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Monograph
RESEARCH GREYN-001
Cognition

Phenibut

GABA-B receptor agonist with secondary calcium-channel modulation. Soviet-developed anxiolytic + sleep aid.

EmergingCognition
Typical dose250-500 mg
Frequencyoccasional only — never daily; max 2× per week to avoid tolerance + withdrawal
Half-life5h
Citations indexed17
DeliveryOral
Half-life~5h
EvidenceEmerging
Citations17
Similar compounds
Synergy checkCompare
Research grey

This compound sits in research-grey territory. The caveats below carry more weight than for FDA-approved entries — read them.

Mechanism

β-phenyl-γ-aminobutyric acid. Crosses the blood-brain barrier where GABA itself cannot. Acts primarily on GABA-B receptors (Baclofen-class binding); at higher doses also on GABA-A. Russian-published clinical use since 1975 for anxiety, sleep onset, and ethanol withdrawal — sparse Western trial data. Tolerance develops fast (within 5-7 days of consecutive dosing) and withdrawal at therapeutic-range doses can be severe and prolonged. Not classified as a controlled substance federally in the US, but banned in Australia and several US states.

Specifics
AnxietySleep quality / depth
Field reports

Distilled themes from named communities — Reddit threads, forums, creator commentary. Not direct quotes; not clinical evidence. Useful for calibrating expectations against what real self-experimenters report.

r/Nootropics weekly experience threads

Self-reports converge on phenibut working too well and withdrawal hitting too hard. Cohort consensus: weekend-only, never stack consecutive days, never combine with alcohol.

Caveats

TOLERANCE + WITHDRAWAL ARE THE PRIMARY RISK. Consecutive-day dosing builds tolerance within a week; abrupt cessation can produce severe anxiety, insomnia, dysphoria, and seizures lasting weeks. Treat phenibut like alcohol: weekend-only at most, never as a daily nootropic. Never combine with alcohol, benzodiazepines, opioids, or barbiturates — all act on GABA pathways and respiratory depression risk multiplies. Banned in Australia, Hungary, Italy, Lithuania, Russia (Rx-only), and several US states.

Evidence levelEmerging
Regulatory statusNot FDA-approved. Not a controlled substance federally. State-level bans: see /can-i-get-it.
DNA / pharmacogenomicsMostly marketing — No documented pharmacogenomic literature. CYP-mediated metabolism is incompletely characterized.
References

External links to PubMed searches, ClinicalTrials.gov, and FDA materials. We do not host papers — we point at canonical sources.

  • PubMedEN
    REVIEWFunding undisclosedVerified 3d ago
    PubMed — Phenibut clinical literature
  • PubMedEN
    REVIEWAcademic-fundedVerified 3d ago
    Lapin IP — Phenibut: discovery, characterization, pharmacology (CNS Drug Reviews 2001)
  • RegulatoryEN
    REGULATORYNIH-fundedVerified 3d ago
    FDA Warning — Phenibut as unapproved new drug + dietary-ingredient violation
RESEARCH GREYN-001

Not FDA-approved. Not a controlled substance federally. State-level bans: see /can-i-get-it.

Phenibut250-500 mg · occasional only — never daily; max 2× per week to avoid tolerance + withdrawal
Discussion guide, not prescription

stack is an exploration engine. Output is a discussion guide for a conversation with a licensed provider — never a prescription, dose recommendation, or sourcing instruction. Peptides discussed include compounds with limited human evidence and varying legal status by jurisdiction. Verify everything with a qualified clinician before any decision.

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