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P21

A CNTF-derived peptide that promotes neurogenesis and has shown promise in Alzheimer's disease research.

PreliminaryLimited Data

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This information is for educational purposes. Peptide therapy should be guided by a licensed healthcare provider. Connect with a Noho clinician

What is P21?

P21 is an 11-mer peptide derived from ciliary neurotrophic factor (CNTF) that has been modified to be small enough to cross the blood-brain barrier. It promotes neurogenesis (new neuron formation) in the hippocampus and has shown cognitive-enhancing effects in Alzheimer's disease animal models without the appetite-suppressing side effects of full-length CNTF.

Why People Talk About It

Hippocampal neurogenesis promotion

Preliminary

Cognitive enhancement in neurodegeneration models

Preliminary

Potential Alzheimer's disease therapeutic

Preliminary

How It Works

P21 helps your brain grow new neurons in the hippocampus (the memory center). It works by mimicking part of a natural brain growth factor (CNTF) while being small enough to cross from your blood into your brain.

Common Questions

Safety Information

Important Safety Notes

Common Side Effects

Limited human data availableGenerally well-tolerated in animal studies

Cautions

  • Not FDA-approved
  • No human clinical trials published
  • Long-term effects unknown

What We Don't Know

Human safety profile is entirely unknown. All data comes from preclinical animal studies.

Published Research

33 studies

The Role of Cadherin 17 (CDH17) in Cancer Progression via Wnt/β-Catenin Signalling Pathway: A Systematic Review and Meta-Analysis

Meta-AnalysisPMID: 41155133

Genetic susceptibility to retinoblastoma: A meta-analysis of single-nucleotide polymorphisms across global populations

Meta-AnalysisPMID: 41474558

Biomarkers for prognosis of meningioma patients: A systematic review and meta-analysis

Meta-AnalysisPMID: 38758750

Effects of nanomaterial exposure on telomere dysfunction, hallmarks of mammalian and zebrafish cell senescence, and zebrafish mortality

Meta-AnalysisPMID: 37673133

Is acute lymphoblastic leukemia with mature B-cell phenotype and KMT2A rearrangements a new entity? A systematic review and meta-analysis

Meta-AnalysisPMID: 33827367

Single nucleotide polymorphisms and the risk of developing a second primary cancer among head and neck cancer patients: a systematic literature review and meta-analysis

Meta-AnalysisPMID: 34078296

Genome-wide meta-analysis reveals novel susceptibility loci for thyrotoxic periodic paralysis

Meta-AnalysisPMID: 33105104

Clinical and Prognostic Implications of P21 (WAF1/CIP1) Expression in Patients with Esophageal Cancer: A Systematic Review and Meta-Analysis

Meta-AnalysisPMID: 31998417

A systematic review and narrative synthesis on the histological and neurobehavioral long-term effects of dexmedetomidine

Meta-AnalysisPMID: 30475445

Conservation and divergence of the p53 gene regulatory network between mice and humans

Meta-AnalysisPMID: 30710145

Association between MDM2 rs2279744, MDM2 rs937283, and p21 rs1801270 polymorphisms and retinoblastoma susceptibility

Meta-AnalysisPMID: 30544467

Risk Factors of Stomal Recurrence After Laryngectomy: A Systematic Review and Meta-analysis

Meta-AnalysisPMID: 28766955

p53-independent DUX4 pathology in cell and animal models of facioscapulohumeral muscular dystrophy

Meta-AnalysisPMID: 28754837

p21-activated kinase 1 (PAK1) expression correlates with prognosis in solid tumors: A systematic review and meta-analysis

Meta-AnalysisPMID: 27027431

Cervical Cancer Genetic Susceptibility: A Systematic Review and Meta-Analyses of Recent Evidence

Meta-AnalysisPMID: 27415837

Integration of TP53, DREAM, MMB-FOXM1 and RB-E2F target gene analyses identifies cell cycle gene regulatory networks

Meta-AnalysisPMID: 27280975

Association Between p21 Ser31Arg Polymorphism and Gastrointestinal Tract Tumor Risk: A Meta-analysis

Meta-AnalysisPMID: 24645745

Association of p21 3' UTR gene polymorphism with cancer risk: Evidence from a meta-analysis

Meta-AnalysisPMID: 26278624

Clinicopathologic and prognostic significance of p21 (Cip1/Waf1) expression in bladder cancer

Meta-AnalysisPMID: 26191193

Quantitative Assessment the Relationship between p21 rs1059234 Polymorphism and Cancer Risk

Meta-AnalysisPMID: 26028110

Effect and reporting bias of RhoA/ROCK-blockade intervention on locomotor recovery after spinal cord injury: a systematic review and meta-analysis

Meta-AnalysisPMID: 24297045

Systematic review and meta-analysis of tumor biomarkers in predicting prognosis in esophageal cancer

Meta-AnalysisPMID: 24206575

Quantitative assessment of the relationship between p21 Ser31Arg polymorphism and cervical cancer

Meta-AnalysisPMID: 23832542

Prognostic significance of several biomarkers in epithelial ovarian cancer: a meta-analysis of published studies

Meta-AnalysisPMID: 23595127

Association between p21 Ser31Arg polymorphism and cancer risk: a meta-analysis

Meta-AnalysisPMID: 21439247

P21 Ser31Arg polymorphism and cervical cancer risk: a meta-analysis

Meta-AnalysisPMID: 21430453

Meta-analysis of the relationship between p21 Ser31Arg polymorphism and lung cancer susceptibility

Meta-AnalysisPMID: 22009857

P21 codon 31 polymorphism associated with cancer among white people: evidence from a meta-analysis involving 78,074 subjects

Meta-AnalysisPMID: 21415438

The p21 Ser31Arg polymorphism and breast cancer risk: a meta-analysis involving 51,236 subjects

Meta-AnalysisPMID: 20349127

Polymorphisms in the BRCA1 and ABCB1 genes modulate menopausal hormone therapy associated breast cancer risk in postmenopausal women

Meta-AnalysisPMID: 19672706

Effects of a ciliary neurotrophic factor (CNTF) small-molecule peptide mimetic in an in vitro and in vivo model of CDKL5 deficiency disorder

PreclinicalPMID: 39592934

Enhancement of Neurogenesis and Memory by a Neurotrophic Peptide in Mild to Moderate Traumatic Brain Injury

PreclinicalPMID: 25255260

Neurotrophic peptides incorporating adamantane improve learning and memory, promote neurogenesis and synaptic plasticity in mice

PreclinicalPMID: 20600002

Always consult a qualified clinician

This information is for educational purposes. Peptide therapy should be guided by a licensed healthcare provider. Connect with a Noho clinician

Related Peptides

Quick Facts

Class
Neurotrophic Peptide
Evidence
Preliminary
Safety
Limited Data
Updated
Mar 2026
Citations
33PubMed

Also known as

P021CNTF-derived peptide

Tags

CognitiveNeuroprotectiveNeurogenesis

Related Goals

Evidence Score

Overall Confidence25%

Clinical Trials

View Clinical Trials

Links to ClinicalTrials.gov for reference. Listing does not imply endorsement.

Clinician Guided

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