P21
Aliases: P021 · CNTF-derived peptide
Last verified: 2026-09-23
The short version
A tetrapeptide derived from CNTF (ciliary neurotrophic factor) — designed to enhance hippocampal neurogenesis. A potential nootropic/neurorestorative peptide. Key fact: No controlled human trials exist. Everything known about P21 in humans comes from indirect sources and self-reports. Status: preclinical. Not approved; research only.
Identity & type
- Molecular type
- analog
- Origin
- A tetrapeptide derived from CNTF (ciliary neurotrophic factor) — designed to enhance hippocampal neurogenesis.
Mechanism of action
Increases BDNF, inhibits GSK-3β and reduces tau hyperphosphorylation; stimulates dentate-gyrus neurogenesis.
not confirmed in humans
Dosing & routes
Official / clinical context
No approved official document exists for P21. Any protocols mentioned are to be read as information, not as a recommendation.
Regulator-approved labeling and published study designs — never a recommendation.
Community-reported practice
Preclinical only (mice, nasal/SC); no human doses exist. The nootropic community reports subtle memory and cognitive-endurance improvements over weeks; effects are soft and hard to separate from placebo.
Unverified self-reports. Not medical advice. Not endorsement.
Expected effects (community)
The nootropic community reports subtle memory and cognitive-endurance improvements over weeks; effects are soft and hard to separate from placebo.
Protocol — official vs community
Official / label
No approved protocol exists — preclinical agent. P21 (P021) has only mouse Alzheimer's-model data; no human dose of any kind has been established.
Duration: —
Nasal and injectable routes appear in the animal literature, which some vendors cite as if they translated to humans. They do not.
Community (anecdotal)
Structured protocol data for this entry is coming.
Human evidence
No controlled human trials exist. Everything known about P21 in humans comes from indirect sources and self-reports.
Preclinical evidence
Mouse Alzheimer's-model studies: improved memory, reduced amyloid/tau pathology.
Known risks
- Unknown in humans.characterized
- Unregulated injectable supply — sterility, purity and accurate dose not assuredtheoretical
Teal: characterized in clinical/labeling contexts. Amber: theoretical or reported outside controlled settings.
Unknowns & evidence gaps
- All human pharmacokinetics, safety and efficacy
Frequently asked questions
References
Systematic references are being expanded; verify sources directly before any decision.