About P21
Derived from CNTF; increases BDNF expression and promotes hippocampal neurogenesis; modulates PI3K/Akt pathway
P021 (also designated Peptide 6) is a synthetic tetrapeptide derived from the neurotrophic activity domain of ciliary neurotrophic factor (CNTF), developed to provide the neuroprotective and neurogenic actions of endogenous CNTF at small-molecule scale, with adamantane incorporation designed to improve oral bioavailability and CNS penetrance. It is proposed to upregulate BDNF and other neurotrophic factors through MAPK/ERK signaling pathways, promoting hippocampal neurogenesis, supporting synaptic plasticity, and reducing tau hyperphosphorylation in preclinical models of neurodegeneration. Rodent studies from the Iqbal laboratory at the NYS Institute for Basic Research have demonstrated that P021 improves learning and memory, promotes hippocampal neurogenesis, and reduces amyloid-β and tau pathological markers in transgenic mouse models of Alzheimer's disease. P021 is a research compound with no regulatory approval in any jurisdiction; all published evidence to date is from preclinical animal studies, and no human clinical trials have been registered or completed as of 2025. P21 as a CNTF-pathway peptide In the nootropic and cognitive peptide research context, P21 refers to a synthetic peptide analogue based on the ciliary neurotrophic factor (CNTF) receptor-binding domain, designed to activate CNTF signalling without the full-length protein's size limitations and potential inflammatory side effects associated with systemic CNTF administration. CNTF is a neuroprotective cytokine that promotes neuron survival, enhances BDNF production, and supports hippocampal plasticity — pathways relevant to learning, memory consolidation, and neuronal resilience. Research on P21 in rodent models has reported improved spatial learning and memory retention, reduced tau phosphorylation markers associated with neurodegeneration, and effects on hippocampal synaptic density. Clinical data is absent; all published evidence comes from preclinical animal studies. P21 is available as a research peptide from specialty vendors; it is not approved by any regulatory agency and has no established safety or dosing profile in humans. It is discussed within nootropic communities alongside semax, selank, and dihexa as a peptide with proposed neuroprotective and cognitive-enhancement mechanisms, though its evidence base is substantially thinner than those compounds.
P21 Benefits & Research Areas
Research Signals
Population research notes
These signals reflect research interest areas, not treatment indications.
Regulatory & Evidence
Risk Profile
Generally considered lower risk in research contexts. Risk profile varies by individual — review contraindications before use.
Regulatory Status
- Availability Status
- Research Only
- FDA Status
- Not Evaluated
CNTF-derived pentapeptide fragment studied for cognitive enhancement in animal models. No FDA approval, no NDA or IND. Not on any FDA list. Very limited human research. Research compound.
Regulatory status reflects publicly available information and may change. This is not legal or medical advice.
Research Sources
7 sources cited · 7 moderate
5 Cohorts · 2 Animals
β-Ecdysterone Attenuates Ang II-Induced Senescence in Human Aortic Smooth Muscle Cells via Autophagy Activation and ROS Suppression Through AKT/mTOR Pathway Inhibition.
Front Biosci (Landmark Ed) · 2026
# Summary Research found that β-ecdysterone attenuates premature senescence in human aortic smooth muscle cells induced by angiotensin II through activation of autophagy and suppression of reactive oxygen species via inhibition of the AKT/mTOR signaling pathway. This study demonstrated that β-ecdysterone treatment reduced senescence markers including p53 and p21 expression, restored normal cell cycle progression, and decreased inflammatory mediator secretion in the affected cells.
δ-Tocotrienol re-sensitizes vemurafenib-resistant melanoma cells to BRAF inhibition via modulation of AKT signaling.
Food Res Int · 2026
# Summary Research found that δ-tocotrienol re-sensitized vemurafenib-resistant melanoma cells to BRAF inhibition by suppressing AKT signaling, inducing cell cycle arrest through p21 upregulation, and triggering apoptosis. This study demonstrated a synergistic interaction between δ-tocotrienol and vemurafenib in resistant melanoma models, suggesting potential therapeutic value for combination approaches to overcome drug resistance.
PRMT6 inhibition or deficiency attenuates diabetic neuropathic pain in male mice and is associated with reduced spinal neuroinflammation, microgliosis, and altered p53-p21 signaling.
