Phenibut is a GABA analog, which has anxiolytic effects.
Introduction to Phenibutβ-Phenyl-γ-aminobutyric acid (phenylGABA) one of the minor tranquilizers is a drug used for the treatment of anxiety and its related psychological and physical symptoms. Anecdotal evidence suggests Phenibut to be a nootropic displaying improve neurological functions.
Phenibut is derived from gamma-Aminobutyric acid. GABA is a primary mammalian central nervous system inhibitory neurotransmitter.
Using PhenibutPhenibut is a GABA derivative that was developed in the Soviet Union. It has a wide array of uses. Some of these uses include anxiolytic, nootropic, sleep-inducing, mood-enhancing, recreational, and growth-hormone manipulating effects. It is usually taken orally at doses ranging from 500 mg to 10 grams and above. Like all drugs, it can be extremely beneficial or extremely dangerous depending on the dosage, frequency of usage, and purity of the product. Its beneficial effects can range from neuroprotective, cardioprotective, antidepressant, and nootropic effects; and its negative effects can range from minor drowsiness to full blown addiction and seizures when usage is abruptly discontinued. It does have minor recreational potential and can be considered a drug of abuse.
Ways of Administration
Swallowing PhenibutPhenibut is usually administered orally from doses ranging from as low 500mg to as high 10grams - sometimes even more in chronic users. Phenibut HCl is slightly acidic so capsules may be preferred for some to avoid the taste. Insufflation would not be recommended as the dose would need to be very high and the acidity would cause nasal pain.
Snorting PhenibutSnorting Phenibut is not advised since it burns mucus membranes, and it would take too much powder to be effective.
Injecting PhenibutInjecting Phenibut HCl is definitely not recommended at all because its acidity can cause severe vascular damage and pain. If still insisted, one should obtain the free amino acid form (less common and usually sold as "phenibut FAA"), which has a more neutral pH, and make sure to read up on all the warnings and possible interactions on injecting Phenibut. Here's a good thread/warning for someone who tried to IM Phenibut.
Plugging PhenibutPlugging Phenibut HCl is definitely not recommended because its acidity can cause severe tissue damage and pain. If still insisted, one should obtain the free amino acid form (Phenibut FAA), which has a more neutral pH, and make sure to read up on all the warnings and possible interactions on plugging Phenibut.
Effects of PhenibutReputed Positive Effects:
- Improved Cognitive Functioning
- Improved Mood and Increase in Energy
- Muscle Relaxation
- Confusion and Dizziness
- Rapid Development of Tolerance
Negative Effects and Withdrawal Symptoms:
Like most GABAergic drugs, tolerance develops quickly and there can be withdrawal symptoms after cessation of consistent usage for extended periods of time. Some of these symptoms can be:
- Rebound Anxiety
- Panic Attacks
- Tremors or Shaking Hands
- Muscle Spasms
- Restlessness and inability to feel comfortable
- Cognitive deficits
- Irritability and Rage
- Paradoxical effects
Combinations with Phenibut
Different Uses for Phenibut- Phenibut is commonly used as a sleep-aid for those with insomnia or trying to induce a state of relaxation and calmness to allow for an easier transition into sleep.
- Phenibut has a reputation for being a nootropic. It is reported to enhance cognition, focus and concentration, motivation to work, and minor dis-inhibition to allow for unrestrained creativity. Its anxiolytic properties also allow for cognitively demanding tasks to be undertaken with reduced stress.
- It has often been used as an anxiolytic. It has been used by people generalized-anxiety disorders, panic-disorders, and other anxiety provoking situations.
- In the bodybuilding community Phenibut is widely used as it is suggested to increase human-Growth-Hormone (hGH) production. However its efficacy in this area is under dispute.
- It is used in the treatment of alcoholism
- In the treatment of PAWS (Post Acute Withdrawal Syndrome)
- Used for the treatment of a irregular heartbeat
- Used to treat depression
- Improving memory and cognitive performance
Pharmacology of PhenibutPhenibut is known to act primarily as a non-selective agonist at the GABAb metabotropic receptor in the central nervous system. It also acts to a lesser extent at the GABAa ionotropic receptor site. Phenibut is also a dopamine receptor agonist (although it is unclear exactly how phenibut's mechanism works on the DA system and what specific areas of the dopaminergic system is acts upon) and an antagonist of the neuromodulator and anxiogenic beta-phenethylamine in the central nervous system.
GABA itself is bio-synthesized in vivo in the mammalian brain from glutamate acid undergoing decarboxylation. Exogenous GABA however cannot pass through the blood-brain-barrier very well due to high hydrophilicity. With Phenibut, the additional phenyl-ring allows greater blood-brain-barrier permeability and attaching to the designated site (the GABA receptor complex).
LD50 (mg/kg) (as the hydrochloride) :
Mice : 900 intraperitoneally
Rat : 700 intraperitoneally
Chemistry of Phenibut
Column 1 Column 2 Systematic (IUPAC) name: (RS)-4-amino-3-phenylbutanoic acid Synonyms: β-(aminomethyl)benzenepropanoic acid, β-(aminomethyl)hydrocinnamic acid, 4-amino-3-phenylbutyric acid, β-Phenyl-γ-aminobutyric acid, fenibut, phenibut, phenigamma, phenygam, PhGABA Molecular Formula: C10H13NO2 Molar mass: 179.22 g/mol, 260.13 g/mol (hydrobromide), 215.68 g/mol (hydrochloride) CAS Registry Number: 1078-21-3, 103095-38-1 (hydrobromide), 3060-41-1 (hydrochloride) Melting Point: 250-253°C (with decomposition), 114°C (hydrobromide) Boiling Point: no data Flash Point: no data Solubility: no data Additionnal data: none Notes: Hydrobromide aspect : irregular patelets; crystallized from benzene
Structure - Phenibut structurally related to the amino-acid and inhibitory neurotransmitter GABA (γ-Aminobutyric acid). It only differs from GABA structurally by having a phenyl group attached to the third carbon of butyric acid.
The Dangers of PhenibutLong-term phenibut use can lead to dependence. Abruptly discontinuing a phenibut habit can cause highly unpleasant withdrawal symtoms, similar to benzodiazapine drugs, so it is recommended to taper off.
In addition, phenibut dehydrates you, so it's recommended to drink plenty of water. Those who use phenibut to help with sleep often put water by their bedside.
Forms of PhenibutPhenibut is sold in two forms currently, the HCl and Free Amino Acid. It is also sold in raw powder or dispensed in capsules for easier dosing.
Legal Status of Phenibut
USAPhenibut is legal and uncontrolled in the U.S.. 
EUPhenibut is uncontrolled in the United Kingdom. 
Other CountriesCurrently (7/30/13) Phenibut is unscheduled in Canada and is available without a prescriptions. There are no legislative parameters placed on Phenibut.
History of Phenibut
More Phenibut Sections
 Merck Index, fifteenth edition (2013)