FGL

Areas of active research — not promised effects

Each tag links to other compounds with research into that goal. Research use only: these are areas of study, not human-use claims.

Related by research scope · open each to compare

FGL has no FDA-approved drug application and is not listed as a Category 1 compoundable substance under 503A bulk lists. It is not among the compounds subject to the February 2026 FDA Category-2 restrictions (fda19 flag: false). It may be legally manufactured and sold in the US only when explicitly labeled for research use only, with no human-use claims.

Transparent blend · bci-1.0 · never paid-placement

Primary name

FGL

Origin

FGL (also called FGLL or FG loop peptide) is a 15-amino-acid synthetic peptide corresponding to the FG loop region of the second fibronectin type III (F3) module of the neural cell adhesion molecule (NCAM). This sequence constitutes part of NCAM's binding interface with fibroblast growth factor receptor 1 (FGFR1) and was isolated to recapitulate NCAM's neurotrophic signaling without the full adhesion molecule scaffold.

Appearance

White to off-white lyophilized powder (typical for synthetic 15-mer peptide)

Solubility

Soluble in water and aqueous buffers; solubility facilitated by polar and charge…

Sequence not available in current seed.

Stability: Peptide bonds susceptible to proteolytic degradation in biological matrices; relative stability in buffered aqueous solutions at neutral pH. Avoid repeated free

Vial sizes

5 mg · 10 mg

Purity grades

>95% (HPLC) / >98% (HPLC)

Salt forms

Free base (primary)

• GHS hazard class on file
• PPE & spill response
• Disposal guidance
• Not-for-human-consumption posture

How much research exists, and of what maturity — never a verdict on whether it works.

Mechanism of action

• FGL binds to and induces phosphorylation of FGFR1, thereby activating downstream Ras–MAPK and PI3K–Akt signaling cascades that support neuronal survival, neurite outgrowth, and synaptogenesis
• By mimicking NCAM's interaction with FGFR1, the peptide promotes long-term potentiation (LTP), enhances presynaptic function, and stimulates proliferation and mobilization of endogenous neural stem cells in neurogenic niches
• Anti-inflammatory effects have also been observed, including modulation of IGF-1 and interferon-gamma pathways, and attenuation of HIF-1α dysregulation under ischemic conditions
• In NCAM-deficient rodents, FGL partially restores FGFR-mediated phosphorylation, suggesting it can substitute for endogenous NCAM–FGFR1 coupling in conditions of reduced NCAM expression

Pharmacokinetics (ADME)

Half-life

Approximately 4–6 hours after subcutaneous administration in preclinical models; dose-dependent plasma exposure observed in a phase I intranasal human study (PMID 17375985 — not in compound topPmids list; see flags)

Clearance

Rapid systemic clearance; CSF penetration confirmed in rats within 10 minutes of subcutaneous injection and sustained for up to 5 hours in animal studies

PK–PD note: Intranasal route showed dose-related plasma exposure in healthy volunteers (25, 100, 200 mg doses); brain access inferred from CSF measurements in translational animal work. No formal PK data derived …

Reading the evidence

• Evidence quality and gaps vary by application — see the cited grades above.
• Indexed-article counts span all evidence tiers, not only completed human trials.
• No first-party human-dosing, efficacy, or benefit claims are made here.

Key reviews & evidence-gap sources

• Li S, Bock E, Berezin V. Neuritogenic and Neuroprotective Properties of Peptide Agonists of the Fibroblast Growth Factor Receptor. Int J Mol Sci. 2010;11(6):2291-2305. — Review of FGFR agonist peptides including FGL; summarizes in vitro/in vivo evidence and downstream signaling (FRS2α, ShcA, PLCγ, Akt, Erk1/2)
• CORDIS NEUROFGL (FP7, Grant 278006) Final Report — Development of a novel FGL therapy and translational tests for regenerative treatment of neurological disorders — EU-funded project (2012-2014); FGLs demonstrated safe/well-tolerated in humans; final clinical trial could not be completed within project period due to toxicology delays
• Anand R, Seiberling M, Kamtchoua T, Pokorny R. Tolerability, safety and pharmacokinetics of the FGLL peptide...following intranasal administration in healthy volunteers. Clin Pharmacokinet. 2007;46(4):351-8. — Phase I safety/PK study in 24 healthy male volunteers; single intranasal dose; no efficacy endpoint — not an RCT

No registered human trials found for this compound.

Status

No registered trials found

Summary (literature)

In the only available human exposure data (a phase I intranasal study; PMID 17375985, outside the compound's gathered PMID set), single doses up to 200 mg in 24 healthy male volunteers were well tolerated with no clinically notable ECG, vital sign, or laboratory abnormalities; mi…

WADA status

Not specifically listed on the WADA Prohibited List. FGL is not a growth hormone secretagogue, anabolic agent, or known performance-enhancing substance under cu…

Dominant research route: Intranasal (IN)

Pharmacokinetics in rats (CSF and blood plasma); cited in mouse kindling efficacy study

Bioavailability: FGL detectable in rat cerebrospinal fluid within 10 min following SC administration, with stable concentrations up to 5 h; also detected in blood plasma. FGL rapidly penetrated into blood and CSF after SC administration and remained detectable for up to 5 hours.

SC is the most characterized parenteral route in preclinical rodent models. ICV (intracerebroventricular) infusion was also studied in rats for LTP/plasticity experiments but does not map to a standard route abbreviation. No human SC data located.

