P21 vs PE 22-28
A side-by-side research comparison of P21 and PE 22-28 across mechanism, dosing, half-life, benefits, side effects and research status.
Comparison table
| Attribute | P21 | PE 22-28 |
|---|---|---|
| Full name | P21 (CNTF-Derived Tetrapeptide) | PE 22-28 (Spadin-Derived TREK-1 Peptide) |
| Category | Cognitive & Nootropic | Cognitive & Nootropic |
| Status | Research compound | Research peptide (preclinical) |
| Mechanism | Mimics CNTF neurogenesis-enhancing portion by increasing BDNF and activating PI3K/Akt. Inhibits LIF signaling to selectively promote neural stem cell proliferation. | Selectively blocks the TREK-1 background potassium channel. TREK-1 inhibition enhances serotonergic signaling and rapidly increases synaptogenesis and neurogenesis, producing antidepressant-like effects faster than SSRIs in animal models. |
| Molecular weight | ~450 Da | ~ (7-residue peptide) |
| Half-life | 4-6 hours | Short (peptide; improved vs spadin) |
| Bioavailability | Moderate (crosses BBB) | Intranasal or injection (research) |
| Typical dose | 50-100 mcg/kg | Not established for humans |
| Frequency | Daily | Research only |
| Route | Intranasal or Subcutaneous | Intranasal or injection (research) |
P21 reported benefits
- Hippocampal neurogenesis
- BDNF increase
- Cognitive enhancement
- BBB penetrant
- No appetite suppression
- Dendritic branching
PE 22-28 reported benefits
- Rapid antidepressant effects (preclinical)
- Promotes neurogenesis and synaptogenesis
- TREK-1 channel blockade
- Neuroplasticity research interest
Related comparisons
Research and educational reference only. Not medical advice.