P21
A CNTF-derived peptide that promotes neurogenesis and has shown promise in Alzheimer's disease research.
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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
PreliminaryCognitive enhancement in neurodegeneration models
PreliminaryPotential Alzheimer's disease therapeutic
PreliminaryHow 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
Common Side Effects
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 studiesThe Role of Cadherin 17 (CDH17) in Cancer Progression via Wnt/β-Catenin Signalling Pathway: A Systematic Review and Meta-Analysis
Genetic susceptibility to retinoblastoma: A meta-analysis of single-nucleotide polymorphisms across global populations
Biomarkers for prognosis of meningioma patients: A systematic review and meta-analysis
Effects of nanomaterial exposure on telomere dysfunction, hallmarks of mammalian and zebrafish cell senescence, and zebrafish mortality
Is acute lymphoblastic leukemia with mature B-cell phenotype and KMT2A rearrangements a new entity? A systematic review and meta-analysis
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
Genome-wide meta-analysis reveals novel susceptibility loci for thyrotoxic periodic paralysis
Clinical and Prognostic Implications of P21 (WAF1/CIP1) Expression in Patients with Esophageal Cancer: A Systematic Review and Meta-Analysis
A systematic review and narrative synthesis on the histological and neurobehavioral long-term effects of dexmedetomidine
Conservation and divergence of the p53 gene regulatory network between mice and humans
Association between MDM2 rs2279744, MDM2 rs937283, and p21 rs1801270 polymorphisms and retinoblastoma susceptibility
Risk Factors of Stomal Recurrence After Laryngectomy: A Systematic Review and Meta-analysis
p53-independent DUX4 pathology in cell and animal models of facioscapulohumeral muscular dystrophy
p21-activated kinase 1 (PAK1) expression correlates with prognosis in solid tumors: A systematic review and meta-analysis
Cervical Cancer Genetic Susceptibility: A Systematic Review and Meta-Analyses of Recent Evidence
Integration of TP53, DREAM, MMB-FOXM1 and RB-E2F target gene analyses identifies cell cycle gene regulatory networks
Association Between p21 Ser31Arg Polymorphism and Gastrointestinal Tract Tumor Risk: A Meta-analysis
Association of p21 3' UTR gene polymorphism with cancer risk: Evidence from a meta-analysis
Clinicopathologic and prognostic significance of p21 (Cip1/Waf1) expression in bladder cancer
Quantitative Assessment the Relationship between p21 rs1059234 Polymorphism and Cancer Risk
Effect and reporting bias of RhoA/ROCK-blockade intervention on locomotor recovery after spinal cord injury: a systematic review and meta-analysis
Systematic review and meta-analysis of tumor biomarkers in predicting prognosis in esophageal cancer
Quantitative assessment of the relationship between p21 Ser31Arg polymorphism and cervical cancer
Prognostic significance of several biomarkers in epithelial ovarian cancer: a meta-analysis of published studies
Association between p21 Ser31Arg polymorphism and cancer risk: a meta-analysis
P21 Ser31Arg polymorphism and cervical cancer risk: a meta-analysis
Meta-analysis of the relationship between p21 Ser31Arg polymorphism and lung cancer susceptibility
P21 codon 31 polymorphism associated with cancer among white people: evidence from a meta-analysis involving 78,074 subjects
The p21 Ser31Arg polymorphism and breast cancer risk: a meta-analysis involving 51,236 subjects
Polymorphisms in the BRCA1 and ABCB1 genes modulate menopausal hormone therapy associated breast cancer risk in postmenopausal women
Effects of a ciliary neurotrophic factor (CNTF) small-molecule peptide mimetic in an in vitro and in vivo model of CDKL5 deficiency disorder
Enhancement of Neurogenesis and Memory by a Neurotrophic Peptide in Mild to Moderate Traumatic Brain Injury
Neurotrophic peptides incorporating adamantane improve learning and memory, promote neurogenesis and synaptic plasticity in mice
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
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Quick Facts
- Class
- Neurotrophic Peptide
- Evidence
- Preliminary
- Safety
- Limited Data
- Updated
- Mar 2026
- Citations
- 33PubMed
Also known as
Tags
Related Goals
Evidence Score
Clinical Trials
View Clinical TrialsLinks to ClinicalTrials.gov for reference. Listing does not imply endorsement.
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