Researchers concerned about phenibut side effects should note that despite its well-documented anxiolytic and nootropic properties, phenibut poses certain risks to test subjects and must be administered with an appropriate level of caution.
This guide will draw upon relevant published data to provide an overview of known phenibut side effects, including phenibut’s short-term and long-term side effects, drug interactions, and overall safety profile. Researchers can also find a review of how phenibut has been dosed in clinical trials and suggestions for how it may be dosed in research settings moving forward.
As a bonus, researchers can also find our top recommendation for a reliable phenibut vendor that ships research-grade compounds worldwide.
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What Is Phenibut?
Phenibut is the generic name for 3-phenyl-4-aminobutyric acid, a neuropsychotropic drug that displays anxiolytic (anxiety-reducing) and nootropic (cognition enhancing) properties. First synthesized in the Soviet Union in the 1960s, phenibut is a mimetic of GABA (γ-aminobutyric acid) and is classified as a nootropic agent by Russian drug manufacturer Ozon .
Therapeutic benefits of phenibut
According to an Australian Therapeutic Goods Administration (TGA) report, Russia is currently the only country where phenibut is regulated , but it is also known to be marketed in CIS countries including Ukraine, Belarus, and Latvia.
Clinical trial data, the bulk of which is published in the Russian language, shows that phenibut has a direct effect on GABAergic receptors and facilitates nerve impulses mediated by GABA. Phenibut exhibits antiplatelet, antioxidant, and some anticonvulsant action without affecting choline and adrenergic receptors .
According to Ozon’s Instructions for Use for phenibut (“IFU”), the compound’s benefits include :
- Improving the functional state of the brain
- Increasing cerebral blood flow (the volumetric and linear velocity)
- Reducing vaso-vegetative symptoms (headaches, irritability, and sleep disturbances)
- Increasing physical and mental performance (attention span, memory, speed, and accuracy of sensory-motor responses)
- Reducing the manifestations of asthenia (by promoting interest and initiative)
- Reducing feelings of anxiety and tension
- Reducing the depressing effect of ethanol on the central nervous system (CNS)
According to the IFU, phenibut is indicated in Russia for treatment of the following :
- Asthenic and anxious-neurotic states
- Stuttering, enuresis, and tics (in children)
- Insomnia and nocturnal anxiety (in the elderly)
- Meniere's disease
- Prevention of motion sickness
- Alcohol withdrawal syndrome
- Relief of psychopathological and somatovegetative disorders
A review of published research shows that phenibut has been used to treat:
- Symptoms of anxiety in psychosomatic and neurotic patients 
- Symptoms related to anxiety spectrum disorders in patients with chronic cerebral ischemia (CCI) 
- Cognitive and emotional impairments in patients with “protracted anxiety-phobic disorders” 
Researchers curious about how phenibut may be dosed in an experimental setting can find information about dosing schedules in the following section.
How To Properly Dose Phenibut
Researchers curious about how phenibut may be administered should note that the majority of research involving this compound has been published in the Russian language. Phenibut is treated as a “new drug” in the U.S. and is a scheduled substance in Australia , Hungary , Italy , and France .
According to the IFU, phenibut is prescribed in two or three week courses and dosed at 250-500 mg three times per day, up to a maximum of 2,500 mg/day. The single maximum dose of phenibut is 750 mg.
The IFU document explains that certain conditions require different dosing protocols:
- Patients prescribed phenibut to treat alcohol withdrawal symptoms may be given 250-500 mg three times a day and one nightly dose of 750 mg.
- Patients taking phenibut for vestibular syndrome or Meniere's disease may take 250 mg three times a day for 14 days.
- Patients taking phenibut to prevent motion sickness or seasickness may take 250-500 mg once, approximately one hour before they travel.
As Russia and a handful of CIS states are the only countries where phenibut is marketed, there is little additional evidence regarding how this compound may be dosed in an experimental or therapeutic setting. According to the Australian TGA’s rationale for scheduling phenibut as a controlled substance, there is “strong evidence” that phenibut is marketed online as a dietary supplement and is used as a recreational drug . A review of phenibut’s recreational use by Owen et al. concluded that this compound is “taken orally at an average dose of 2.4 g” .
In the following section, we will outline phenibut’s short-term side effects.
Phenibut Side Effects | Short-Term
According to the IFU, phenibut has been linked to the following short-term side effects in subjects :
- Increased irritability
- Allergic reactions
Due to phenibut’s mechanism of action, it should not be administered to subjects who are pregnant, breastfeeding, hypersensitive, or suffering from gastrointestinal and/or liver issues .
