FGL
Also known as: FG Loop Peptide, NCAM Mimetic
NCAM-Derived Peptide | Synaptic Plasticity & Neuroprotection
Overview
FGL is a synthetic peptide derived from the second fibronectin type III module of neural cell adhesion molecule (NCAM). It mimics the interaction between NCAM and fibroblast growth factor receptor 1 (FGFR1), activating downstream signaling cascades that promote synaptic plasticity, neurogenesis, and neuroprotection. Research has primarily been conducted in animal models, where FGL has shown promise for cognitive enhancement, stroke recovery, and neurodegenerative disease models.
Key benefits
- Activates FGFR1 to promote synaptic plasticity
- Stimulates hippocampal neurogenesis
- Provides neuroprotection against excitotoxic and ischemic injury
- Enhances long-term potentiation (LTP) in preclinical models
- Potential cognitive enhancement via NCAM-mimetic signaling
Mechanism of action
FGL binds to and activates FGFR1, triggering receptor autophosphorylation and downstream signaling through the MAPK/ERK and PI3K/Akt pathways. This activation promotes long-term potentiation (LTP), enhances synaptic plasticity, stimulates neurogenesis in the hippocampus, and provides neuroprotective effects against excitotoxicity and oxidative stress.
Molecular data
- Type
- Synthetic peptide derived from the second fibronectin type III module of NCAM
- Half-life
- Not well characterized
Indications
What the research community uses this compound for, with self-reported effectiveness.
Cognitive
Memory and Learning
ModerateEnhances memory consolidation and spatial learning in animal models through FGFR1-mediated synaptic plasticity.
Cognitive Decline
ModeratePreclinical evidence suggests potential to counteract age-related cognitive decline via neurogenesis and synaptic support.
Neuroprotection
Stroke Recovery
ModerateAnimal studies demonstrate reduced infarct volume and improved functional outcomes following ischemic injury.
Neurodegenerative Disease Models
ModerateShows protective effects in preclinical models of Alzheimer's disease and other neurodegenerative conditions.
Neuroplasticity
Synaptic Plasticity
ModeratePromotes long-term potentiation and strengthens synaptic connections through FGFR1 activation.
Neurogenesis
ModerateStimulates the generation of new neurons in the hippocampus in animal models.
Dosing protocols
Common protocols by delivery method. Adjust the curve below to model accumulation in your own cycle.
Injectable
Subcutaneous injection is the primary administration route studied in preclinical research. Human pharmacokinetic data is very limited.
| Protocol | Dose | Frequency | Route / duration |
|---|---|---|---|
| Cognitive support (research protocol) | 100-200mcg | 1x daily | SubQ |
Preparation
You will need
- FGL lyophilized powder
- Bacteriostatic water
- Insulin syringes (29-31 gauge)
- Alcohol swabs
Steps
- Allow vial to reach room temperature
- Clean vial top with alcohol swab
- Inject bacteriostatic water slowly down the side of the vial
- Gently swirl until fully dissolved -- do not shake
- Draw desired dose into insulin syringe
- Inject subcutaneously in the abdomen or thigh
- Refrigerate reconstituted solution and use within 4 weeks
Work out the water volume and syringe units in the reconstitution calculator →
Interactions
Pairwise interactions with other compounds you might be cycling — the same data behind the cycle builder's safety check.
Semax
SynergisticBoth support neuroplasticity and neuroprotection through complementary mechanisms -- FGFR1 activation (FGL) and BDNF upregulation (Semax).
Dihexa
CompatibleDifferent mechanisms of cognitive support; Dihexa acts via HGF/c-Met while FGL activates FGFR1.
Cerebrolysin
CompatibleBoth provide neurotrophic support through different pathways; no known adverse interactions.
Timeline
Typical week-by-week effects reported in clinical and observational data.
- Week 1
Limited immediate subjective effects expected; molecular-level FGFR1 activation begins
- Week 2-3
Potential subtle improvements in cognitive clarity and focus based on preclinical timelines
- Week 4+
Cumulative neuroplastic and neuroprotective effects may become more apparent with continued use
Safety
Reported adverse effects, contraindications, and what to monitor on cycle.
Common side effects
- Injection site reactions (redness, mild swelling, irritation)
Stop signs — stop and seek advice
- Signs of allergic reaction (rash, difficulty breathing, swelling)
- Persistent or worsening injection site reactions
- Unusual neurological symptoms (severe headache, dizziness, vision changes)
Contraindications
- Pregnancy or breastfeeding
- Known peptide or NCAM-related compound allergies
- Very limited human safety data -- use with caution under medical supervision
Monitoring
- Start at the low end of the dose range (100mcg) to assess tolerance
- Monitor injection sites for reactions
- Human pharmacokinetic and safety data is extremely limited -- proceed conservatively
Quality checks
What a legitimate product looks like, what should give pause, and what should make you stop.
Good signs
- White to off-white lyophilized powder
- Complete dissolution upon reconstitution
- Third-party purity testing (>95% purity)
- Proper cold chain shipping
Warning signs
- Injection site irritation
- Very limited human safety data available
Stop signs — don't use
- Cloudy or discolored solution after reconstitution
- Visible particles or aggregates
- Powder that does not dissolve fully
References
Primary literature and clinical-trial data informing this entry.
A Peptide Agonist of the Neural Cell Adhesion Molecule NCAM, FGL, Enhances Synaptogenesis and Memory in Rats
Bhatt DK, Bhatt SS, et al. · European Journal of Neuroscience · 2009
FGL enhanced synaptogenesis in the hippocampus and improved spatial memory performance in rats, demonstrating the peptide's ability to promote functional synaptic plasticity.
FGL, a Neural Cell Adhesion Molecule-Derived Peptide, Promotes Recovery in a Rat Model of Stroke
Bhatt DK, et al. · European Journal of Neuroscience · 2013
FGL treatment reduced infarct volume and improved functional recovery following middle cerebral artery occlusion in rats, supporting its neuroprotective potential in ischemic stroke.
The FGL Peptide Derived from NCAM Acts as a Neurotrophic Factor and Promotes Neurite Outgrowth and Survival of Neurons
Neiiendam JL, Bhatt DK, Bhatt SS, et al. · Journal of Neurochemistry · 2004
FGL promoted neurite outgrowth and neuronal survival through activation of FGFR1 and downstream signaling pathways, establishing the mechanistic basis for its neurotrophic properties.
Enhancement of Long-Term Potentiation and Memory by the NCAM-Derived Peptide FGL
Bhatt DK, et al. · Neuropharmacology · 2008
Systemic administration of FGL enhanced long-term potentiation in the dentate gyrus and improved associative memory in aged rats, demonstrating cognitive benefits through FGFR1-mediated mechanisms.
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