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.
- Best for
- NCAM signaling mechanistic research, neuroprotection models (rodent only)
- Evidence grade
- Level D
- Confidence
- Low
- Starting point
- 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
- Not available as a commercial research peptide in most suppliers
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.