GSB-106 — Safety, Research, Risks & Legal Status

Not medical advice. GSB-106 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 as	Bis-(N-monosuccinyl-L-seryl-L-methionine) hexamethylenediamide; BDNF loop-4 dipeptide mimetic
Category	Peptide (research chemical)
Drug class	Synthetic dimeric dipeptide; BDNF mimetic; TrkB receptor agonist
Developer	V.V. Zakusov Research Institute of Pharmacology, Moscow (T.A. Gudasheva, S.B. Seredenin)
Development stage	Preclinical only; no human trial registered or completed as of knowledge cutoff
Oral bioavailability (rabbit, tablet)	~161% relative to raw substance by HPLC-MS in one pharmacokinetic study
Target receptor	TrkB (NTRK2); downstream PI3K/Akt, MAPK/ERK, PLC-gamma
Independent replication	Minimal; substantially all published data originate from the originating Russian institute
US legal status	Not FDA-approved for any indication. No IND, Phase I, II, or III trial is listed on ClinicalTrials.gov. GSB-106 does not appear on any approved drug list (FDA, EMA, MHRA, Health Canada, TGA). It is an unapproved investigational compound not authorized for human use in the United States. No documented marketing authorization in Russia has been located in the public literature. Possession and use status varies by jurisdiction; it is not a scheduled substance under the US Controlled Substances Act as of the knowledge cutoff, but it is also not a lawful drug or dietary supplement under US law.

What is GSB-106?

GSB-106 is a synthetic dimeric dipeptide designed to mimic the fourth loop region of brain-derived neurotrophic factor (BDNF). It was engineered as a small-molecule TrkB receptor agonist intended to replicate BDNF's neurotrophin signaling in a format that is small enough to cross the blood-brain barrier and be orally bioavailable - properties that full-length BDNF protein lacks. All research to date is preclinical, originating from a single Russian pharmacology institute.

How it works

GSB-106 binds TrkB (NTRK2), the primary high-affinity receptor for BDNF, and activates three canonical downstream signaling cascades: PI3K/Akt (cell survival and anti-apoptotic signaling), MAPK/ERK (synaptic plasticity and neurite growth), and PLC-gamma (calcium-dependent signaling). This pattern is intended to reproduce the bioactive BDNF signal in rodent CNS tissue. Whether this mechanism translates to humans is entirely unknown.

Background & history

GSB-106 was developed at the V.V. Zakusov Research Institute of Pharmacology in Moscow (Russian Academy of Medical Sciences), principally by Tatiana A. Gudasheva and Sergey B. Seredenin. The compound emerged from a program to engineer low-molecular-weight peptidomimetics of neurotrophins, motivated by the long-standing clinical limitation that recombinant BDNF does not penetrate the blood-brain barrier adequately. Published rodent efficacy studies began appearing in indexed literature in the 2010s and continued into the early 2020s. As of the knowledge cutoff, no Western independent replication program and no sponsored clinical trial have been reported.

What the research says

Preclinical only. Rodent (rat and mouse) studies from the originating group demonstrate antidepressant-like activity in forced-swim and tail-suspension tests, anxiolytic effects in open-field and elevated-plus-maze assays, prevention of anhedonia under social defeat stress, and neuroprotection in models of ischemic stroke (transient middle cerebral artery occlusion), Alzheimer's-type pathology, and Parkinson's-like dopaminergic lesions. One stroke model study reported that GSB-106 at 0.1 mg/kg/day for 21 days prevented post-ischemic depressive-like behavior and memory impairment, and restored hippocampal CREB immunoreactivity in rats. A rabbit pharmacokinetics study of an oral tablet formulation reported relative bioavailability of approximately 160% compared to raw substance by HPLC-MS, suggesting a formulation advantage in absorption. No published human pharmacokinetic data, no human dose-ranging study, and no human efficacy or safety data exist. The entire published evidence base comes from one research program; independent replication has not been reported in indexed Western literature.

Reported effects

Antidepressant-like effects in rodent forced-swim and tail-suspension tests (preclinical only)
Anxiolytic-like effects in rodent open-field and elevated-plus-maze models (preclinical only)
Prevention of anhedonia under social defeat stress in mice (preclinical only)
Neuroprotection in rodent ischemic stroke models, with preservation of memory and mood-related behavior (preclinical only)
Attenuation of Alzheimer's-type and Parkinson's-like pathology markers in animal models (preclinical only)
Possible weak hypoglycemic effect noted incidentally in animal studies (clinical relevance unknown)
No human effects established; all above are rodent-model observations

Dosing & administration (informational)

Animal studies in the published literature used doses in the range of 0.1 to 1 mg/kg administered orally or intraperitoneally in rodents. These figures are provided for scientific reference only and cannot be extrapolated to human dosing - human pharmacokinetics, oral bioavailability in humans, CNS penetration, half-life, and therapeutic or toxic dose ranges are entirely uncharacterized. No human dosing information exists. Anyone considering this compound for any purpose should consult a licensed clinician; this entry does not constitute a dosing protocol or recommendation.