Phase I first-in-human tolerability/safety/PK study (24 healthy male volunteers, 25/100/200 mg single ascending intranasal doses); preclinical in rats, dogs, monkeys

Bioavailability: In humans, quantifiable plasma FGL_L observed up to 1 h (100 mg dose) and up to 4 h (200 mg dose); 25 mg dose undetectable at all timepoints. Mean Cmax 0.52 ng/mL (100 mg) and 1.38 ng/mL (200 mg); mean AUC_24 1.27 ng·h/mL (100 mg) and 4.05 ng·h/mL (200 mg). Preclinical studies in rats, dogs, and monkeys demonstrated exposure in plasma and CSF after intranasal administration with no systemic toxicity.

This is the only route studied in humans (open-label Phase I, not randomized). Intranasal is the dominant research route. A hyaluronate–FGL conjugate was later developed to improve enzymatic stability and nose-to-brain delivery efficiency in a rat hypoxic-ischemic encephalopathy model.

Animal & human figures are kept visibly separate so studied animal doses are never misread as human guidance.

Sorted A–Z by vendor — never by price

No longitudinal price series retrieved; vendor pages are static snapshots. Peptide Sciences shutdown is a supply-side event but no directional price movement observed.

Researched storefront prices, bucketed

p25 $6.45 · median $9.90 · p75 $10.95 · 6 researched vendors

Legit, COA-backed band: $3.00–$12.00/mg.

Value rule: don't just buy the cheapest — a price under $3/mg is a red flag. Pair price with COA and independent-test grade.

Estimated cost of research (10 mg)

Vial (best researched price)

$30

Bacteriostatic water (generic estimate)

$6

Syringes / supplies (generic estimate)

$12

What each test proves — general guidance, plus this compound's researched purity data

Purity on the current market (researched)

≥98–99% (vendor-reported, third-party HPLC COA per batch; no independent aggregate lab-test dataset located for FGL specifically)

Independent labs cited for this compound

No FGL-specific recalls, FDA enforcement actions, warning letters, or counterfeit/seizure events were found in FDA enforcement databases, Janoshik public test aggregates, or reputable vendor COA ledgers. FGL (NCAM-derived FGFR1 agonist, CAS 499993-62-3) is a niche research-use-only peptide with no documented compound-specific regulatory actions as of search date.

Buyer red-flag checklist

• FGL is a niche 15-amino-acid research peptide with no FDA-approved human use and no completed human RCTs located in retrieved sources.
• Purity figures (≥98–99%) are vendor-reported via per-batch COAs; no independent aggregate third-party testing dataset (Janoshik/MZ Biolabs/Finnrick) was retrievable for FGL specifically.
• Sold as 'research use only' / 'lab use only' by multiple vendors while simultaneously marketed with cognitive-enhancement, neuroprotective, and brain-repair claims — a classic RUO/marketing mismatch red flag.
• No compound-specific FDA enforcement, recall, seizure, or counterfeit event found — absence of enforcement does not equal verified quality; the compound is largely outside routine surveillance.
• Janoshik public test ledger (public.janoshik.com) returned HTTP 403 / no FGL-specific entries in search, limiting independent verification of vendor purity claims.

GMP vs research-grade: the chemistry (SPPS + HPLC + MS) is identical — the difference is the quality system.

Underdosing / mislabeling: No independent lab-test aggregates (Janoshik public ledger, MZ Biolabs, Finnrick) returned FGL-specific results; underdosing prevalence cannot be quantified from retrieved sources.

• FDA Import Alert 66-41 'Detention Without Physical Examination of Unapproved New Drugs Promoted In The U.S.' (published 06/24/2026) authorizes DWPE of unapproved new drug products. This is a general alert covering unapproved new drugs marketed with disease/structure-function claims; it is NOT FGL-specific and does not name FGL or its CAS (499993-62-3) on the Red List in the retrieved text. Research peptides sold without drug claims generally fall outside this alert, but vendors promoting FGL with cognitive/neuroprotective treatment claims could be subject to it.66-41
• An RUO label is not an import exemption — CBP judges actual intended use.
• Lyophilized powder is ambient-stable in transit; temperature control needed for > 7-day transit.
• US-warehouse vendors dodge import scrutiny — they cost more but ship more reliably.

Every item dated & sourced

FGL (NCAM-derived FG-loop peptide) is not specifically named on the WADA Prohibited List. As an unapproved substance with no marketing authorization from any major regulator, it could theoretically fall under S0 (Non-Approved Substances) if used in sport, but it is not individually listed.

No granted patents identified in current seed. Composition-of-matter coverage is limited given the peptide's synthetic origin.

• IACUC / IRB research context
• RUO buyer responsibilities & documentation
• Veterinary / alternative-use where lawful
• Jurisdiction-aware "who may lawfully obtain"

What people discuss

Reported concerns — discussion, not established effects

Reading caveats

• small-n anecdotal self-experimentation reports
• enthusiast-forum hype language
• vendor-affiliated content present
• no controlled human efficacy data

Manually researched from reddit, youtube— theme weights are research estimates, not live counts; aggregated & de-identified. No individual posts, quotes, or usernames are ever shown.

Relative research / market volume — populated once the activity stream is wired

Inline tooltips for lyophilized, RUO, EU/mg, SPPS, 503A and more.

Toggle plain-language ↔ scientific in the header.

• How to read a COA
• Free base vs acetate
• Understanding evidence grades

Synthetic 15-amino-acid NCAM-mimetic peptide that activates FGFR1 signaling, promoting synaptic plasticity and neuroprotection in preclinical models. Approximately 61 articles are indexed (literature last scanned 2026-05-29). US regulatory status: Research Use Only; not FDA-approved, not on 503A/503B bulk lists. Research use only.

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