WhatPeptide

P21

P21 is a tetrapeptide derived from the ciliary neurotrophic factor (CNTF) binding interface, studied in animal models for neurogenesis stimulation, memory enhancement, and potential Alzheimer's disease prevention. It has shown the ability to increase BDNF levels and reduce tau hyperphosphorylation in rodent models.

Animal studies only Unregulated Nootropic

Written by WhatPeptide Editorial Team · Last updated 2026-03-17

Half-life

Unknown in humans; estimated short based on peptide size

Dosage range

Not established for humans; animal studies use nmol/kg range

Administration

Subcutaneous injection

Research level

Animal only

How P21 works

P21 (P021, Ac-DGGLAG-NH2) inhibits leukemia inhibitory factor (LIF) signaling via the JAK/STAT3 pathway, removing inhibitory constraints on BDNF expression and neurogenic programs. This promotes adult hippocampal neurogenesis and synaptic plasticity.

Also known as: CNTF peptide, P021, Cognitive enhancer peptide

Research relevance

Cognition & Focus
Strong research relevance 80

Side effects & safety

No human safety data available Potential immune activation Unknown long-term effects

Contraindications

No established human safety profile
Pregnancy
Active neurological conditions without supervision

Consult a healthcare provider before use if any of these apply to you.

Key studies

FAQ

What is P21? +
P21 is a tetrapeptide derived from the ciliary neurotrophic factor (CNTF) binding interface, studied in animal models for neurogenesis stimulation, memory enhancement, and potential Alzheimer's disease prevention. It has shown the ability to increase BDNF levels and reduce tau hyperphosphorylation in rodent models. Its mechanism of action is based primarily on animal and in-vitro studies.
What is P21 researched for? +
P21 has the strongest research relevance for Cognition & Focus. Evidence is based primarily on animal and in-vitro studies.
What are the side effects of P21? +
Reported side effects include No human safety data available, Potential immune activation, Unknown long-term effects. Key contraindications: No established human safety profile; Pregnancy; Active neurological conditions without supervision.
Is P21 FDA approved? +
P21 is not FDA-approved. It is available as a research compound or through compounding pharmacies in some jurisdictions.
How is P21 administered? +
P21 is typically administered via subcutaneous route. Researched dosage range: Not established for humans; animal studies use nmol/kg range. Half-life: Unknown in humans; estimated short based on peptide size.

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