Peptide library / Brain & sleep / P21
P21
A small peptide based on ciliary neurotrophic factor, studied in mice for memory and neurogenesis.
Effects studied or claimed
What it is used or promoted for, and where each effect has actually been seen
- Memory in Alzheimer mouse modelsAnimals
- NeurogenesisAnimals
How it is thought to work
P21 mimics the active part of CNTF and appears to increase production of new nerve cells and BDNF in the hippocampus.
What the evidence shows
Mouse studies showed improved memory and reduced tau pathology. No human trials have been completed.
Safety and unknowns
Human safety is unknown.
Regulatory status
Not approved. Preclinical research only.
Regulatory status changes quickly. This entry was last reviewed on 27 October 2026. Confirm current status with the FDA before relying on it.
More in Brain & sleep
PE-22-28
Wellness and performanceA short synthetic peptide studied in mice as a fast-acting antidepressant.
Pinealon
Wellness and performanceA three amino acid peptide from the Khavinson group, studied for brain protection.
Noopept
Wellness and performanceA dipeptide-like compound developed in Russia and sold as a memory aid.
General information, not medical advice. Do not buy or inject unregulated peptides.