What Is Phenibut? An Overview of Benefits, Effects, Stacks and Dosages of This Powerful Russian Nootropic For Anxiety

Updated September 10, 2018

When it comes to a nootropic supplement for anxiety, few rival the popularity and efficacy of Phenibut. Created in Russia in the 1960s, this drug is still used there for the treatment of depression, asthenia (lack of energy and/or weakness), anxiety, insomnia, and fear. (1)

As a nootropic, it helps to promote a calm, positive mood, with a slight cognitive boost at low doses. While its effects on cognition are not as strong as those of many common nootropic supplements, it does exhibit some cognition enhancing effects.

When taken in higher doses, many report feelings similar to Xanax or alcohol, feeling calm and slightly buzzed, but without a detrimental effect on focus and motivation.

Thanks to its potent anxiolytic effects, Phenibut is often part of nootropic stacks. By pairing it with nootropics known to improve memory and brain health, neurohackers are able to promote a relaxed learning state. This is particularly popular with students during exam time.

Where Is Phenibut Legal?

Phenibut is legal in the US and Canada, where it’s not classified as a controlled substance and can be purchased without a prescription. In the UK it is unlicensed and unregulated, making it legal to possess but not legal to sell. This makes it difficult to find, however you can purchase from outside of the country and bring it in if you’re determined to give it a try. In Australia it’s categorized as a Schedule 9 prohibited substance, making it illegal to sell or possess.

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Mechanisms of Action

A clue as to how this compound works is in its chemical name: gamma-aminobutyric acid, also known as GABA. GABA is our primary inhibitory neurotransmitter, helping to promote a calm mood, fighting anxiety, stress, and insomnia.

Phenibut is a phenylated derivative of GABA. In supplement form, GABA is unable to successfully penetrate the blood-brain barrier. The unique chemical composition of Phenibut allows it to cross this protective barrier and exhibit calming effects on our neurons (brain cells).

Once inside the brain, it works as a GABA-mimetic, acting mainly on GABA(B) receptors, with some action of GABA(A) receptors. (1) It also opposes the action of Beta-phenylethylamine, or PEA, an endogenous chemical that is involved in anxiety.

Benefits, Effects, & Uses

Anxiety and Aggression

While user reviews on the benefits of Phenibut as an anxiety-fighting compound are seemingly endless, there have not been many studies to evaluate this effect. Presently there have been animal studies that have found this drug to decrease anxiety, fear, and aggression. (3,4,5)


User reviews report changes in appetite when using this nootropic. Studies suggest that withdrawal symptoms from this compound may lead to reduced appetite, however no studies have been done to confirm if this carries over to when using this compound. (1)

Studies do support the role of GABA on appetite. GABA receptors are found not only throughout the central nervous system, but also in the gastrointestinal tract. (13) Some users report increased appetite when taking low doses, and studies suggest that GABA(B) agonists, such as Phenibut, may actually increase appetite.

Cognitive Benefits: Learning, Memory, and Neuroprotection

Multiple animal studies have found nootropic benefits of Phenibut. In one study on rabbits, supplementation in early life was found to accelerate defensive reflex and conditioned inhibition development – this suggests that this drug may help to improve memory storage and learning. (10)

Other animal studies found this nootropic to exhibit anti-amnesic effects, neuroprotective properties, and reduced cognitive injury from stroke. (9,11)


Thanks to its calming and slightly sedative effects, many who use this drug for anxiety report benefits with sleep and insomnia. This effect is likely to be more pronounced in those suffering from anxiety-induced insomnia.

Cardiovascular Protection

Animal studies have found this drug to protect the heart during periods of stress, improve heart rhythm, and protect from cardiac damage caused by acute alcohol intoxication. (6,7,8)

Strengthens the Immune System

Chronic stress and anxiety are excitatory states that have been found to lead to a weakened immune system. It doesn’t come as much of a surprise that Phenibut, likely through its ability to calm excitatory responses in the body, has been found to restore the immune system of mice. (12)

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Other Supplements Like Phenibut

Many neurohackers wonder what the best substitute for Phenibut is. Whether this is due to a lack of availability of Phenibut in your country, a desire to cycle it with another anxiolytic to avoid tolerance or withdrawal, or lack of desired effects with supplementation, there are many viable options.

