Cortexin vs P21
A side-by-side research comparison of Cortexin and P21 across mechanism, dosing, half-life, benefits, side effects and research status.
Comparison table
| Attribute | Cortexin | P21 |
|---|---|---|
| Full name | Cortexin (Polypeptide Brain Extract) | P21 (CNTF-Derived Tetrapeptide) |
| Category | Cognitive & Nootropic | Cognitive & Nootropic |
| Status | Research compound (used clinically in some regions) | Research compound |
| Mechanism | Provides a blend of neuropeptides and neurotrophic factors thought to support neuronal metabolism, reduce oxidative stress, balance excitatory/inhibitory neurotransmission, and promote neuroprotection and repair. | Mimics CNTF neurogenesis-enhancing portion by increasing BDNF and activating PI3K/Akt. Inhibits LIF signaling to selectively promote neural stem cell proliferation. |
| Molecular weight | Mixture (peptides <10 kDa) | ~450 Da |
| Half-life | Varies by component | 4-6 hours |
| Bioavailability | Intramuscular injection | Moderate (crosses BBB) |
| Typical dose | ~10 mg per day (course-based) | 50-100 mcg/kg |
| Frequency | Once daily | Daily |
| Route | Intramuscular injection | Intranasal or Subcutaneous |
Cortexin reported benefits
- Neuroprotection
- Cognitive and memory support
- Used in stroke/TBI recovery (regional clinical use)
- Antioxidant effects
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.