FGL
Research onlyFGL is classified under nootropic & regulatory peptides, sold for research use only and not approved for human consumption.
Read the full guide: what the research shows on FGL →What the research says
Aggregated from the cited literature below. We summarize sources — we don't author claims.
FGL (FG loop), a neural cell adhesion molecule (NCAM)-derived mimetic peptide, has been investigated in multiple contexts including hippocampal synaptic plasticity, neuroinflammation/glial responses, and neural stem cell (NSC) proliferation/mobilization. A separate, unrelated marker named FGL-1 is also discussed in lung neuroendocrine carcinoma and in Sjögren disease immune regulation in the provided sources.
Mechanism (as reported)
In provided studies, FGL has been described as a NCAM mimetic peptide that binds to FGFR-1 and facilitates hippocampal long-term potentiation (LTP) in vivo; anti-inflammatory effects have been associated with CD200 and IL-4/ERK signaling in glial/neuron systems. Another provided report describes distinct receptor mediation for NSC differentiation outcomes after FGL exposure.
Key findings (each cites a source)
- A study reported that FGL facilitates the induction and maintenance of long-term potentiation (LTP) in the dentate gyrus in vivo, without altering basal synaptic transmission at perforant path–dentate gyrus synapses, and it also modified heterosynaptic plasticity at neighboring synapses. [PMID 21508096]
- A study reported that FGL intracerebroventricular infusion in awake animals confirmed its facilitating effect on LTP for up to 24 hours. [PMID 21508096]
- Research investigated whether FGL influences neurogenesis associated with LTP, and reported that their data suggested FGL could alter neurogenesis linked to LTP. [PMID 21508096]
- A study reported that FGL attenuates LPS-induced changes in glial activation markers and pro-inflammatory cytokines in a CD200-dependent manner, with stronger LPS effects and loss of FGL attenuation observed in CD200-deficient cells. [PMID 23337536]
- A study reported that FGL acts as an anti-inflammatory agent in aged rats, attenuating increased markers of activated microglia, increased IL-1beta expression, and impairment in long-term potentiation (LTP). [PMID 18468731]
- A study reported that in the context of FGL anti-inflammatory effects, neuronal CD200 expression was decreased with age and suggested FGL’s suppression of microglial activation was linked to stimulation of neuronal CD200. [PMID 18468731]
- A study reported that FGL enhanced IL-4 release from glial cells and that IL-4 enhanced neuronal CD200 in vitro, with the CD200 increase described as reliant on IL-4-induced ERK signaling. [PMID 18468731]
- Research investigated the biocompatibility of self-assembled FGL peptide nanofibers (FGL-PA) with neural stem cells in vitro and reported that FGL-PA formed a nano-fiber gel and promoted NSC proliferation at certain tested concentrations, with reported changes in differentiation toward neurons under differentiation conditions. [PMID 19068609]
- A study reported that FGL mobilizes NSCs, with FGL increasing NSC proliferation in vitro and increasing proliferative activity in vivo in the subventricular zone (SVZ), supported by PET imaging using [(18)F]-fluoro-L-thymidine. [PMID 24817672]
- A study reported that during differentiation, NCAM promoted neurogenesis whereas FGL induced an oligodendroglial phenotype, and that astrocytic differentiation was neither affected by NCAM nor FGL; the differentiation effects were described as mediated through different receptors. [PMID 24817672]
Independent test grades
No independent third-party test data is available for FGL yet. Our test grades are aggregated from Finnrick, which independently tests a subset of research peptides — many approved drugs and newer or niche compounds aren't covered.
Research literature (13)
Consolidated from PubMed — each links to the original record.
- Regulatory Role of FGL-1 in Interorgan Communication by Controlling T Cell Homeostasis During the Onset of Sjögren Disease.
Otsuka K, Ushio A, Nagao R, Matsuzawa S, Arakaki R, Fukuta K · Arthritis & rheumatology (Hoboken, N.J.) · 2025 · PMID 40395191
- Integrated molecular and clinical characterization of pulmonary large cell neuroendocrine carcinoma.
Nassar AH, Kim C, Adeyelu T, Bou Farhat E, Abushukair H, Rakaee M · Nature communications · 2025 · PMID 40830141
- Peptides Acting as Cognitive Enhancers.
Asua D, Bougamra G, Calleja-Felipe M, Morales M, Knafo S · Neuroscience · 2018 · PMID 29030286
- Impact of the neural cell adhesion molecule-derived peptide FGL on seizure progression and cellular alterations in the mouse kindling model.
Zellinger C, Salvamoser JD, Seeger N, Russmann V, Potschka H · ACS chemical neuroscience · 2014 · PMID 24456603
- The synthetic NCAM mimetic peptide FGL mobilizes neural stem cells in vitro and in vivo.
Klein R, Blaschke S, Neumaier B, Endepols H, Graf R, Keuters M · Stem cell reviews and reports · 2014 · PMID 24817672
- The neural cell adhesion molecule-derived peptide, FGL, attenuates lipopolysaccharide-induced changes in glia in a CD200-dependent manner.
Cox FF, Berezin V, Bock E, Lynch MA · Neuroscience · 2013 · PMID 23337536
- A neural cell adhesion molecule-derived peptide, FGL, attenuates glial cell activation in the aged hippocampus.
FAQ
- What is FGL?
- FGL is classified under nootropic & regulatory peptides, sold for research use only and not approved for human consumption. Research goals associated with it include cognitive & mood.
- Is FGL FDA-approved?
- No. FGL is sold for research use only and is not approved for human consumption.
- What does the research on FGL say?
- peptideone aggregates 13 references from PubMed for FGL. The summary on this page digests them with citations; we summarize sources and make no efficacy claims.