Here is a list of alternate anxiety-fighting nootropics:

  1. Picamilon: Fights stress and anxiety while increasing concentration, mental energy, and cognitive function. Chemically it is niacin (a B-vitamin) plus GABA, and it works largely through its impact on the GABAergic system
  2. Aniracetam: This member of the racetam family of nootropics harnesses the impressive benefits for memory, learning, focus, and brain health that racetams are known for, with additional anxiolytic properties. It is known to help reduce stress and depression, promoting a positive mood.
  3. L-Theanine: Green tea is known for its ability to boost energy and concentration while supporting a calm mood. These benefits are largely thanks to the amino acid L-Theanine, which is found in high concentrations in green tea.
  4. Ashwagandha: This natural adaptogen has been shown in numerous studies to be quite effective at reducing stress in humans.
  5. Rhodiola Rosea: Another adaptogen, Rhodiola Rosea is able to fight all three types of stress: emotional, physiological, and cognitive. This means that you may experience less stress while also healing faster from physical stressors, such as exercise or injury.
  6. Mind Lab Pro: If you are looking for a nootropic supplement that is a quality mixture of mood-boosting and cognition-promoting compounds, Mind Lab Pro is one of the best on the market. Every ingredient is natural, leaving you with a noticeably powerful nootropic when it comes to mood, anxiety, focus, memory, and learning, with very few side effects.


Phenibut vs GABA

GABA is a neurotransmitter produced endogenously in the human body. Synthetic GABA supplements do exist with purported benefits of promoting relaxation and a positive mood.

Phenibut acts mainly through mimicking GABA in the body and mind – the benefit with Phenibut over synthetic GABA supplements is that it is more capable of crossing over the blood-brain barrier, and thus its benefits on mood and cognition are greater than those of synthetic GABA.

L-Theanine vs Phenibut

L-Theanine is a natural compound found in high levels in green tea. Rather than mimicking GABA, it naturally increases the levels of GABA and other neurotransmitters in the brain.

Additionally, it alters brain waves, resulting in increased alpha and theta brain waves. These brain waves are associated with focus, relaxation, and creativity. It is also known to inhibit the release of glutamate, the excitatory neurotransmitter that can lead to stress and anxiety.

When it comes to anxiety relief, most people find Phenibut more powerful, however this comes with the risks of tolerance and
withdrawal. If you are looking for a more subtle anxiolytic effect paired with a natural well-rounded nootropic, L-Theanine is a good option.

Phenylethylamine HCl vs Phenibut

Phenylethylamine HCl, also known as PEA, is a compound that is produced endogenously in humans. It is known to help with mood, attention, energy, memory, and weight loss. It works through increasing the release of dopamine, norepinephrine, b-endorphin, and acetylcholine.

If you are looking for a nootropic mainly to fight anxiety and stress, Phenibut is the best option. PEA is better for overall improvement of mood outside of anxiety disorders, along with increasing learning ability and focus

Piracetam vs Phenibut

Piracetam is the first member of the racetam family, and the first nootropic compound. Chemically, it is a synthetic derivative of GABA that is mainly used for its ability to improve memory. It is well-studied and considered safe when taken at recommended doses.

Unlike Phenibut, Piracetam is not particularly powerful at relieving anxiety.

Noofen vs Phenibut

Noofen is simply the brand-name for Phenibut sold in certain countries, including Georgia and Latvia.

Phenibut FAA vs HCl

There are two versions of this supplement to choose from: Phenibut Hydrochloride (Phenibut HCl) or Phenibut Free Amino Acid (Phenibut FAA). Phenibut HCl is the most widely used form of this nootropic, and is best suited for taking in capsule or tablet form.

Phenibut FAA is best for sublingual use, and is gaining popularity among neurohackers. Many report this form to be around three times as potent and bioavailable, so you may need a smaller dose of FAA in comparison to HCl. This form is more expensive than the HCl form.

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Best Phenibut Stacks

Phenibut is one of the most commonly stacked nootropics – this is largely due to its providing a very powerful singular benefit, rather than a balanced array of benefits. By stacking this drug with other nootropics, you can tailor your anti-anxiety stack to include additional health effects.

Sulbutiamine and Phenibut

Sulbutiamine offers a subtle boost in energy, which stacks well with Phenibut for the goal of boosting motivation and energy while simultaneously promoting a calm and relaxed mood.

Phenibut and Kratom

If you suffer from debilitating social anxiety, this combination may help you find relief. Kratom and Phenibut are both powerful anxiolytics. This stack is best for those suffering from anxiety disorders – it is not your typical mood-boosting nootropic stack.

Aniracetam and Phenibut

Users report a synergy between these two anxiolytic nootropic compounds. This isn’t too surprising as their mechanisms of action are different, so they work on reducing stress through different paths. As Aniracetam does not lead to withdrawal, it can be helpful to stack with Phenibut, which you should cycle regularly.

Phenibut and L-Theanine Together

L-Theanine is a compound found in green tea that is touted for its health benefits. This compound is frequently stacked with caffeine to promote motivation and focus without the jitters of too much caffeine on its own. Both L-Theanine and Phenibut are known for their anxiolytic properties, which work synergistically thanks to different ways that they exert their benefits in the body. Stack all three to experience a calm, motivated concentration.