Subjects who exceed the maximum dose (as outlined in the previous section) may experience the following short-term symptoms of overdose :
- Increased severity of side effects
- Severe drowsiness
Phenibut Side Effects | Long-Term
According to the IFU, the following side effects have been linked to long-term phenibut use :
- Fatty degeneration of the liver (when intake exceeds 7 g)
- Decreased blood pressure
- Impaired renal function
The IFU advises phenibut subjects to refrain from potentially hazardous activities requiring increased attention, while cautioning physicians that with prolonged use, it is necessary (to) periodically monitor indicators (such as) liver and peripheral blood function .
The recommended treatment for impaired renal function resulting from phenibut use is gastric lavage, intake of activated charcoal, and symptomatic therapy .
Further review of the medical literature shows that phenibut use has been linked to the following side effects:
- Rapid development of tolerance 
- Physical and psychological dependence 
- Acute withdrawal symptoms requiring hospitalization 
According to the Australian TGA, phenibut presents a “significant risk of harm, including overdose”  and may cause several long-term side effects including:
- CNS depression
In the following section, we will examine phenibut’s known interactions with prescription drugs.
As a GABA-mimetic, phenibut should not be administered alongside other substances that work along a similar pathway. This would include anxiolytics, anticonvulsants, or antipsychotic medications, alcohol, barbiturates, opioids, sedatives, or benzodiazepines. The IFU document states that phenibut may lengthen and enhance the effect of sleeping pills, narcotic analgesics, antipsychotics, antiparkinsonian, and antiepileptic drugs .
According to Drugbank, phenibut has 515 known drug interactions . The majority of these interactions relate to phenibut’s potential to increase the risk and/or severity of side effects and/or CNS depressant activities of the drugs with which it is coadministered. Researchers interested in researching phenibut side effects should carefully screen for these interactions before administering this compound to test subjects.
Is Phenibut Safe?
Researchers curious about whether phenibut is safe should note that it has not been approved for use outside of Russia and several CIS countries (including Ukraine, Belarus, and Latvia), and that it is a controlled substance in Australia , Hungary , Italy , and France . There are numerous reports of phenibut use leading to dependence issues [2, 10] and acute withdrawal symptoms .
In the United States, phenibut is classified as a “New Drug” under the U.S. Federal Food, Drug, and Cosmetic Act (FD&C Act) and thus cannot be sold as a dietary supplement. As noted by Graves et al., a total of 1,320 calls were made to U.S. poison centers for phenibut exposure from 2009-2019, and “among exposures in which phenibut was the only drug or agent involved, 10.2% were associated with major effects, including one death” .
Where to Buy Phenibut Online? | 2022 Guide
For researchers curious about where to buy phenibut online, this is the section where we will share our top vendor. Finding a reputable vendor that can reliably ship research-grade phenibut worldwide is no easy task. While there are many online vendors who claim to ship phenibut worldwide, in practice, few can actually make good on their promises and reliably deliver phenibut within a reasonable time frame.
To assist researchers, our team has placed test purchases from multiple online vendors and judged them according to the speed and reliability of their delivery, the quality of the products, and other factors such as their website and customer service.
Overall, we determined that Science.bio is currently the best place to buy phenibut online in 2022 as it has the best prices, the fastest shipping times, and the best customer service. While we’re certain that researchers will have a positive experience buying phenibut from Science.bio, we recognize that this compound is a controlled substance in several countries. Therefore, we still advise researchers to do due diligence and check local laws before placing an order.
Here are a few of the reasons why we feel Science.bio is the No. 1 phenibut vendor for 2022 and beyond:
- Third-Party Testing: To ensure transparency, Science.bio has every phenibut batch tested and coded by an independent lab prior to listing them for sale. All lab reports are published on its website. This lets researchers see the exact quality and purity of the phenibut they are buying before they place an order.
- Competitive Pricing: Science.bio is ideal for researchers working to a tight budget. Placing a large order of phenibut (200+ vials) can see the price per unit drop to just $10.49. This represents great value for money and is one of the lowest prices our team has ever seen.
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Side Effects of Phenibut | The Verdict
Researchers curious about phenibut’s side effects should note that comparatively little is known about this compound’s short-term and long-term side effects. While it has been linked to a number of concerning incidents such as dependence, withdrawal, and at least one fatality, there remain numerous areas where further research is warranted. Researchers interested in experimenting with phenibut should exercise appropriate levels of care and caution before administering it to test subjects.
We strongly endorse Science.bio to any researcher looking to run a study on phenibut.