FGL — EU research guide.

What is FGL?

FGL (EVYVVAENQQGKSKA) is a linear peptide taken from the second fibronectin type III module of NCAM, the part that binds fibroblast growth factor receptor 1 (FGFR1). It was developed by the Berezin/Bock group at the University of Copenhagen. It is proposed to activate FGFR1 in a way that differs from FGF1 itself, which in cell cultures is linked to neurite outgrowth, neuronal survival and stronger presynaptic function. The literature also uses FGLL and FGLS, which are different derivatives, not the same molecule. The CAS number shown (499993-62-3) comes from vendor listings only and was not confirmed in a registry, and it is not confirmed that it refers to the plain 15-mer; the molecular weight is calculated from the sequence.

What does the research show?

All FGL data that could be verified come from animals or cell cultures. In rats, injection into the brain ventricles right after training was reported to give a long-lasting memory improvement, with more synapses in hippocampal cultures (Cambon 2004), and FGL was reported to protect hippocampal CA1 neurons after ischaemia in vitro and after global ischaemia in rats (Skibo 2005). Secher et al. (2006) reported faster early sensorimotor development in rat pups and longer social memory in adult rats, with the peptide detectable in blood and CSF for up to 5 hours; no elimination half-life was found. Structural synapse changes were reported in 22-month-old rats (Popov 2008), and less Abeta25-35-induced pathology and cognitive impairment (Klementiev 2007). The only human data found concern the derivative FGLL: a phase I study in 24 healthy men (single intranasal doses) reported good tolerability, adverse events in 3 of 24 subjects (13%) and a Cmax of 0.52 and 1.38 ng/mL at the two higher dose levels (Anand 2007). No efficacy data in patients exist, and a 2008 Neurochem Res paper on NCAM mimetic peptides and spine morphology was withdrawn.

EU legal status

No marketing authorisation for FGL was found, so it is not an authorised medicine in the EU as far as could be established; the EMA register was not queried directly, so this means 'none found', not a formal confirmation. The derivatives FGLL and FGLs (Enkam Pharmaceuticals, Denmark) reached only phase I; according to a CORDIS project report, the planned phase II study of FGLs was not finished by the end of the EU-funded NeuroFGL project (December 2014) because of a shortage of raw material. FGL is not named on the 2026 WADA Prohibited List, but the broad S2.3 clause on growth factor modulators exists; this was read on a national copy of the list only.