Selank and Phenibut: Poorly Studied GABAergic Peptide Drugs Sold as Supplements in the US

Selank and phenibut are Russian-developed GABAergic compounds sold as unregulated dietary supplements in the US despite limited safety data, with phenibut poison control calls rising substantially over 5 years.

Doyno, Cassandra R et al.·Journal of clinical pharmacology·2021·n/a (review)Review
RPEP-05353Reviewn/a (review)2021RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Review
Evidence
n/a (review)
Sample
N=N/A
Participants
Review of pharmacology and abuse data for flunitrazepam, GHB, phenibut, and selank

What This Study Found

Selank and phenibut are poorly studied GABAergic drugs sold as US dietary supplements. Phenibut poison control calls have increased substantially, and both carry risks of dependence, withdrawal, and serious adverse effects when misused.

Key Numbers

Phenibut poison control calls rising over 5 years; high-dose GABA drugs cause respiratory depression, coma, death; chronic use causes dependence and withdrawal

How They Did This

Narrative review of pharmacology, clinical effects, abuse potential, and safety profiles of selected GABAergic agents including flunitrazepam, GHB, phenibut, and selank.

Why This Research Matters

People are buying selank and phenibut without prescriptions, often unaware of their risks. This review highlights the regulatory gap that allows poorly studied GABAergic peptides and drugs to be sold as supplements.

The Bigger Picture

The sale of unregulated GABAergic compounds as supplements raises serious safety concerns. As peptide-based supplements gain popularity, this review underscores the need for proper pharmacological evaluation before public access — particularly for substances with sedative and addictive potential.

What This Study Doesn't Tell Us

Narrative review, not systematic. Very limited clinical data on selank specifically — most information comes from Russian literature that may not meet international standards. The review groups selank with much more dangerous substances, which may overstate its individual risk profile.

Questions This Raises

  • ?Should selank be regulated differently from phenibut given that it is a peptide with a different safety profile?
  • ?What would rigorous clinical trials reveal about selank's actual efficacy and safety for anxiety?
  • ?Could selank offer benefits over benzodiazepines if properly studied, or does its GABAergic activity carry similar risks?

Trust & Context

Key Stat:
Rising poison control calls Phenibut-related calls to US poison control centers have increased substantially over 5 years, highlighting risks of unregulated GABAergic supplement sales
Evidence Grade:
Not applicable (narrative review). Highlights the lack of rigorous clinical evidence for selank and phenibut safety and efficacy.
Study Age:
Published in 2021. Regulatory attention to GABAergic supplements has continued to increase since publication.
Original Title:
Sedative-Hypnotic Agents That Impact Gamma-Aminobutyric Acid Receptors: Focus on Flunitrazepam, Gamma-Hydroxybutyric Acid, Phenibut, and Selank.
Published In:
Journal of clinical pharmacology, 61 Suppl 2, S114-S128 (2021)
Database ID:
RPEP-05353

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / ObservationalSnapshot without intervening
This study
Case Report / Animal Study

Summarizes existing research on a topic.

What do these levels mean? →

Frequently Asked Questions

Is selank safe to take as a supplement?

There is insufficient clinical evidence to confirm selank's safety. It is a synthetic peptide with GABAergic activity sold as a supplement in the US, but it has not undergone the rigorous testing required for FDA-approved medications. Caution is warranted.

What is the difference between selank and phenibut?

Selank is a synthetic peptide derived from the immune protein tuftsin with anxiolytic properties. Phenibut is a modified GABA molecule with stronger sedative effects. Both affect GABA receptors, but phenibut has a more established pattern of abuse, dependence, and withdrawal.

Read More on RethinkPeptides

Cite This Study

RPEP-05353·https://rethinkpeptides.com/research/RPEP-05353

APA

Doyno, Cassandra R; White, C Michael. (2021). Sedative-Hypnotic Agents That Impact Gamma-Aminobutyric Acid Receptors: Focus on Flunitrazepam, Gamma-Hydroxybutyric Acid, Phenibut, and Selank.. Journal of clinical pharmacology, 61 Suppl 2, S114-S128. https://doi.org/10.1002/jcph.1922

MLA

Doyno, Cassandra R, et al. "Sedative-Hypnotic Agents That Impact Gamma-Aminobutyric Acid Receptors: Focus on Flunitrazepam, Gamma-Hydroxybutyric Acid, Phenibut, and Selank.." Journal of clinical pharmacology, 2021. https://doi.org/10.1002/jcph.1922

RethinkPeptides

RethinkPeptides Research Database. "Sedative-Hypnotic Agents That Impact Gamma-Aminobutyric Acid..." RPEP-05353. Retrieved from https://rethinkpeptides.com/research/doyno-2021-sedativehypnotic-agents-that-impact

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.