Phenibut and Piracetam

Piracetam and Phenibut are often stacked to provide a well-rounded nootropic experience. The Piracetam offers the brain health, memory, and learning boost while Phenibut works to reduce anxiety and stress.

Noopept and Phenibut

Just as Phenibut is one of the most potent anxiolytics, Noopept is one of the most powerful nootropics when it comes to memory, learning, and brain health. Combining these two can be good for an experienced neurohacker who is looking to notice very dramatic changes in cognition and mood.

Phenibut and Choline

Phenibut and choline are most frequently stacked together to promote athletic performance, thanks to its combined effect of reducing stress and supporting human growth hormone levels.

Phenibut and Phenylethylamine

Some users report Phenibut to help reduce the anxiety experienced when supplementing with Phenylethylamine (PEA). Outside of this use, it is not too common to stack these two nootropics together.

Dosage Guide: How to Take Phenibut Safely

While there is no recommended dosage with this compound thanks to insufficient human studies, users have experimented enough to provide a good guideline. Most users will take anywhere from 250 to 1,000 mg/day – as with most other nootropics, it is advised to start at a low dose and work your way up, until you find the right dosage for you.

Is Phenibut water soluble?

Phenibut is water soluble, so you do not need to take it with food. Taking it on an empty stomach is fine. If using the powder, mixing it with juice helps to mask the bitter taste. In order to avoid tolerance, you will either want to only take it when you need it, or cycle, taking up to a few days on and a couple of days off.

How long does Phenibut take to kick in?

Most users will start to feel it kick in slightly around 30 minutes post consumption, with the effects slowly building and lasting around 12 hours.

Half Life: How long does Phenibut stay in your system?

With a half-life of roughly 5 hours and total elimination from your system not until 24 hours, it is important not to take too much of this compound in a 24 hour period.

Because of the moderate half-life, some users will break their dosage up into two doses during the day, however many others report still feeling an “afterglow” the following day from one dose early in the morning. If you’re wondering when to take it, most users will dose one time in the morning, and some will include a second dose around lunchtime.

Be careful when using this drug for sleep. The dosage for sleep is the same as for anxiolytic purposes, however it should not be used every day because of tolerance risk.

Does Phenibut show up on a drug test?

Phenibut does not show up on a standard drug test.

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Things to Consider Before You Take Phenibut

Even though Phenibut is used successfully in nootropic stacks, you need to be careful of dangerous combinations. Combining it with certain anxiolytics or alcohol is not recommended. There are other side effects that you will want to be careful of, including the risk of tolerance and withdrawal.

While many have found success with this nootropic, there are others who have had different experiences. User reviews of Phenibut can help you learn what to expect, along with experiences of a variety of Phenibut stacks.

Be sure to buy Phenibut supplements only through a reputable source, as some products on the market may not be what they claim. Pure Nootropics and Nootropics Depot are two online vendors that offer quality products and competitive prices.


  1. Phenibut Dependence and Management of Withdrawal: Emerging Nootropics of Abuse https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5952553/
  2. Phenibut: A tranquilizer and nootropic drug https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1527-3458.2001.tb00211.x
  3. Effect of GABA receptor phenibut on behavior of rabbits in the negative emotional situation https://www.ncbi.nlm.nih.gov/pubmed/17944107
  4. Influence of GABA agonist phenibut on the neuronal activity and interaction in hippocampus and neocortex in emotionally negative situations https://www.ncbi.nlm.nih.gov/pubmed/19899708
  5. Effect of phenibut and citrocard on non-competitive and competitive behavior during provoked aggression in animals https://www.ncbi.nlm.nih.gov/pubmed/26033589
  6. NO-dependent mechanism of the cardioprotective action of phenibut on stress-induced violation of contractile function of the heart https://www.ncbi.nlm.nih.gov/pubmed/27017698
  7. Cardioprotective effect of GABA derivatives in acute alcohol intoxication https://www.ncbi.nlm.nih.gov/pubmed/16995433
  8. Antiarrhythmic properties of GABA and GABA-ergic system activators https://www.ncbi.nlm.nih.gov/pubmed/12025796
  9. Effect of phenibut and its composition with nicotinic acid on hemostasis in rats with brain ischemia https://www.ncbi.nlm.nih.gov/pubmed/22702103
  10. The effects of agonists of ionotropic GABA(A) and metabotropic GABA(B) receptors on learning https://www.ncbi.nlm.nih.gov/pubmed/19476215
  11. Comparison of nootropic and neuroprotective features… https://www.ncbi.nlm.nih.gov/pubmed/26906198
  12. Changes in the psycho-emotional state under conditions of suppressed immunogenesis https://www.ncbi.nlm.nih.gov/pubmed/20432718
  13. A gut feeling about GABA: Focus on GABA(B) Receptors https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3153004/

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