FGL Peptide Evidence Guide
Evidence for FGL Peptide is too preliminary to support a research protocol with confidence. Data consists of rodent neuroprotection studies with no human trials. NCAM-pathway biology is scientifically interesting but FGL has not advanced to clinical investigation. Cerebrolysin is the better-evidenced starting point for neuroprotective research in this library.
Our Take
Evidence for FGL Peptide is too preliminary to support a research protocol with confidence. Data consists of rodent neuroprotection studies with no human trials. NCAM-pathway biology is scientifically interesting but FGL has not advanced to clinical investigation. Cerebrolysin is the better-evidenced starting point for neuroprotective research in this library.
- Evidence context
- NCAM signaling mechanistic research, neuroprotection models (rodent only)
- Evidence grade
- Level D
- Confidence
- Low
- Reference context
- Reported research reference: No established human protocol
Benefits and Evidence
- Synaptic Plasticity Enhancement: Level D, mostly non-human evidence - FGL enhances long-term potentiation (LTP) in hippocampal slice preparations and increases dendritic spine density in cortical and hippocampal neurons in vivo.
- Memory Consolidation: Level D, mostly non-human evidence - Rodents treated with FGL demonstrate improved performance in passive avoidance, Morris water maze, and social recognition memory paradigms.
- Neuroprotection: Level D, mostly non-human evidence - FGL treatment reduces neuronal death in models of excitotoxicity and ischemia, potentially through FGFR1-mediated activation of PI3K/Akt survival signaling.
Side Effects and Warnings
- No significant adverse effects reported in animal studies
- Potential for FGFR-mediated proliferative effects at high doses
- Unknown human safety profile
- No human studies have been conducted
- FGFR1 activation could theoretically promote cell proliferation in susceptible tissues
- Long-term effects of chronic FGFR1 stimulation in the brain are unknown
- No established clinical product or routine therapeutic access
Research Dosage References
- <strong>Subcutaneous (animal studies)</strong> - 5-10 mg/kg - Single dose or short course (1-5 days) - Dosing from published rodent studies. Subcutaneous FGL reaches the brain and produces measurable cognitive effects. No human dosing established.
Mechanism of Action
FGL binds to immunoglobulin-like domains 2-3 of FGFR1, mimicking the natural NCAM-FGFR1 interaction. This activates FGFR1 tyrosine kinase activity, triggering PLCgamma/DAG/PKC and Ras/MAPK/ERK signaling cascades. Downstream effects include: (1) Enhanced CREB phosphorylation and BDNF transcription in hippocampal neurons; (2) Increased presynaptic vesicle recycling and neurotransmitter release probability; (3) Promotion of dendritic spine formation and stabilization; (4) Enhanced long-term potentiation (LTP) at hippocampal CA1 synapses. These molecular effects translate to improved spatial and associative memory in animal models.
Legal Status
Research compound only; not approved for human use.
Primary Sources
- A neural cell adhesion molecule-derived peptide, FGL, enhances memory in rats. Neuroscience, 2008.
- Modulation of presynaptic function by the NCAM mimetic peptide FGL. Neurochemistry International, 2009.
- NCAM mimetic peptides: structure, activity, and therapeutic potential. Neurochemical Research, 2010.
Quick Answers
Where is the strongest evidence for FGL Peptide?
Evidence for FGL Peptide is too preliminary to support a research protocol with confidence. Data consists of rodent neuroprotection studies with no human trials. NCAM-pathway biology is scientifically interesting but FGL has not advanced to clinical investigation. Cerebrolysin is the better-evidenced starting point for neuroprotective research in this library. Evidence context: NCAM signaling mechanistic research, neuroprotection models (rodent only).
What are the main side effects of FGL Peptide?
FGL Peptide side effects and warning signals include No significant adverse effects reported in animal studies, Potential for FGFR-mediated proliferative effects at high doses, Unknown human safety profile, No human studies have been conducted, and FGFR1 activation could theoretically promote cell proliferation in susceptible tissues.
What evidence level is FGL Peptide?
FGL Peptide is rated Level D; the listed research status is Preclinical.