Rankings / Mood, Anxiety & Stress
Phenibut (β-phenyl-GABA)
Mood, Anxiety & Stress · GABA-B agonist (with weak GABA-A activity)
Tier D
High-risk evidence profile
Bottom line
Read Off Label grades Phenibut (β-phenyl-GABA) as D (2.9/10) based on weak evidence, moderate benefit magnitude, and a high-risk safety profile.
Its high-risk evidence profile reflects a Safety score of 2/10; reported benefits and harms can differ by indication, dose, route, duration, and population.
Popular among biohackers for social anxiety / public speaking / occasional use.
Studied, labeled, or reported-use context: 250-1000 mg PO in reported nonmedical protocols; dependence risk rises with repeated or frequent… — Russia (Rx — Anvifen, Noofen); not FDA-approved in US; not a lawful dietary supplement ingredient; sold as research chemical; UK/Australia controlled; not individualized guidance.
What the evidence says
Popular among biohackers for social anxiety / public speaking / occasional use. Tolerance to anxiolytic effect develops within days; rebound anxiety on cessation. Severe withdrawal protocol-dependent (taper with baclofen as cross-tolerant agent). Rapid tolerance, physical dependence, and severe withdrawal are documented; nootropic forums nevertheless commonly promote it. FDA April 2026 Addall alert found phenibut in a dietary supplement and reiterated addiction, withdrawal, loss of consciousness, and dangerous interaction risks. Consumer protocols sometimes limit exposure to 1-2 times weekly, but this has not been validated as a safe frequency and dependence can still occur.
Mechanism
Russian-developed (1960s) GABA analog with a phenyl ring that allows BBB penetration; full GABA-B receptor agonist (similar to baclofen) plus weak GABA-A modulation; anxiolytic, prosocial, mildly euphoric at higher doses
Studied, labeled, or reported dose & route
250-1000 mg PO in reported nonmedical protocols; dependence risk rises with repeated or frequent exposure
This records doses and routes described in studies, approved labeling, clinical practice, or documented use. It is not individualized guidance and does not establish safety; context changes with indication, formulation, health history, monitoring, and other medicines.
Citations
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Common questions
- What does the evidence show about Phenibut (β-phenyl-GABA)'s effects?
- Read Off Label rates the evidence for Phenibut (β-phenyl-GABA) as Weak and the benefit magnitude as moderate, producing an overall grade of D (2.9/10). Popular among biohackers for social anxiety / public speaking / occasional use.
- What safety findings are reported for Phenibut (β-phenyl-GABA)?
- Phenibut (β-phenyl-GABA) has a high risk profile in the database. High (rapid tolerance development; physical dependence; severe withdrawal — Pebis 2019 reviews 31 case reports of withdrawal syndrome including delirium, seizures, psychosis; typical 'biohacker mistake' is using daily and developing dependence in weeks) Legal status: Russia (Rx — Anvifen, Noofen); not FDA-approved in US; not a lawful dietary supplement ingredient; sold as research chemical; UK/Australia controlled.
- What does the low Safety score for Phenibut (β-phenyl-GABA) represent?
- The Safety score is 2/10. It records the substantial harms described for one or more use contexts; the Benefit score, indication, dose, route, duration, population, and legal status remain separate parts of the evidence profile.
- What doses or routes are reported for Phenibut (β-phenyl-GABA)?
- 250-1000 mg PO in reported nonmedical protocols; dependence risk rises with repeated or frequent exposure This is context from studies, approved labeling, clinical practice, or documented use; it is not individualized guidance and does not establish safety.
- How does Phenibut (β-phenyl-GABA) work?
- Russian-developed (1960s) GABA analog with a phenyl ring that allows BBB penetration; full GABA-B receptor agonist (similar to baclofen) plus weak GABA-A modulation; anxiolytic, prosocial, mildly euphoric at higher doses
This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.