Peptide Handbook
Cognitive Peptides

P21

CNTF-Derived Neurogenic Tetrapeptide

Updated April 14, 2026

What is P21?

A synthetic tetrapeptide derived from the active region of ciliary neurotrophic factor (CNTF), designed to mimic CNTF's neurogenic effects without binding its receptor. P21 promotes neurogenesis in the hippocampal dentate gyrus and subventricular zone by increasing BDNF expression and inhibiting leukemia inhibitory factor (LIF) signaling. Preclinical studies in Alzheimer's disease models show improved spatial memory and reduced tau hyperphosphorylation.

Research Profile

Structure 4 amino acids (~330 Da) — CNTF-derived epitope
Targets BDNF upregulation, LIF inhibition, dentate gyrus neurogenesis
Research Focus Adult neurogenesis, Alzheimer's disease models, hippocampal plasticity, cognitive rescue
Reconstitution Bacteriostatic water — 1 mg/mL
Stability 21 days at 2–8°C
Key distinction: Mimics CNTF neurogenic activity without receptor binding — the smallest peptide capable of promoting adult hippocampal neurogenesis through BDNF-dependent mechanisms.

Published Research

[1] Bolognin D et al. An experimentally driven approach to develop a small peptide with CNTF-like neurotrophic activity. PLoS One 2014;9:e89283 — PubMed 24586660
[2] Li B et al. P21 peptide rescues cognition and normalizes tau pathology in Alzheimer's disease mouse model. Neurotherapeutics 2015;12:553-563 — PubMed 25916396
Research Use Only. All products sold by Lumen Peppers are intended solely for in vitro research and laboratory purposes. They are not drugs, supplements, or foods. Nothing on this page constitutes medical advice. Researchers are responsible for compliance with all applicable regulations. Last updated: April 14, 2026.

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