Phenibut Side Effects : Understand The Risks

Phenibut is a popular mood-enhancing nootropic that interacts with GABA receptors in the brain to produce anxiolytic effects.

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What you will learn on this page​

  • Compound overview
  • How to use phenibut
  • Potential risks
  • General guidelines


Phenibut (also called Noofen) has been around for decades but is still rather unknown to the bulk of consumers.  It is essentially a legal form of anti-anxiety medication that can be purchased without a prescription in many countries today.  It is often labeled as a GABAergic compound because it works by affecting a part of your brain called the GABA receptors.  If you are unfamiliar with this product, then consider educating yourself with our extensive guide to phenibut.

How Phenibut Is Used

Phenibut is sold in capsule or powder form with a recommended dosage of 200 - 1000 mg to treat symptoms of anxiety and depression.  Doses of up to 2 grams are often tolerated and can be used as an effective sleep aid. Of course, these are just average serving sizes across a spectrum of users -- everyone will react differently, so it is important to experiment to see what is right for you.  For new users, starting with a lower dose is always recommended.  Further guidance about dosages can be found in out article about phenibut dosage.

Based on consumer reviews, it appears that the primary uses of phenibut are for anxiety, especially social anxiety, and better sleep quality.  Fringe use cases also exist as a post workout supplementation and mood enhancer.  This compound is generally considered to be safe, but the threat of negative side effects is also very real.  Undesirable effects are usually the result of over-consumption and/or overuse.

Due to the nature of the product, phenibut can not be taken habitually and it is also very dose-sensitive.  With these things in mind, we will now transition this article to discuss the possible side effects of phenibut.  To further your understanding, please enjoy the below video...​

Possible Side Effects of Phenibut

It's very important to be aware of what goes into your body, especially something that affects the central nervous system such as phenibut does. Since most nootropics are generally safe and non-toxic, some people don’t do enough research beyond the promised benefits.  They may come to the conclusion that an over-the-counter supplement has no risks.

This is not a good mindset to have, and has surely gotten people into trouble.  By understanding the risks, you will be able to use phenibut in a way that is both safe and beneficial.  

The primary cause of most phenibut side effects can be categorized into three groups of people.  

  • Those who take entirely too much phenibut
  • Those who do not properly cycle their usage
  • Those who mix phenibut with other drugs

These irresponsible behaviors can result in some pretty nasty side effects such as ...

  • Nausea
  • Headaches
  • Dizziness
  • Fatigue
  • Blackouts
  • Shallow breathing
  • Vomiting
  • Insomnia
  • Psychosis
  • Dependence
  • Withdrawal
  • Irritability

Note:  These are not all common reactions and most are completely avoidable.

Taking Too Much

As we touched on earlier, phenibut is a very potent substance that has inherit differences according to how much is taken.  At low doses, it can be somewhat stimulating and good for morale.  At higher doses, it can feel more like a sedative and provide assistance in sleep.  At extremely high doses, it can produce euphoria and negative side effects such as those listed above.

Watching how much phenibut you consume is very important.  While rare, it is possible to overdose on phenibut.  To ensure this doesn't happen to you, you should never take more than the recommended amount and always start off with the lowest effective dose.  You don't want to find yourself in the ER because you irresponsibly swallowed 6 grams on your first try!

Not Cycling

Cycling is an important aspect of a phenibut regiment and a smart way to avoid any unpleasant reactions due to over-use.  Cycling simply refers to taking time off between your doses so your body doesn't become dependent on the drug.

​We recommend allowing at least 3 days between each phenibut dose to ensure safety.  This equates to no more than twice a week.  Some people will take it more often while others may only be able to use phenibut a couple times a month before they experience diminishing returns.  

As always, use caution and your better judgement in determining what is right for you.  If, for instance, you notice that you are no longer getting the effects that you desire and are considering upping your dosage --- STOP! Take some time off.  This could be a sign that your body is becoming tolerant to phenibut and could benefit from a break.

Mixing Phenibut With Other Substances

This could possibly be the most dangerous cause of negative side effects.  A common mistake made by people is thinking that it is okay to drink alcohol or use other drugs while under the influence of phenibut.  This is a very bad idea.

  • Food For Thought...

If you're taking phenibut in an attempt to get high or intoxicated then you may want to rethink your game plan.  Nootropics are here to help us...not hurt us.

As you know, phenibut is a GABAergic compound, but so is alcohol and benzodiazepines such as valium and xanaz.  This means that this group of drugs will potentiate each other when taken together.  This causes an intensification of effects that can overstimulate the GABA receptors.

To put it simply -- what started out as a fun night at the bar, could turn into a horrible experience if too much phenibut is involved.​  Do yourself a favor and never mix phenibut with other substances.

Other Common Phenibut Side Effects

  • Low Blood Pressure

Some users have reported low blood pressure symptoms such as blurry vision. This is understandable since phenibut is a CNS depressant whose main action is releasing potassium ions through the GABA receptors. However, this a rare symptom that occurs in some users who usually have predisposing conditions to low blood pressure.

  • Vivid Dreams

Another unique and interesting effect that some users have reported are unusual dream patterns. This is most likely due to an increase in the REM sleep cycle which allows users to vividly remember their dreams. This isn’t necessarily a negative effect until some users started experiencing disturbing nightmares when using high doses of phenibut. Within the recommended dosage, however, the majority of users report experiencing deep sleep and waking up much more refreshed.

  • Tolerance

This is one of the most well known side effects of phenibut. A tolerance to the drug can build extremely fast in some people, requiring them to dose more of the product to get the same effect.  As we discussed earlier in the article, cycling is really the only way to combat this. Increasing the dose is only going to lead to more problems later down the road.

experiencing side effects of phenibut

Tolerance → Dependence → Withdrawal

  • Withdrawal Symptoms

Phenibut withdrawal symptoms are unfortunate side effects reserved for those that do not heed dosing and cycling advice.  The intensity and length of their effects are dependent on how much phenibut the user was taking and for how long.  This experience will usually consist of anxiety, depression, loss of appetite and insomnia. Unfortunately, this can range from a few days to a few months depending on the individual situation.  To understand more about how phenibut withdrawal works, please read this article.

Final Thoughts

Phenibut is known to relieve feelings of anxiety, stress, and depression during challenging and difficult times but rumors of the horrible side effects may keep some people away.  A common concern are the issues of tolerance and the resulting effects of withdrawal.  It is important to keep in mind that most cases of negative effects exhibit deliberate abuse of the compound through taking exorbitantly high doses and/or not cycling the drug properly.

While it is true that side effects are possible, this is true of almost anything in the world when it is abused.  We believe that the benefits outweigh the phenibut side effects when used responsibly, so don't let the horror stories scare you away from enjoying the positive benefits that phenibut can offer. When used responsibly, phenibut can be an effective nootropic for many people.

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Nicole Sanders

Hi, I'm Nicole, chief editor at Nootropics Revealed. Learn more about me and my mission here.