F-Phenibut

F-Phenibut (also known as fluorophenibut, fluorobut, or fphenibut) is a central nervous system depressant and close analogue of its popular predecessor phenibut. F-Phenibut possesses an effect profile nearly identical to phenibut but with a several-fold increased potency in its active dose. This also includes a significantly quicker onset as well as a shorter total duration. Very little is known about this substance, particularly its potential toxicity and addiction potential, but it has recently become available through online research chemical vendors.

F-Phenibut
Chemical Nomenclature
Common names	F-Phenibut, Fluorophenibut, Fluorobut
Substitutive name	β-(4-flourophenyl)-GABA
Systematic name	5-amino-4-(4-fluorophenyl)-1-hydroxypentan-2-one
Class Membership
Psychoactive class	Depressant
Chemical class	Gabapentinoid
Routes of Administration
WARNING: Always start with lower doses due to differences between individual body weight, tolerance, metabolism, and personal sensitivity. See responsible use section. ⇣ Oral Dosage Threshold 50 mg Light 100 - 150 mg Common 150 - 400 mg Strong 400 - 600 mg Heavy 600 mg + Duration Total 6 - 8 hours Onset 20 - 60 minutes DISCLAIMER: PW's dosage information is gathered from users and resources for educational purposes only. It is not a recommendation and should be verified with other sources for accuracy.
Interactions
Stimulants
Depressants
Dissociatives

Summary sheet: F-Phenibut

In terms of its pharmacology, this compound can be classified as a gabapentinoid, a class which contains other drugs such as baclofen, pregabalin, gabapentin, and GABOB. Fluorophenibut, like its parent compound, is a derivative of the naturally occurring inhibitory neurotransmitter γ-aminobutyric acid (GABA), but with an addition of a phenyl ring that allows it to cross the blood–brain barrier.

Chemistry

F-phenibut is a derivative of GABA with a fluorine-substituted phenyl group in the β-position. It is a chiral molecule and thus has two potential configurations as (R)- and (S)-enantiomers. It has an almost identical chemical structure to baclofen (only replacing a chlorine with a fluorine atom in the para-position of the phenyl group). Additionally, the widely prescribed gabapentinoid pregabalin also possesses a similar structure as phenibut, except that the phenyl group is instead replaced with an isobutyl group.

Pharmacology

Due to the lack of research regarding the substance, all discussion regarding the pharmacology of it is purely speculation based upon its structural and subjective effect similarities to other depressants or gabapentinoid such as phenibut, gabapentin, and pregabalin.

Among other things, it is likely that this compound exerts its effects by binding to the α2δ-1 site of voltage-gated calcium channels in a manner which is similar to that of other gabapentinoids. By binding to this site, F-Phenibut may reduce the release of several excitatory neurotransmitters, including glutamate, substance P, acetylcholine, and norepinephrine. This, in turn, increases GABAergic activity. As the GABA system is the most prevalent inhibitory receptor set within the brain, its modulation may be responsible for the relaxing, sedating, and calming effects of F-Phenibut on the central nervous system.

Subjective effects

Disclaimer: The effects listed below cite the Subjective Effect Index (SEI), an open research literature based on anecdotal user reports and the personal analyses of PsychonautWiki contributors. As a result, they should be viewed with a healthy degree of skepticism.

It is also worth noting that these effects will not necessarily occur in a predictable or reliable manner, although higher doses are more liable to induce the full spectrum of effects. Likewise, adverse effects become increasingly likely with higher doses and may include addiction, severe injury, or death ☠.

In comparison to regular phenibut, this compound has a significantly faster onset, a shorter duration, and slightly less stimulation. Early reports suggest that in comparison to other commonly used GABAgenic depressants such as alcohol or benzodiazepines, this compound produces less inebriation and more euphoria, giving it more recreational potential as well as a correspondingly higher risk of abuse.

Physical effects

• Stimulation and Sedation - At lower doses, F-Phenibut has a mild physical and mental stimulation effect, encouraging movement, wakefulness, productivity and socialization. At higher doses, however, it becomes physically sedating, encouraging sleep and lethargy. Sleeping after dosing a small amount may result in a deep, restful sleep which can leave the user feeling refreshed and alert upon waking.
• Physical euphoria
• Respiratory depression
• Nausea - F-Phenibut can induce mild to extreme nausea depending greatly on dose and tolerance. It usually manifests roughly 5 hours after the initial dose and generally involves waves of nausea accompanied by excessive sweating and vomiting.
• Motor control loss
• Stomach cramps
• Dizziness
• Dehydration - Dehydration is typically reported to occur from regular multiday usage or excessive doses; however, it can also be present even in average doses of the substance (although perhaps to a lesser degree than phenibut).
• Headaches - Moderate to high doses have been reported to be a induce a mild to strong headache, typically many hours after dosing or during the comedown period.
• Muscle cramps - Muscle cramps and joint pain are sometimes accompanied at high doses.
• Frequent urination
• Appetite enhancement

