Neuro/Cognitive Peptides
P21 (P021)
Commonly used for
Cognitive FunctionMemory SupportHealthy Aging
What is it?
P21 (P021) is a small-molecule neurotrophic peptide mimetic derived from ciliary neurotrophic factor (CNTF) signaling pathways that supports brain-derived neurotrophic factor (BDNF) pathways and neuronal health.
Mechanism of action: Modulates BDNF/neurotrophic signaling (reported in animal studies); Supports hippocampal neurogenesis and synaptic plasticity (reported in animal studies)
What do people use it for?
Proposed indications: Neuroprotection (animal studies); Cognitive function (animal studies); Memory (animal studies)
How is it used? / Dosing
Typical clinical dosing schedule: No established clinical dosing. Human use has been limited to early-phase, primarily preclinical research.
Administration: Research injection (subcutaneous); intranasal explored in preclinical research — No established clinical dosing
How does it compare?
Compare with:
How well does it work? / Evidence
? Emerging / limited evidence
An "emerging / limited evidence" rating means rigorous research hasn't caught up yet -- not that this peptide doesn't work. Many peptides in this category are newer or simply understudied rather than proven ineffective.
Evidence rating: ⭐⭐☆☆☆ — Animal studies of the published CNTF-derived compound (P021) report effects on BDNF expression, hippocampal neurogenesis, synaptic plasticity, and cognition; human clinical trial data are lacking. Displayed as "P21 (P021)" since that shorthand is sometimes used ambiguously for other compounds.
Safety & side effects
Common side effects: Human safety profile remains incompletely characterized.
Serious risks: Unknown long-term safety; most available data is preclinical/animal-based.
Legal & regulatory status
Legal status: Not FDA-approved for human use. This is a research compound, not a medication — any use should only occur under the direction of a licensed healthcare provider, and its legal availability varies and changes frequently. Verify current status independently before considering use.
Regulatory status: Research peptide • Not FDA approved
Who should avoid it?
Contraindications: Not established. Avoid in:; Pregnancy; Active malignancy; Uncontrolled illness outside research settings
Pregnancy & breastfeeding: Avoid.
Research & references
Li B, Wanka L, Blanchard J, et al. (2010). Neurotrophic peptides incorporating adamantane improve learning and memory, promote neurogenesis and synaptic plasticity in mice. FEBS Letters. Kazim SF, Iqbal K. (2016). Neurotrophic factor small-molecule mimetics mediated neuroregeneration and synaptic repair: emerging therapeutic modality for Alzheimer's disease. Molecular Neurodegeneration, 11.