First you must understand what GHB (gamma-Hydroxybutyric acid) is..

GHB is the

"Gamma-hydroxybutyrate, or GHB, is an illegal drug that is sometimes used as a 'party drug' in the dance and club scene. It produces feelings of euphoria, relaxation and sociability, etc".

GHB is also used as a narcolepsy medication (Xyrem) which helps people with narcolepsy have a deeper sleep and become more rested in the morning so they don't have sleep attacks in the day. It works on GABA-B receptors.

Alcohol works as a GABA-A receptor positive allosteric modulator. Benzodiazepines work on GABA-A receptors and also as a GABA-A receptor positive allosteric modulator which is why they can be used to help people withdraw from alcohol.

When you take drugs that bind to GABA-A receptors, tolerance builds quickly and withdrawal is horrible and long lasting. When you take drugs that bind to GABA-B receptors, tolerance builds less quickly and the withdrawal is less horrible and not as long lasting.

Phenibut is beta-phenyl-GABA or Aminophenylbutyric acid. Baclofen is beta-chlorophenyl-GABA or beta-chlorophenylaminobutyric acid (Chlorinated phenibut). Baclofen is a prescription medication that is used - Like benzos, to help people withdraw from alcohol but can be used for phenibut withdrawal. Baclofen is also used as a muscle relaxant for treatment of muscle spasticity.

Phenibut is a prescription medication in Russia (Cosmonauts used it to help with anxiety in space) at 250mg-500mg 3x a day.

Many people often getting so addicted to phenibut that they take 10-15-20-25 or even 30 grams a day.