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Peptide (research chemical) High risk

GB-115

Ranquilon; N-(6-phenylhexanoyl)glycyl-L-tryptophan amide · Evidence-based safety and harm-reduction overview.

Not medical advice. GB-115 is discussed here for informational and harm-reduction purposes only. We do not endorse use, and any dosing context is informational, not a protocol.
Also known asRanquilon; N-(6-phenylhexanoyl)glycyl-L-tryptophan amide
CategoryPeptide (research chemical)
Chemical nameN-(6-phenylhexanoyl)glycyl-L-tryptophan amide
Drug classSynthetic dipeptide; CCK-1 receptor antagonist; anxiolytic
Development originRussia; Phase 3 completed for neurasthenia and adjustment disorders
Highest human evidence levelPhase 3 trial data (Russian registry); 25-patient GAD pilot published in PMC
Regulatory statusNot FDA- or EMA-approved; investigational only; not a scheduled controlled substance in the US
Proposed differentiator from benzodiazepinesNon-GABA mechanism (CCK-1 antagonism); no sedation, dependency, or withdrawal in available data
US legal statusNot FDA-approved and not marketed in the United States. GB-115 is an investigational pharmaceutical compound that has completed Phase 3 trials in Russia but holds no approved marketing authorization from the FDA, EMA, or equivalent major regulatory bodies. It is not listed as a scheduled controlled substance in the US, but it is not legal for human use outside of authorized clinical research protocols. Its status is that of an unapproved investigational drug.
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What is GB-115?

GB-115 (also called Ranquilon) is a synthetic dipeptide developed in Russia, chemically identified as N-(6-phenylhexanoyl)glycyl-L-tryptophan amide. It is classified as a retro-analogue of cholecystokinin-4 (CCK-4) and functions as a selective antagonist of cholecystokinin-1 (CCK-1) receptors in the central nervous system. It was developed as an anxiolytic agent with a proposed mechanism of action fundamentally distinct from benzodiazepines, operating on the CCK signaling system rather than GABA transmission. It has been studied for generalized anxiety disorder, neurasthenia, and adjustment disorders, primarily within Russian and Eastern European clinical research settings.

How it works

GB-115 selectively antagonizes cholecystokinin-1 (CCK-1) receptors in the CNS. Cholecystokinin peptides, particularly CCK-4, are implicated in the mediation of anxiety and panic; by blocking CCK-1 receptor signaling, GB-115 is thought to attenuate anxiogenic signaling cascades without engaging GABA-A receptors. This mechanistic profile is proposed to underlie the absence of sedation, dependency, and disinhibition observed in preclinical and early clinical studies. The compound also reportedly exhibits mild psychostimulant properties alongside its anxiolytic effects, which may relate to the CCK system's role in dopaminergic modulation, though this aspect is not yet well-characterized in humans.

Background & history

GB-115 was developed in Russia as part of research into peptide-based CNS agents that could offer anxiolytic efficacy without the dependency and sedation liabilities of benzodiazepines. As a retro-analogue of CCK-4, it emerged from investigation into the cholecystokinin system's role in anxiety. The compound progressed through Phase 3 clinical trials in Russia for neurasthenia and adjustment disorders, with pilot human data also generated in generalized anxiety disorder. It has not achieved approved drug status in any major Western regulatory jurisdiction and remains largely confined to investigational use. The precise developer or patent holder is not clearly identified in publicly available literature.

What the research says

The evidence base for GB-115 is real but limited in scope and geographic reach, concentrated in Russian and Eastern European literature. Preclinical data in rodents and non-human primates demonstrates anxiolytic activity at oral doses of 0.1-5.0 mg/kg in mice, with rhesus monkey isolation-stress models showing effects described as comparable to phenazepam but without sedation or dependency signals. Human data consists of a pilot study in 25 patients with generalized anxiety disorder receiving 6 mg/day for 21 days, reporting substantial reductions on the Hamilton Anxiety Rating Scale (HARS median from 22 to 5, p less than 0.001) and the Multidimensional Fatigue Inventory (MFI-20 from 70 to 28, p less than 0.001), with no stimulation-related adverse events. Phase 3 trial data supports efficacy in neurasthenia and adjustment disorders. The human sample sizes are small, and independent replication in larger or Western-registered trials is absent. ClinicalTrials.gov lists completed and recruiting Phase 3 and Phase 4 records under "GB-115" and "Ranquilon." This compound has a plausible, well-theorized mechanism and peer-reviewed support, but the totality of human evidence remains preliminary by the standards applied to approved drugs.