J Neuroinflammation · 2026
# Summary Research found that PRMT6, an enzyme upregulated in spinal microglia during diabetes, promotes pain hypersensitivity in male mice by methylating the p53 protein and suppressing p21 expression, thereby increasing microglial proliferation and neuroinflammation. This study demonstrated that blocking or deleting PRMT6 attenuated diabetic neuropathic pain and reduced microglial activation through restoration of the p53-p21 signaling pathway, suggesting PRMT6 as a potential therapeutic target for this condition in males.
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ACOD1 deficiency promotes DDX1 methylation-mediated mitochondrial dysfunction and dermal papilla cell senescence in androgenetic alopecia.
BMC Med · 2026
# Summary Research found that ACOD1 deficiency promotes dermal papilla cell senescence in androgenetic alopecia by increasing DDX1 methylation, which leads to mitochondrial dysfunction characterized by reduced energy production and increased oxidative stress. This study demonstrated that restoring ACOD1 function or supplementing with its metabolic product improved mitochondrial health and reduced senescence markers associated with hair loss.
Regulation of Lens Epithelial Cell Senescence by Cyclic Mechanical Stretch: Multi-Omics Insights into the Mechanisms of Lens Aging.
Exp Eye Res · 2026
I appreciate your request, but I'm unable to provide a summary of the primary findings regarding P21 from this research. While you've provided the title and author information, the actual abstract content—which would contain the study's findings and results—has not been included in your submission. To accurately summarize the research findings using appropriate educational framing, I would need the full abstract text that describes the study's methodology, results, and conclusions about P21's role in lens epithelial cell senescence. Could you please provide the complete abstract?
Prevention of Amyloid-β and Tau Pathologies, Associated Neurodegeneration, and Cognitive Deficit by Early Treatment with a Neurotrophic Compound
Journal of Alzheimer's Disease · 2017
Research in 3xTg-AD transgenic mice found that early continuous treatment with the neurotrophic compound P021 (related to P21) initiated before overt pathology prevented neurodegeneration, reduced amyloid-β and tau accumulation, rescued episodic memory impairment, and markedly reduced mortality over 18 months of follow-up, establishing early neurotrophic intervention as a secondary prevention strategy.
Neurotrophic peptides incorporating adamantane improve learning and memory, promote neurogenesis and synaptic plasticity in mice
FEBS Letters · 2010
Research in adult C57Bl6 mice found that peripheral administration of the neurotrophic peptide P21 (Ac-DGGLAG-NH2) enhanced short-term memory and spatial reference memory compared with vehicle controls and promoted neurogenesis and maturation of newly born neurons in the dentate gyrus, demonstrating that small neurotrophic peptides can improve cognitive function in normal adult animals.
P21 Side Effects & Safety Considerations
Generally considered lower risk in research contexts. Individual response varies — review all considerations before use.
Reported contraindications & considerations
Consult a qualified healthcare professional before making any health decisions. This information is educational only and does not constitute medical advice.
Where to Buy P21 — Providers & Availability
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Questions to Ask Your Provider
Frequently Asked Questions — P21
P021 (also designated Peptide 6) is a synthetic tetrapeptide derived from the neurotrophic activity domain of ciliary neurotrophic factor (CNTF), developed to provide the neuroprotective and neurogenic actions of endogenous CNTF at small-molecule scale, with adamantane incorporation designed to improve oral bioavailability and CNS penetrance. It is proposed to upregulate BDNF and other neurotrophic factors through MAPK/ERK signaling pathways, promoting hippocampal neurogenesis, supporting synaptic plasticity, and reducing tau hyperphosphorylation in preclinical models of neurodegeneration.
neurogenesis, BDNF upregulation, memory enhancement, neuroprotection.
Research on P21 primarily documents effects related to neurogenesis and BDNF upregulation and memory enhancement and neuroprotection. These are areas covered in preclinical and clinical literature — individual response varies and effects depend on context of use.
Reported contraindications and considerations for P21 include none well-established. This is educational information only — consult a qualified healthcare professional before use.
4 providers in the directory currently offer P21.
# Summary Research found that β-ecdysterone attenuates premature senescence in human aortic smooth muscle cells induced by angiotensin II through activation of autophagy and suppression of reactive oxygen species via inhibition of the AKT/mTOR signaling pathway. This study demonstrated that β-ecdysterone treatment reduced senescence markers including p53 and p21 expression, restored normal cell cycle progression, and decreased inflammatory mediator secretion in the affected cells.