Phenibut is a GABAergic drug that is sometimes compared to benzodiazepines including gabapentin, diazepam and clonazepam.
GABA supplements, benzodiazepine drugs and phenibut are all used for anxiety, stress-relief, to promote restful sleep and to help people relax. Phenibut is also purported to have nootropic effects that can support focus and mental function.
These substances work by increasing activation of inhibitory GABA receptors in the brain, which are linked to feelings of calmness and sedative-like effects.
Although there are some similarities in their chemical structures and pharmacological effects, Phenibut, Benzodiazepines, and GABA are different compounds and can produce different results when taken by users.
Some users claim that phenibut is a better option for improving social behaviors and reducing feelings of inhibition. Others say that it does not impair cognitive function and has a mood-lifting effect, compared to a mood-dulling effect seen with benzos.
However, others claim that the effects of phenibut are not as consistent as prescription benzodiazepine drugs and there can be greater risk of misuse or side effects. Many users say they experience significantly worse withdrawal effects from this nootropic agent.
This article will review the differences between these substances, how they work, benefits and safety concerns.



- Powerful anxiolytic for stress reduction
- Stimulates GABA receptors & supports sleep
- Neuroprotective & supports cognitive function
Phenibut vs. Benzodiazepine vs. GABA
Related Topics
- What is Phenibut?
- User Review
- Benefits and Uses
- Dosage Recommendations
- Effects & Mechanisms of Action
- Experience Reports
- Anti-Anxiety Effects
- Using Phenibut for Sleep
- How to Take
- Negative Side Effects
- Withdrawal Dangers
- Risks with Alcohol Combination
- Comparison to Picamilon
- Buying Phenibut Guide
- Using Bulk Powder
- Primaforce Phenibut Review
- SNS Phenibut XT Review
Phenibut is a Russian-developed nootropic drug that was initially used to improve mental capacities during periods of extended stress. It also has anxiolytic (reduces anxiety) and mild sedative effects. [1]
Common uses for phenibut include improving concentration for long periods of study or work, increasing prosocial behavior, increasing energy, improving sleep, and reducing feelings of fear and anxiety.
Phenibut is associated with many effects that are also attributed to a class of drugs called benzodiazepines. These are drugs that are used clinically in the treatment of anxiety, insomnia and other mood disorders.
They work on similar pathways in the brain. Both phenibut and benzodiazepines are able to affect the activities of a brain-signaling chemical called GABA.
However, while they both increase activation of receptors for this neurotransmitter, it appears that phenibut and GABA work selectively on different subtypes of these receptors. Phenibut has stronger binding affinity for GABA(A) receptors while benzos have stronger binding affinity for GABA(B) receptors.
What is GABA?
Gamma-Aminobutyric Acid (C4H9NO2), also known as GABA, is the primary inhibitory neurotransmitter in the CNS (central nervous system).
As an inhibitory brain chemical, GABA works to “[filter] out irrelevant messages (static) by terminating signals from the excitatory neurotransmitters: glutamate, and its positive modulators epinephrine, norepinephrine, and PEA (phenylethylamine).” [2]
GABA receptors can be thought of as a system that regulates excitatory nerve signaling. Neurons that have receptors for this brain chemical are referred to as GABAergic neurons.
GABA works by reducing the likelihood that excitatory neurons in the brain will be activated or “turned on”. When released from a neuronal vesicle, it does the following:
- Binds to GABA-A and GABA-B receptors on the surfaces of neurons;
- Opens ion channels and allowing chloride ions to enter nerve cells;
- Reduces the likelihood of a neuronal action potential to be generated;
- Makes neurons less likely to fire;
The anxiolytic effects of GABA slow down neuronal firing in the brain, thereby reducing the transmission of excitatory signals. This make the brain less reactive to stress, fear, and anxiety.
The neurotransmitter GABA is produced endogenously from the GAD (glutamic acid decarboxylase) enzyme, glutamic acid, and pyridoxine (vitamin B6). However, some people may experience low levels of GABA synthesis or may have receptors that are less sensitive to this chemical messenger.
In these cases, anxiety disorders can develop as well as other problems that make it difficult to relax, focus and turn the brain “off” when preparing for bed. When anxiety is caused by problems in GABAergic regulation, use of a substance that artificially increases activation of GABA receptors may have therapeutic benefits.
GABA receptors as quite large compared to other neuronal receptors. Because of that, various other positive allosteric modulators and GABA agonists can bind to them.
Some substances that can bind to GABA receptors and induce anxiolytic effects include alcohol, barbiturates, baclofen, benzodiazepine drugs, phenibut and many others.

