Cognitive ⏱ Half-life: Not well characterized. Intranasal route preferred for CNS delivery. Preclinical

P21

P21 (CNTF-derived Peptide)

Updated March 15, 2026

Evidence at a Glance

Regulatory statusPreclinical
CNTF-derived neurotrophic peptide (Ac-DGGLAG-NH2 / P021); animal-only, no registered or published human trials
Human evidenceNone
Animal evidenceModerate

A CNTF-derived neurotrophic peptide that improves cognition, neurogenesis and tau pathology in rodent models of Alzheimer's and Down syndrome; it has been proposed for clinical development but has no registered or published human trials.

What the research does not support

  • No human data of any kind exist, including pharmacokinetics, safety or efficacy.
  • It is not shown to treat or prevent Alzheimer's disease in people.
  • It is not FDA-approved and remains preclinical.
Half-Life
Not well characterized. Intranasal route preferred for CNS delivery.
Mol. Weight
~580 g/mol

What is P21?

P21 is a neurogenic peptide derived from CNTF that has generated significant interest in neurodegenerative disease research. Its ability to promote new neuron formation in the adult hippocampus makes it relevant to both cognitive enhancement and disease modification research.

Research Applications

Hippocampal neurogenesis, Alzheimer’s disease models, cognitive enhancement, BDNF pathway research, and neural stem cell biology.

Dosage Information (Research Use)

Animal research: 60-750 nmol/g intranasally or peripherally. Research use only.

Reconstitution & Handling

Standard BAC water reconstitution.

Half-Life & Pharmacokinetics

Not well characterized. Intranasal route preferred for CNS delivery.

Reported Observations in Literature

Limited data. Generally well-tolerated in animal models.

Key Research References

  • Bolognin D, et al. “An experimental rat model of sporadic Alzheimer’s disease and rescue of cognitive impairment with a neurotrophic peptide.” Acta Neuropathol. 2012

How P21 Works

P21 is a small peptide derived from ciliary neurotrophic factor (CNTF) that promotes neurogenesis and dendritic branching in the hippocampus. It works by inhibiting leukemia inhibitory factor (LIF) signaling and increasing BDNF levels, promoting the proliferation and differentiation of neural progenitor cells.

Research Findings

Published data in Alzheimer's disease mouse models shows improved spatial memory and increased hippocampal neurogenesis. One of few compounds shown to rescue cognitive deficits in established neurodegeneration models.

Dosage & Administration

Animal research: 60-750 nmol/g intranasally or peripherally. Research use only.

Safety & Side Effects

Limited data. Generally well-tolerated in animal models.

Important: All safety information is derived from published research, primarily animal studies. No controlled human clinical trial data exists unless explicitly noted. This compound is sold for research purposes only.

Quick Facts

Sequence Ac-DGGL-NH2 (modified)
Molecular Weight ~580 g/mol
Half-Life Not well characterized. Intranasal route preferred for CNS delivery.
Available Sizes 5mg
Storage Lyophilized: -20°C. Reconstituted: 2-8°C.

Key Research References

  • Bolognin D, et al. "An experimental rat model of sporadic Alzheimer's disease and rescue of cognitive impairment with a neurotrophic peptide." Acta Neuropathol. 2012

Related Peptides

View all →
Cerebrolysin
Cognitive
Porcine brain-derived peptide mixture approved in 50+ countries for stroke recovery and dementia, with neurotrophic factor-like activity.
View Profile →
N-Acetyl Selank
Cognitive
Enhanced-stability version of Selank with improved bioavailability and prolonged anxiolytic/nootropic effects.
View Profile →
Dihexa
Cognitive
Angiotensin IV analog reported to be 10 million times more potent than BDNF for synaptogenesis in animal models.
View Profile → Buy Now