Drug Interactions, Kratom Guides

Phenibut & Kratom: How to Stay Safe

Phenibut has faced a lot of regulatory trouble in various countries, but that does not mean it holds no value as a medication.

If you’re in a country that allows phenibut and you also happen to enjoy kratom, you should check out this handy guide. It will fill you in on everything you need to know in order to stay safe while using these compounds.

Last updated 4 months ago by Dr. Devin Carlson

Phenibut & Kratom: How to Stay Safe

Does Kratom Interact With Phenibut?

Kratom and phenibut can interact in a few ways.

Phenibut acts on the central nervous system (CNS) as a depressant. Kratom’s interaction with the CNS is slightly more complicated, as it has both stimulant and depressant qualities. However, kratom also interacts with opioid receptors like other opioids do, which are also depressants.

This means that kratom and phenibut likely have an agonistic interaction in terms of their pharmacological effects. This interaction happens when two drugs work towards the same results and typically entails an increased risk of adverse effects.

However, kratom is also a stimulant, so these two can also have an antagonistic interaction, where two drugs have opposite effects and counteract each other.

In metabolic terms, it’s hard to determine their exact relationship since very little is known about the pharmacokinetics of phenibut.

However, the WHO Expert Committee on Drug Dependence released a paper saying phenibut shows minimal metabolization and is excreted in the urine largely unmetabolized. This suggests that kratom and phenibut aren’t metabolic competitors.

Is it Safe to Take Kratom With Phenibut?

Combining kratom and phenibut could be a high-risk interaction. Kratom is relatively safe, and while phenibut can cause fatalities, it does appear to be well-tolerated on average. However, this can easily change when compounds are mixed.

In general, mixing kratom with any CNS depressant is a bad idea as it can lead to respiratory depression — the leading cause of death in opioid-related drug use — and increase the incidence of other side effects.

In order to stay safe, we recommend that you avoid mixing kratom and phenibut, especially at higher doses. Talk to your doctor if you have questions.

What is Phenibut?

Phenibut — sold under the brand names Anvifen, Fenibut, and Noofen — is a CNS depressant. It is mainly used for its anxiolytic (anti-anxiety) effects. Phenibut may be ingested orally as a tablet or intravenously.

Phenibut is an analog of the GABA neurotransmitter — a key inhibitory neurotransmitter in the body. It has a similar profile to other GABA analogs such as baclofen.

The FDA has not approved Phenibut for use in the United States. In 2019, the FDA warned that certain dietary supplements companies were using phenibut in their products and reminded the public that this is a violation of the law. It is also banned in most of Europe. Phenibut is mainly used in Russia, where it is a prescription-only medication.

Drug NamePhenibut
Trade NameAnvifen, Fenibut, and Noofen
ClassificationGABA analog
CYP MetabolismNot CYP mediated
Interaction With KratomAgonistic and antagonistic interaction
Risk of InteractionMedium to high

What is Phenibut Used for?

Phenibut has anxiolytic, relaxant, and supposedly nootropic (cognition enhancing) properties [1].

It is prescribed in certain countries for the treatment of a wide array of ailments [1]:

  • Anxiety
  • Insomnia
  • Depression
  • Asthenia
  • Alcoholism
  • PTSD
  • Vestibular disorders
  • Ménière’s disease
  • Dizziness
  • Prevention of motion sickness

Phenibut can also be bought on the internet, where it is frequently marketed as a nootropic drug with potent cognitive enhancing benefits. However, there is scarce medical literature to substantiate these claims.

Related: Kratom vs. Phenibut

Generic & Brand Name Versions

Phenibut can be found under the following brand names:

  • Anvifen
  • Fenibut
  • Noofen

What’s the Dose of Phenibut?

The general recommended dose of phenibut is 0.25-2 g per day [2], although these numbers could vary depending on what is being treated.

However, it’s important to note that only people receiving a phenibut prescription get a qualified opinion. If this is not your case and you’re self-administering phenibut, you should consult your doctor and ask what legal alternatives are available.

What Are the Side Effects of Phenibut?

On average, phenibut is well-tolerated, but it does have side effects that you need to know about [1]:

  • Sedation
  • Somnolence
  • Nausea
  • Irritability
  • Agitation
  • Anxiety
  • Dizziness
  • Headache
  • Skin rashes
  • Motor incoordination
  • Loss of balance

Prolonged use of phenibut at high doses may result in the following:

  • Eosinophilia
  • Fatty liver disease

Aside from its adverse effects, phenibut is known to cause physical and mental dependency and there have been several cases of lethal overdose [3]. Also, suddenly stopping phenibut use may lead to withdrawal symptoms.

Contraindications to phenibut are:

  • Known sensitivity to the compound
  • Pregnancy and breastfeeding
  • Children under 2 years of agee
  • Renal impairment
  • Ulcerative lesions of the gastrointestinal tract

What is Kratom?

