FGL vs P21
A side-by-side research comparison of FGL and P21 across mechanism, dosing, half-life, benefits, side effects and research status.
Comparison table
| Attribute | FGL | P21 |
|---|---|---|
| Full name | FGL (NCAM-Derived Peptide) | P21 (CNTF-Derived Tetrapeptide) |
| Category | Cognitive & Nootropic | Cognitive & Nootropic |
| Status | Research compound | Research compound |
| Mechanism | Mimics NCAM FG loop interacting with FGFR1 to promote LTP, neurite outgrowth, neuronal survival, and presynaptic function enhancement. | Mimics CNTF neurogenesis-enhancing portion by increasing BDNF and activating PI3K/Akt. Inhibits LIF signaling to selectively promote neural stem cell proliferation. |
| Molecular weight | ~1,800 Da | ~450 Da |
| Half-life | 4-8 hours | 4-6 hours |
| Bioavailability | Moderate (SubQ, partial BBB crossing) | Moderate (crosses BBB) |
| Typical dose | 1-5 mg/kg (research) | 50-100 mcg/kg |
| Frequency | Daily or every other day | Daily |
| Route | Subcutaneous | Intranasal or Subcutaneous |
FGL reported benefits
- Synaptic plasticity
- LTP facilitation
- Memory improvement
- Neurotrophic effects
- FGFR activation
P21 reported benefits
- Hippocampal neurogenesis
- BDNF increase
- Cognitive enhancement
- BBB penetrant
- No appetite suppression
- Dendritic branching
Related comparisons
Research and educational reference only. Not medical advice.