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

Safety & side effects

No human safety data of any kind exists; all safety observations are from rodent and rabbit studies
No serious adverse events were reported in published preclinical studies at doses tested
Long-term consequences of chronic TrkB agonism have not been characterized in any species at durations or doses relevant to human use
Potential weak blood glucose-lowering effect observed in animal models; implications for diabetic or prediabetic individuals are unknown
Theoretical risks of chronic neurotrophin-pathway overstimulation (e.g., effects on pain sensitization, tumor trophic support) have not been evaluated
Independent toxicology studies by researchers outside the originating institute have not been published
Sourcing from unregulated vendors introduces additional unknowns regarding purity, identity, and contaminants

Drug & supplement interactions

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Who should avoid it

Human use outside a properly approved clinical trial
Combination with antidiabetic medications without medical supervision (possible additive glucose-lowering)
Use by individuals with a history of neurotrophin-sensitive tumors (theoretical concern, uncharacterized)
Use during pregnancy or lactation (no safety data in any reproductive model)
Sourcing from unregulated vendors without independent certificate of analysis
Assuming rodent efficacy data predicts human outcomes

How it is commonly combined

No human stacking data exists. The compound has not been evaluated in combination with any other agent in published research. Stacking is not characterizable from available evidence.

Legal & regulatory. Not FDA-approved for any indication. No IND, Phase I, II, or III trial is listed on ClinicalTrials.gov. GSB-106 does not appear on any approved drug list (FDA, EMA, MHRA, Health Canada, TGA). It is an unapproved investigational compound not authorized for human use in the United States. No documented marketing authorization in Russia has been located in the public literature. Possession and use status varies by jurisdiction; it is not a scheduled substance under the US Controlled Substances Act as of the knowledge cutoff, but it is also not a lawful drug or dietary supplement under US law.

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Frequently asked questions

Has GSB-106 been tested in humans?

No. As of the knowledge cutoff, no published human pharmacokinetic, safety, or efficacy study exists, and no GSB-106 trial appears on ClinicalTrials.gov. All evidence is from rodent and rabbit preclinical studies conducted by the compound's developers.

What dose should I take?

No safe or effective human dose has been established. Human pharmacokinetics are entirely uncharacterized. Rodent study doses cannot be reliably converted to human equivalents for an unapproved compound with no human PK data. Consult a licensed clinician before considering any experimental compound.

Is GSB-106 legal to buy in the United States?

It is not a scheduled controlled substance under the CSA, but it is also not an approved drug or a legal dietary supplement. Its sale for human consumption would likely be unlawful under FDA regulations. Possession for personal use occupies a legal gray area, though enforcement priorities vary. Regulatory status should be independently verified for your jurisdiction.

How reliable is the existing preclinical evidence?

The animal model results are internally consistent across multiple rodent paradigms, which is encouraging from a scientific standpoint. However, substantially all published data originate from a single research group at one Russian institute. Independent replication by unaffiliated laboratories has not been reported in indexed literature, which limits confidence in the findings. Rodent antidepressant and neuroprotection models also have a historically poor record of predicting human clinical outcomes.

Is there a safer, proven alternative for the conditions GSB-106 is being researched for?

For depression and anxiety, multiple FDA-approved medications and evidence-based psychotherapies exist with extensive human safety and efficacy data (SSRIs, SNRIs, CBT, and others). For neuroprotection after stroke, established acute and rehabilitation interventions exist. None of these replicate a BDNF-mimetic mechanism, but they carry documented human evidence that GSB-106 does not.

Could GSB-106 become an approved drug?

It is a genuinely novel mechanistic approach - small-molecule TrkB agonism - and the preclinical rationale is scientifically coherent. However, the path from promising rodent data to approved human medicine fails the majority of the time, and GSB-106 has not yet entered even Phase I human testing. No timeline for clinical development has been announced in public sources.

References & further reading

PubMed: GSB-106 stroke depression post-ischemic BDNF mimetic TrkB Gudasheva 2023 (PMID 36597610)
PubMed: comparative pharmacokinetics GSB-106 tablet oral bioavailability rabbit HPLC-MS Gudasheva 2019 (PMID 31625065)
PubMed: GSB-106 antidepressant TrkB signaling PI3K Akt ERK dipeptide mimetic BDNF (search: GSB-106 TrkB antidepressant)
PubMed/PMC: low-molecular-weight BDNF mimetic GSB-106 neurotrophin dipeptide Gudasheva Seredenin (PMC7916338)
ClinicalTrials.gov: search 'GSB-106' - no registered trials found as of knowledge cutoff