Reported effects

Dosing & administration (informational)

Published literature describes a dose of 6 mg/day (administered as 2 mg tablets three times daily) in the pilot GAD study, and this same regimen is referenced in Phase 3 data for neurasthenia and adjustment disorders. Preclinical oral doses ranged from 0.1 to 5.0 mg/kg in mice. These figures are provided for informational reference to the published literature only and do not constitute a dosing recommendation or protocol. Anyone considering this compound for therapeutic use should consult a qualified clinician and access it only through a sanctioned clinical research context.

This is general research/context information, not medical advice or a recommended protocol.

Safety & side effects

Drug & supplement interactions

Who should avoid it

How it is commonly combined

No stacking data exists in published literature. GB-115 has not been studied in combination with other anxiolytics, antidepressants, or peptide compounds. Combination use is entirely uncharacterized in humans and cannot be commented on from the available evidence base.

Quality & harm reduction

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Frequently asked questions

Is GB-115 approved for medical use?

No. GB-115 has completed Phase 3 trials in Russia but holds no approved marketing authorization from the FDA, EMA, or equivalent major regulatory agencies. It is not legally available as a prescription or over-the-counter medication outside authorized clinical research.

How does GB-115 differ from benzodiazepines mechanistically?

Benzodiazepines act as positive allosteric modulators at GABA-A receptors, enhancing inhibitory neurotransmission broadly. GB-115 instead selectively antagonizes CCK-1 receptors in the CNS, targeting a completely different signaling pathway. This is proposed to explain the absence of sedation, dependency, and disinhibition effects seen in available data, though the human evidence base is small.

What does the human trial data actually show?

A pilot study in 25 patients with generalized anxiety disorder treated with 6 mg/day for 21 days reported statistically significant reductions in Hamilton Anxiety Rating Scale scores (median 22 to 5, p less than 0.001) and fatigue inventory scores. Phase 3 data also supports efficacy in neurasthenia and adjustment disorders. These results are preliminary; sample sizes are small and independent replication in larger Western trials is absent.

What is the recommended dose?

This is not something that can be appropriately answered here. Published literature describes 6 mg/day (2 mg three times daily) in the clinical pilot, but providing a protocol recommendation falls outside the scope of this reference. Anyone with a clinical interest should discuss this with a qualified clinician who has access to the full trial record.

Is GB-115 a controlled substance in the United States?

As of the available evidence base, GB-115 is not listed on the DEA schedules and is not a controlled substance in the United States. However, it is an unapproved investigational drug and is not legal for human use outside of authorized clinical research protocols. Regulatory status can change; verify current status through official channels before drawing conclusions.

Where is GB-115 in clinical development?

It has completed Phase 3 trials in Russia for neurasthenia and adjustment disorders, with Phase 4 records also appearing on ClinicalTrials.gov under the terms GB-115 and Ranquilon. It has not entered regulatory review in the US or EU and there is no indication of an active IND or IMPD filing in public records.

References & further reading

  1. PubMed PMID 24130989 - Anxiolytic Activity of Dipeptide GB-115 after Oral Administration, Bulletin of Experimental Biology and Medicine
  2. PubMed PMID 25322652 - Pharmacokinetics of three peroral dosage forms of new dipeptide anxiolytic drug GB-115
  3. PMC PMC9564032 - Clinical effects of central antagonist of cholecystokinin-1 receptors GB-115 in patients with Generalized Anxiety Disorder
  4. PubMed search: Role of Cholecystokinin System Anxiolytic Activity Dipeptide GB-115 (Springer DOI 10.1007/s10517-012-1842-1)
  5. ClinicalTrials.gov search terms: GB-115 OR Ranquilon (Phase 3 and Phase 4 records, completed and recruiting)

Medical & legal disclaimer. This site is for informational and harm-reduction purposes only. It is not medical advice and is not a substitute for a licensed healthcare professional. The compounds discussed are largely not approved by the FDA for human use and many are sold strictly as research chemicals 'not for human consumption.' Nothing here is an endorsement to purchase, possess, or use any substance. Laws vary by jurisdiction. Always consult a qualified physician and follow the law where you live.

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