

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Phenibut Overdose | Verdict

Is phenibut dangerous?

Like many substances, it certainly can be. In the United States, there has been at least one fatality linked to phenibut overdose. Thankfully, however, most phenibut overdoses documented in the literature have resulted in swift recoveries.

Overdose does not typically happen by accident. It tends to be the result of a recreational user or patient taking more—often, significantly more—phenibut than recommended or directed.

Prudent dosing is the key to overdose prevention: a single phenibut dose should not exceed 750 milligrams, while the total ingested in one day should not exceed 2.5 grams.




  1. Lapin I. (2001). Phenibut (beta-phenyl-GABA): a tranquilizer and nootropic drug. CNS drug reviews, 7(4), 471–481. doi:10.1111/j.1527-3458.2001.tb00211.x
  2. Zvejniece, L., Vavers, E., Svalbe, B., Veinberg, G., Rizhanova, K., Liepins, V., … & Dambrova, M. (2015). R-phenibut binds to the α2–δ subunit of voltage-dependent calcium channels and exerts gabapentin-like anti-nociceptive effects. Pharmacology Biochemistry and Behavior, 137, 23-29.
  3. Li, K., & Xu, E. (2008). The role and the mechanism of γ-aminobutyric acid during central nervous system development. Neuroscience Bulletin, 24(3), 195.
  4. Ozon Pharm (n.d.), Fenibut (PDF). [In Russian].
  5. CDC (2020). Notes from the Field: Phenibut Exposures Reported to Poison Centers — United States, 2009–2019.
  6. Sankary, S., Canino, P., & Jackson, J. (2017). Phenibut overdose. The American journal of emergency medicine, 35(3), 516-e1.
  7. O'Connell, C. W., Schneir, A. B., Hwang, J. Q., & Cantrell, F. L. (2014). Phenibut, the appearance of another potentially dangerous product in the United States. The American journal of medicine, 127(8), e3-e4.
  8. Downes, M. A., Berling, I. L., Mostafa, A., Grice, J., Roberts, M. S., & Isbister, G. K. (2015). Acute behavioural disturbance associated with phenibut purchased via an internet supplier. Clinical toxicology, 53(7), 636-638.
  9. Goertemoeller, S. (2015). Phenibut overdose. Reactions, 1571, 193-3.
  10. Koppen, A. (2015). Phenibut overdose. Reactions, 1571, 192-3.
  11. Högberg, L., Szabó, I., & Ruusa, J. (2013). Psychotic symptoms during phenibut (beta-phenyl-gamma-aminobutyric acid) withdrawal. Journal of Substance Use, 18(4), 335-338.
  12. Chutko, L. S., Surushkina, S. I., Iakovenko, E. A., Nikishena, I. S., Anisimova, T. I., & Bondarchuk, I. L. (2014). Cognitive and emotional impairments in patients with protracted anxiety-phobic disorders. Therapeutic archive, 86(12), 61-65.
  13. Owen, D. R., Wood, D. M., Archer, J. R., & Dargan, P. I. (2016). Phenibut (4‐amino‐3‐phenyl‐butyric acid): Availability, prevalence of use, desired effects and acute toxicity. Drug and alcohol review, 35(5), 591-596.
  14. Danilin, V. P., Krylov, E. N., AIu, M., & Rait, M. L. (1986). Effect of fenibut on the nocturnal sleep of patients with the alcoholic abstinence syndrome. Zhurnal nevropatologii i psikhiatrii imeni SS Korsakova (Moscow, Russia: 1952), 86(2), 251-254.
  15. Chutko, L. S., Surushkina, S. I., Nikishena, I. S., Iakovenko, E. A., Anisimova, T. I., Bondarchuk, I. L., & Sergeev, A. V. (2014). Asthenic disorders in children and their differentiated treatment. Zhurnal nevrologii i psikhiatrii imeni SS Korsakova, 114(12), 99-103.

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