Links & Sources:

http://www.ncbi.nlm.nih.gov/pubmed/11830761

http://www.ncbi.nlm.nih.gov/pubmed/?term=phenibut

http://en.wikipedia.org/wiki/Phenibut

http://www.webmd.com/vitamins-supplements/ingredientreview-1184-PHENIBUT.aspx?drugid=1184&drugname=PHENIBUT&pageIndex=1&sortby=3&conditionFilter=-500

First let me say this right off the bat, because there seems to be a lot of confusion around this: PHENIBUT. This drug is pronounced Fen-ih-byoot. The name phenibut comes directly from the chemical name for the compound, β-phenyl-γ-aminobutyric acid. And is pronounced: “FEN-ih-BYOOT” as in PHENyl-BUTyric Acid
*What is it?
Phenibut is sold legally in most counties as a dietary supplement. Many use Phenibut as a “performance enhancer,”. Let me state this CLEARLY, I am not a doctor nor medical practitioner of any kind, this review is based on personal experience and should NOT be construed as medical advice. Also, in the United States Phenibut is it not regulated by the FDA to treat any condition.
Because Phenibut is sold as a dietary supplement it can be purchased on the Internet and at many health food stores with other dietary supplements.
In Russia, Phenibut IS a considered a legal drug and was actually developed there by the Russians to combat anxiety in cosmonauts without causing cognitive impairment. It’s prescribed by doctors under the brand name Noofen to treat a wide range of ailments such as, anxiety, insomnia, depression, & in some cases PTSD.
*How it works
Phenibut (beta-phenyl-gamma-aminobutyric acid) is a derivative of GABA (gamma-aminobutyric acid). Unlike GABA, however, Phenibut can easily pass through the blood-brain barrier and bind to the GABA receptors in the brain. Compounds that bind to GABA receptors such as alcohol, can significantly reduce anxiety, produce moderate levels of euphoria and induce sleep in high doses.