Cognitive effects

• Empathy, love, and sociability enhancement - Unlike alcohol which merely increases sociability through disinhibition, F-Phenibut presents entactogenic effects which, although much weaker than that of traditional entactogens such as MDMA, are still prominent and well-defined even at moderate doses.
• Disinhibition
• Information processing suppression - High doses will usually induce a state of mild stupor and confusion.
• Thought deceleration
• Cognitive euphoria
• Motivation enhancement
• Anxiety suppression
• Depression - A low mood can be experienced as an after effect of high or frequent dosing.
• Amnesia - In comparison to many other GABAergics, this component is very weak except at very high doses
• Increased music appreciation

Experience reports

Anecdotal reports which describe the effects of this compound within our experience index include:

• Experience:400mg and 300mg of fluorophenibut
• Experience:F-Phenibut

Additional experience reports can be found here:

• Erowid Experience Vaults: Phenibut

Toxicity and harm potential

Main article: Research chemicals § Toxicity and harm potential

F-Phenibut likely has a low toxicity relative to dose. However, it is [[Toxicity::potentially lethal when mixed with depressants like alcohol, benzodiazepines or opioids]].

The toxicity and long-term health effects of recreational F-Phenibut use do not seem to have been studied in any scientific context and the exact toxic dosage is unknown. This is because F-Phenibut has very little history of human usage. Anecdotal evidence from people who have tried this substance within the community suggests that there do not seem to be any negative health effects attributed to simply trying this substance at low to moderate doses by itself and using it sparingly (but nothing can be completely guaranteed).

It is strongly recommended that one use harm reduction practices when using this substance.

Tolerance and addiction potential

F-Phenibut is moderately physically and psychologically addictive, although this usually only occurs with heavy abuse of the substance. This is likely even more so than its predecessor phenibut since its more rapid onset allows more convenient compulsive redosing.

Tolerance will develop to the sedative-hypnotic effects within a couple of days of continuous use. After cessation, the tolerance returns to baseline in 7 - 14 days. Withdrawal symptoms or rebound symptoms may occur after ceasing usage abruptly following a few weeks or longer of steady dosing and may necessitate a gradual dose reduction.

Withdrawal symptoms likely include severe anxiety, nervousness, hallucinations, tremors, agitation, dizziness, tension, irritation, rapid heartbeat, fatigue, loss of appetite, nausea, vomiting, psychosis, and insomnia in a similar manner to phenibut.

F-Phenibut presents cross-tolerance with [[Cross-tolerance::all GABAgenic depressants]], meaning that after its consumption most depressants will have a reduced effect.

Dangerous interactions

Although many substances are safe on their own, they can become dangerous and even life-threatening when combined with other substances. The list below contains some common potentially dangerous combinations, but may not include all of them. Certain combinations may be safe in low doses of each but still increase the potential risk of death. Independent research should always be done to ensure that a combination of two or more substances is safe before consumption.

• Depressants (1,4-Butanediol, 2-methyl-2-butanol, alcohol, barbiturates, GHB/GBL, methaqualone, opioids) - This combination can result in dangerous or even fatal levels of respiratory depression. These substances potentiate the muscle relaxation, sedation and amnesia caused by one another and can lead to unexpected loss of consciousness at high doses. There is also an increased risk of vomiting during unconsciousness and death from the resulting suffocation. If this occurs, users should attempt to fall asleep in the recovery position or have a friend move them into it.
• Dissociatives - This combination can result in an increased risk of vomiting during unconsciousness and death from the resulting suffocation. If this occurs, users should attempt to fall asleep in the recovery position or have a friend move them into it.
• Stimulants - It is dangerous to combine F-Phenibut with stimulants due to the risk of excessive intoxication. Stimulants decrease the sedative effect of F-Phenibut, which is the main factor most people consider when determining their level of intoxication. Once the stimulant wears off, the effects of F-Phenibut will be significantly increased, leading to intensified disinhibition as well as other effects. If combined, one should strictly limit themselves to only using a certain amount of F-Phenibut per hour. This combination can also potentially result in severe dehydration if hydration is not monitored.

Legal issues

This legality section is a stub. As such, it may contain incomplete or wrong information. You can help by expanding it.

• United Kingdom - It may be illegal to produce, supply, or import this substance under the Psychoactive Substance Act 2016, which blanketly applies the aforementioned restrictions on all "psychoactive substances" with exemptions for alcohol, nicotine and "medicinal products."

See also

• Responsible use
• Research chemical
• Depressants
• Nootropics
• Phenibut
• Gabapentin
• GHB

External links

• F-Phenibut (Erowid Experiences)