FGL vs Substance P
A detailed comparison to help you understand the differences and choose the right peptide for your research goals.
FGL
FGL (FG Loop) is a synthetic peptide that mimics the neural cell adhesion molecule (NCAM) FG loop region. It promotes neuroplasticity and has shown cognitive-enhancing effects in research.
Full details →Substance P
Substance P is an 11-amino acid neuropeptide involved in pain transmission, inflammation, and various neurological processes. While not used therapeutically itself, understanding it is crucial for pain research.
Full details →Side-by-Side Comparison
| Aspect | FGL | Substance P |
|---|---|---|
| Dose Range | 500 mcg–1 mg | 35 mcg–350 mcg |
| Frequency | 1x daily | 1x daily |
| Cycle Length | 4–8 weeks | 1 weeks |
| Route | intranasal | subcutaneous |
| Mechanism | Binds to FGFR1 (fibroblast growth factor receptor 1) to activate downstream signaling cascades that promote neurite outgrowth, synaptic plasticity, and neuronal survival. | Binds primarily to NK1 receptors to transmit pain signals from peripheral nerves to the CNS. Also promotes inflammation, causes vasodilation, and stimulates immune cells. |
| Typical Dosage | Research protocols have used subcutaneous doses ranging from 1-10mg. Intranasal administration also studied. Optimal dosing not established. | Not used as a therapeutic agent. NK1 receptor antagonists (blocking Substance P) are used clinically for chemotherapy-induced nausea. |
| Administration | Subcutaneous injection or intranasal administration. Research compound with limited human dosing data. | Research compound only. Therapeutic applications focus on blocking rather than administering Substance P. |
| Side Effects | Limited human data available. Animal studies show good tolerability. | Administration would cause pain, inflammation, and neurogenic responses. Not given therapeutically. |
| Best For |
What They Have in Common
FGL, Substance P are both commonly used for:
Which Has Stronger Evidence?
- Cognitive Performance: FGL has stronger research support.
| Goal | FGL | Substance P |
|---|---|---|
| Cognitive Performance | medium | low |
Key Studies
Substance P
- Revisiting the role of Substance P and CGRPα.
eLife, 2025
- Biochemistry, Substance P.
2023
- Substance P-Friend or Foe.
Journal of clinical medicine, 2022
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