- Powerful anxiolytic for stress reduction
- Improves sleep and may reduce insomnia
- Neuroprotective and cardioprotective effects
What are Benzodiazepines?
Benzodiazepines are a class of psychoactive pharmaceuticals that are generally used for reducing anxiety. These drugs may also be prescribed by doctors for:
- Sedation prior to surgery or diagnostic procedures;
- Insomnia and other sleeping problems;
- Convulsions (seizures);
- Alcohol withdrawal;
- Panic attacks;
- Depression; [3]
All benzodiazepines have the same core chemical structure of a diazepine ring fused with a benzene Ring.
Some of the most common drugs in this category are Valium (diazepam), Xanax (alprazolam), Librium (chlordiazepoxide), Klonopin (clonazepam), and Neurontin (gabapentin) .
Benzodiazepines work by enhancing the effect of the neurotransmitter gamma-aminobutyric acid (GABA) in the brain. Specifically, these drugs increase the activity of this neurochemical at the GABA(A) receptor subtype.
This means that when you take drugs like Valium, Xanax or Klonopin, there is greater stimulation of GABA(A) receptors. These drugs are GABAergic because they positively mediate or facilitate activity at GABA receptors.
When these receptors are activated, the result is an anxiolytic (anti-anxiety) or sedative effect. Increased activation of GABA(A) receptors is also associated with hypnotic (sleep-inducing), anticonvulsant and muscle relaxant effects.
Benzodiazepines are considered relatively safe for short-term use. However, long-term use of these anti-anxiety drugs can cause tolerance, dependence, addiction, and withdrawal symptoms when trying to stop using them.
What is Phenibut?
Phenibut (C10H13NO2) is also known as beta-phenyl-gamma-aminobutyric acid.
It is a popular mood-enhancing “smart drug” that is considered a nootropic (enhances cognition), anxiolytic (reduces anxiety) and a sleep aid. [4]
Phenibut has a similar chemical structure to the natural GABA molecule, but with a synthetic phenyl ring added to it.
The Blood-Brain Barrier (BBB) is a filtering mechanism that separates brain tissue from circulating blood. It keeps harmful substances out of the blood that is sent to the brain and spinal cord tissue.
Synthetic GABA made in laboratories is not able to cross the BBB. However, the added phenyl ring of phenibut makes it able to cross the BBB.
This compound causes some effects that are similar to those of the natural GABA neurotransmitter. When it crosses the brain and binds to GABA receptors, it induces a strong anxiolytic effect. Some users say it increases their overall sense of well-being.
Unlike benzodiazepines, phenibut primarily acts on GABA(B). This nootropic is able to affect both GABA(A) and GABA(B) receptors but has stronger binding affinity for the B subtype.
Some research suggests that GABA(A) receptors mediate a faster anti-anxiety response than GABA(B) receptors. Alcohol and benzodiazepine drugs like Xanax and Klonopin activate GABA(A) receptors and induce a rapid effect.
Phenibut is said to induces a slower, longer-lasting anxiolytic effect by stimulating GABA(B) receptors. More research is needed to understand the different mechanisms of action involved as well as the different effects mediated by these two receptor classes.
While there are no research studies available to directly compare the effects of these types of GABAergic compounds, there are a large number of online user reviews that provide anecdotal evidence of some of the purported differences.
Phenibut’s anti-anxiety effects are described as “cleaner” and “brighter” compared to the “buzzed” or “dull” feeling of taking Xanax or Valium. Users also claim that Phenibut does not interfere with mental function, which is different than other sedatives.
Many describe their experience with Phenibut by saying it is similar to the positive mood associated with alcohol intoxication, but without adverse effects (lacking coordination, slurred speech, vomiting, etc.).

- Most effective supplements to improve mood
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Phenibut Safety
Phenibut powder and capsule are generally well-tolerated when taken in low doses by most healthy people.
However, various side effects are possible when used in excessive amounts or taken for long periods of time. Adverse reactions reported include headaches, sedation, irritability, nausea, anxiety, dizziness, and allergic reactions. [3]
High doses can cause loss of coordination, loss of balance, loss of consciousness, impaired judgement and respiratory depression. Some users report experiencing a Phenibut Hangover the next morning after they take this substance.
If you use this nootropic for long-term periods or in high doses, you should have your liver enzymes monitored. Risks for Eosinophilia and Fatty Liver Disease may be increased with chronic or heavy usage.
Do not take phenibut powder or crystals before operating heavy machinery or driving a vehicle. Using high dosages in combination with other sedatives or GABAergic drugs could result in an overdose or fatality.
Tolerance can develop quickly in some users with repeated use. Addiction or dependance is possible with long-term use.
Withdrawal symptoms can occur including:
- Auditory and/or visual hallucinations;
- Agitation, irritability, or anger;
- Severe rebound anxiety;
- Acute psychosis;
- Insomnia; [4]
Phenibut Addiction Treatment
Some people use phenibut to help them wean off of long-term benzodiazepine usage. This nootropic has also been studied in research trials to help patients overcome alcoholism.
However, it is also possible to become dependent on the effects of this GABAergic drug with overuse. People who take high doses or use it regularly for several days at a time have been known to experience withdrawal symptoms when they stop using it.
The San Diego Addiction Treatment Center states that withdrawal symptoms typically begin about 3-4 hours after the last dose taken. [5]
There are some reports of using baclofen (C10H12ClNO2) to treat phenibut addiction. However, baclofen may be even more addictive and also carries a risk of side effects.
Phenibut addiction is commonly-treated with small doses of other substances with mild-sedative effects. Some people use benzodiazepine drugs to help alleviate withdrawal symptoms.
Treatment should be conducted under the supervision of a medical professional. If you think you have developed signs of drug withdrawal or tolerance, it is important to seek medical attention and not to attempt to self-treat your condition.
Phenibut, Benzodiazepines, and GABA are similar with respect to their chemical structures and their pharmacological effects. To determine whether these substances are appropriate for you, it is important to consult with a doctor who is familiar with your health history.
- Corpina, D. How Phenibut and GABA Work. Accessed March 20, 2018
- Integrative Psychiatry. Natural GABA. Accessed March 20, 2018
- Wikipedia contributors. "Benzodiazepine." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 19 Mar. 2018. Web. 20 Mar. 2018 Nootropics Review Staff. PHENIBUT VS. BENZODIAZEPINE: EFFECTS, COMBOS, CROSS-TOLERANCE AND WITHDRAWAL. Accessed March 20, 2018
- San Diego Addiction Treatment Center Staff. Phenibut Abuse and Addiction Help. Accessed March 20, 2018