← Back to Drugs A–Z

Phenibut

Group: Depressants
Nicknames: Anvifen, Fenibut, Bifren, Noofen, Phenigamma, Phenigama, Fenigam, F-but
Last reviewed: October 2026

Description

Phenibut is a depressant drug with anti-anxiety effects, with similarities to pregabalin and baclofen. Phenibut is used for the treatment of anxiety and insomnia in Russia, Ukraine, Belarus and Latvia. It is not approved for medical use in the UK, but is sold online as an unlicensed nootropic supplement.

Desirable Effects

  • Anti-anxiety
  • Euphoria
  • Increased sociability

Undesirable Effects

  • Headaches/dizziness
  • Feeling/being sick
  • Respiratory depression in combination with other depressants

What does it look like?

Tablets: Prescription tablets come in 250 mg or 500 mg doses. Tablets/capsules from nootropics or supplement vendors can have inconsistent doses between 0 and 1100 mg.

Liquid solution: 10 mg/mL for infusion

Power: Nootropics vendors typically sell phenibut in power form as either free amino acid (FAA) or salt (HCl)

Method of Use

Orally: swallowed as a tablet/capsule, powder dissolved and drunk as a liquid solution

Snorted: rarely snorted as a powder, avoided due to pain and swelling of the nostrils

Keep This Information Independent

Release is a registered charity. We rely on your support to provide expert, non-judgmental legal and harm reduction guidance to thousands of people every year.

Donate to Release