P21
Research OnlyAlso known as: Ac-DGGLAG-NH2, P021, CNTF-derived peptide
A hexapeptide (Ac-DGGLAG-NH2) derived from ciliary neurotrophic factor (CNTF) that is claimed to mimic BDNF effects and promote neurogenesis. Developed primarily at the New York State Institute for Basic Research. Limited to preclinical rodent studies with no human clinical trials. Sold as a research chemical with unknown safety profile.
Research Statistics
Synthetic CNTF fragment with exclusively preclinical neurogenesis data; CNTF receptor signaling is proposed but no human studies exist for this specific peptide modification.
Research Dossier
Overview
What is P21 and what does the research say?
Mechanism of Action
The proposed mechanisms of P21 are based entirely on animal and in vitro studies. No human mechanistic data exists.
How It Works (Simplified)
P21 is designed to bypass the blood-brain barrier and activate neurotrophic signaling:
Increases brain-derived neurotrophic factor expression by inhibiting leukemia inhibitory factor (LIF) signaling pathway.
Promotes formation of new neurons in dentate gyrus through enhanced proliferation and maturation of neural progenitor cells.
Via BDNF/TrkB/PI3K/Akt pathway, inhibits GSK-3beta activity - reducing abnormal tau hyperphosphorylation.
Restores synaptic proteins (PSD-95, synapsin-1) and glutamate receptors supporting plasticity and memory.
Scientific Pathways
BDNF/TrkB/GSK-3beta Pathway (Tau Modulation)
P21 → LIF signaling inhibition → BDNF upregulation → TrkB activation
↓
PI3K → Akt → GSK-3beta inhibition
↓
Reduced tau hyperphosphorylationNeurogenesis Pathway (Hippocampal)
P21 → BDNF increase → TrkB/CREB activation → Neural progenitor proliferation
↓
DCX+ immature neurons → Mature neuronsKey Research: Li B et al. (2010) demonstrated neurogenesis enhancement in normal mice. PMID:20600002
Important Limitations
- All studies from a single research group (Iqbal laboratory at IBR)
- No independent replication of key findings
- Translation to human physiology is completely unknown
- No human pharmacokinetics or safety data
- 15+ years of research with no clinical trial advancement
- “BDNF-mimetic” claim not fully validated at receptor level
Evidence-Chained Benefits
Evidence-Chained Benefits
Research findings linked to mechanisms and clinical outcomes
What to Expect
Timeline based on observations from published studies. Individual responses may vary.
Based on preclinical observations: Initial BDNF pathway activation may begin. Animal studies show early changes in CREB phosphorylation and neurotrophin signaling within days. No human timeline data available.
Animal studies suggest neural progenitor proliferation increases. In mouse models, Ki-67+ cells (proliferating) and DCX+ cells (immature neurons) show measurable increases by 2-4 weeks of treatment.
Preclinical models show continued neurogenesis and early synaptic protein restoration. Tau phosphorylation changes and GSK-3beta inhibition effects observed in AD mouse models within this timeframe.
Long-term animal studies (3-12 months) suggest sustained cognitive improvements and ongoing neuroprotection. However, human pharmacokinetics, optimal dosing, and treatment duration are completely unknown.
Research-Based Observations
This timeline reflects observations from published clinical and preclinical studies. Individual responses may vary significantly. This is not a guarantee of effects or a dosing schedule. Consult qualified healthcare providers for personalized guidance.
Quality Checklist
Visual indicators to help evaluate P21 product quality
Good Signs (7 indicators)
Warning Signs (6 indicators)
Bad Signs (7 indicators)
For Research Evaluation Only
These quality indicators are general guidelines based on typical peptide characteristics. Professional laboratory testing (HPLC, mass spectrometry) provides definitive quality verification. This checklist is for initial visual evaluation only.
Peptide Interactions
Known and theoretical interactions when combining P21 with other peptides. Based on published research and mechanistic considerations.
Dihexa
CompatibleBoth target cognitive enhancement through different mechanisms. P21 focuses on BDNF/neurogenesis while Dihexa acts on HGF/c-Met pathway. No interaction studies available; theoretical complementary nootropic effects.
Semax
CompatibleDifferent neurotrophic mechanisms. P21 is CNTF-derived targeting BDNF while Semax is ACTH-derived with broader neuroprotective effects. No known contraindications; both aim to support cognitive function.
Cerebrolysin
CompatibleCerebrolysin is a complex peptide mixture with neurotrophic properties. P21 has a more targeted mechanism via BDNF pathway. No interaction data available; both target neuroregeneration.
Selank
CompatibleNon-overlapping mechanisms. P21 targets neurogenesis while Selank modulates anxiety and immune function. Theoretical complementary cognitive benefits.
BPC-157
CautionBoth have neuroprotective claims but through different pathways. BPC-157 affects dopaminergic system while P21 targets BDNF/LIF signaling. Limited data on CNS interactions; exercise caution.
Research Note: Interaction data is based on published literature, mechanistic understanding, and theoretical considerations. Most peptide combinations lack direct clinical study. This information is for educational purposes only and does not constitute medical advice. Always consult qualified healthcare providers.
References
Key Studies Cited
Full reference list available on request. All citations link to PubMed for verification.
Methodology Note
This dossier synthesizes available evidence from peer-reviewed literature, regulatory documents, and clinical trial registries. Evidence strength ratings follow a modified GRADE approach.
For complete methodology details, see our Methodology page.
Important Disclaimer
This dossier is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before making health decisions.
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