Kratom is an organic herbal compound made from the leaves of the Mitragyna speciosa, a tropical evergreen tree native to Southeast Asia. Kratom has been used for centuries by indigenous communities in Asia for its wide range of psychoactive benefits.

Kratom is filled with alkaloids, giving it special properties. The two most abundant are mitragynine and 7-hydroxymitragynine.

The alkaloids contained in kratom interact with the body similarly to opiates. They bind to opioid receptors in the body and create comparable effects. For this reason, kratom is an effective treatment for opioid withdrawal. However, it is crucial to note that kratom is addictive and causes more side effects in larger doses.

What is Kratom Used for?

The effects of kratom will vary depending on the dose.

In low doses, kratom can increase physical and mental energy, increase focus, enhance creativity, and give feelings of euphoria.

With medium to high doses, kratom is a potent analgesic and can also provide anxiolytic (anti-anxiety) benefits. Additionally, higher doses can also promote sedative-like effects.

And as if that weren’t enough, kratom has also been used successfully to treat the withdrawal symptoms stemming from opioids, benzodiazepines, and alcohol. Additionally, kratom has shown promise as a weight-loss supplement.

Only time will tell what other uses will be discovered.

What’s the Dose of Kratom?

As with most other drugs, dosage recommendations vary according to several factors, such as the method of consumption and treatment goals.

In general, it’s never a good idea to take a formulaic approach to kratom dosage recommendations.

However, you can probably follow these dosage guidelines to start with. Just remember to start with a low dose:

  • Low dose (1-5 g)
  • Medium dose (5-10 g)
  • High dose (10-12 g)

First-timers should never exceed 5 grams of kratom.

What Are the Side Effects of Kratom?

Kratom has its fair share of side effects; the most common are nausea, headaches, dizziness, and fatigue. Most of these effects can be avoided by going low and slow with the dose. These side effects are much more common with larger amounts.

The side effects of kratom may include:

  • Dizziness
  • Insomnia
  • Itchiness
  • Loss of muscle coordination
  • Low blood pressure
  • Low libido
  • Poor appetite
  • Seizures
  • Tremors or muscle contractions

Additionally, kratom consumption can cause an addiction. Thankfully, its overdose potential is relatively low. Overall, kratom is safe and helpful for most people.

What Are the Different Types of Kratom?

Good news for all who like to tweak their consumption to find the perfect experience: kratom is available in various strains, and they offer unique effects.

These strains contain the same basic properties, but they each emphasize certain effects to differing extents.

Make sure to try out different strains to find the one that works best for you. Remember that even though they are all named after a particular color, they’ll look the same once processed.

A) White Vein Kratom

White vein kratom offers mind-based, nootropic benefits, such as increased attention span, creativity, a general improvement in mental energy, and euphoria.

B) Red Vein Kratom

Red vein kratom is an extremely popular strain for those dealing with chronic pain. It is the ideal strain for getting the most out of kratom’s analgesic and anxiolytic benefits.

These effects are triggered only through medium to high dosages, so the red-veined strains can be excellent for those who want these benefits but don’t want to consume a large amount of kratom.

C) Green Vein Kratom

Green vein kratom is best thought of as a mixture of red and white kratom. It has a great balance of benefits and can exemplify the whole breadth of the kratom spectrum.

D) Yellow Vein Kratom

Yellow vein kratom is quite similar to green-veined strains. Its main attribute is the fact that it’s milder than the other three strains.

Key Takeaways: Is it Safe to Mix Kratom & Phenibut?

It is not advisable to mix kratom with any sort of central nervous system depressant as this can potentiate adverse opioid-like side effects. Only your doctor can tell if a limited dosage won’t put you at imminent risk of severe adverse effects, but we still recommend you stay away from it.

Consult your doctor if you feel the need to engage in a combination such as this. Given phenibut’s many regulatory troubles in Europe and the United States, it’s likely that another medication could work better.


  1. Lapin, I. (2001). Phenibut (β‐phenyl‐GABA): A tranquilizer and nootropic drug. CNS drug reviews, 7(4), 471-481.
  2. Kupats, E., Vrublevska, J., Zvejniece, B., Vavers, E., Stelfa, G., Zvejniece, L., & Dambrova, M. (2020). Safety and tolerability of the anxiolytic and nootropic drug phenibut: a systematic review of clinical trials and case reports. Pharmacopsychiatry, 53(05), 201-208.
  3. Graves, J. M., Dilley, J., Kubsad, S., & Liebelt, E. (2020). Notes from the Field: Phenibut Exposures Reported to Poison Centers—United States, 2009–2019. Morbidity and Mortality Weekly Report, 69(35), 1227.

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