Is P021 approved or available as a medicine?

No. It has no regulatory approval anywhere and exists only as an investigational research compound.

Has P021 been tested in humans?

No published human trials exist. All data are from cell and rodent Alzheimer's and aging models.

What conditions has it been studied for preclinically?

Rodent studies address Alzheimer's disease, cognitive aging, Down syndrome models, and related neurodevelopmental conditions.

Are there known human side effects?

The human safety and interaction profile is unknown because no human studies have been performed.

Research chemical — not approvedaka Cntf-derived peptide 021, P021

P21 — Complete Research Guide (2026)

Last updated 2026-06-25

TL;DR

A ciliary-neurotrophic-factor-derived peptidomimetic studied in preclinical neurodegeneration models; not approved for human use.

What is P21?

P21 (also written P021 or P-021) is a small, blood-brain-barrier-permeable peptidomimetic derived from a biologically active region of ciliary neurotrophic factor (CNTF), developed by the Iqbal group; it is distinct from the cell-cycle protein p21.

It is an investigational research compound with no FDA, EMA, or other regulatory approval, and it is not a medicine or supplement.

The evidence base is entirely preclinical, consisting of cell and rodent studies in Alzheimer's-disease and aging models; no human trials have been published.

How does P21 work?

P021 is designed to mimic a neurotrophic CNTF domain and is reported to enhance neurogenesis and BDNF signaling while inhibiting leukemia inhibitory factor signaling, effects studied preclinically for synaptic and cognitive outcomes. [INFOGRAPHIC: P021 CNTF-mimetic neurotrophic signalling]

What does the research say about P21?

In a transgenic Alzheimer mouse model, chronic oral P021 was disease-modifying, reducing tau pathology and improving cognition (preclinical only). ^[1]
In aged rodents, P021 rescued cognitive decline by promoting neurogenesis and synaptic plasticity (preclinical only). ^[2]
Early P021 treatment prevented amyloid-beta and tau pathologies, neurodegeneration, and cognitive deficits in AD-model mice (preclinical only). ^[5]

Clinical research & studies

The references below are the primary sources cited throughout this guide. Each links directly to PubMed or the regulator. Where evidence is preclinical (animal or in-vitro), that is stated rather than implied.

[1] Disease modifying effect of chronic oral treatment with a neurotrophic peptidergic compound in a triple transgenic mouse model of Alzheimer's disease — Kazim SF et al., Neurobiol Dis 2014. (animal)
[2] Rescue of cognitive-aging by administration of a neurogenic and/or neurotrophic compound — Bolognin S et al., Neurobiol Aging 2014. (animal)
[3] Neurotrophic factor small-molecule mimetics mediated neuroregeneration and synaptic repair — Kazim SF et al., Mol Neurodegener 2016. (animal)
[4] Prevention of dendritic and synaptic deficits and cognitive impairment with a neurotrophic compound — Baazaoui N et al., Alzheimers Res Ther 2017. (animal)
[5] Prevention of Amyloid-beta and Tau Pathologies, Associated Neurodegeneration, and Cognitive Deficit by Early Treatment with a Neurotrophic Compound — Baazaoui N et al., J Alzheimers Dis 2017. (animal)
[6] Alzheimer's Disease: Challenges and a Therapeutic Opportunity to Treat It with a Neurotrophic Compound — Baazaoui N et al., Biomolecules 2022. (review)

Dosing context

This is not medical advice or a usage recommendation. Dosing figures are reported research context only, cited from the published literature.

No human dosing has been established; published regimens exist only as animal doses within controlled experimental protocols and should not be extrapolated to people.

This entry describes research context only and is not a protocol or recommendation for human administration.

Side effects & safety profile

There are no human safety data for P021; all tolerability and toxicity information derives from rodent studies.

Published rodent work reports favorable tolerability and oral bioavailability, but long-term safety, drug interactions, and human adverse-effect profiles are entirely uncharacterized.

Because it modulates neurotrophic signaling pathways, off-target neurological or proliferative effects in humans cannot be excluded and have not been studied.

Stacking & combinations

No combination regimens have been studied in humans; any stacking with other compounds is unstudied and outside the published evidence.

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Frequently asked questions

No. This P021 is a CNTF-derived neurotrophic peptidomimetic and is unrelated to the cell-cycle protein p21 (CDKN1A).

References

[1] Disease modifying effect of chronic oral treatment with a neurotrophic peptidergic compound in a triple transgenic mouse model of Alzheimer's disease — Kazim SF et al., Neurobiol Dis 2014. PMID: 25046994. View sourceStudy: animalChronic oral P021 reduced tau pathology and produced disease-modifying cognitive benefit in 3xTg-AD mice.
[2] Rescue of cognitive-aging by administration of a neurogenic and/or neurotrophic compound — Bolognin S et al., Neurobiol Aging 2014. PMID: 24702821. View sourceStudy: animalP021 improved age-related cognitive decline via enhanced neurogenesis and synaptic plasticity in rodents.
[3] Neurotrophic factor small-molecule mimetics mediated neuroregeneration and synaptic repair — Kazim SF et al., Mol Neurodegener 2016. PMID: 27400746. View sourceStudy: animalThe CNTF-derived mimetic P021 promoted neuroregeneration and synaptic repair in AD-model mice.
[4] Prevention of dendritic and synaptic deficits and cognitive impairment with a neurotrophic compound — Baazaoui N et al., Alzheimers Res Ther 2017. PMID: 28655344. View sourceStudy: animalP021 prevented dendritic/synaptic loss and cognitive impairment in an AD mouse model.
[5] Prevention of Amyloid-beta and Tau Pathologies, Associated Neurodegeneration, and Cognitive Deficit by Early Treatment with a Neurotrophic Compound — Baazaoui N et al., J Alzheimers Dis 2017. PMID: 28387677. View sourceStudy: animalEarly P021 treatment prevented amyloid-beta and tau pathology and cognitive deficits in AD-model mice.
[6] Alzheimer's Disease: Challenges and a Therapeutic Opportunity to Treat It with a Neurotrophic Compound — Baazaoui N et al., Biomolecules 2022. PMID: 36291618. View sourceStudy: reviewReviews the preclinical rationale and evidence for the neurotrophic compound P021 in Alzheimer's disease.

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This article is for educational and research purposes only. Peptides discussed here are not approved for human consumption by the FDA, EMA, or equivalent regulators outside of specific clinical contexts. Always consult a licensed medical professional before any therapeutic use.