How P21 works
An experimental memory peptide with animal research and no established human dose or safety profile.
Also called: P021, P-21, Peptide 021, CNTF-derived P021.
Nootropic peptides · Adamantane-modified CNTF-derived peptide mimetic · Evidence: Animal studies only.
It copies a small part of CNTF, a signal that helps nerve cells survive. In lab studies it changes LIF signaling and can raise BDNF, another nerve-support signal. It is not the cell-cycle protein called p21. Effects in people are unknown.
- LIF/STAT3 signaling: Lab work suggests reduced LIF-driven STAT3 signaling; not a proven human drug target.
- BDNF and downstream TrkB/AKT/GSK3 pathways: BDNF and nerve-cell markers rose in some rodent models, but not in CDKL5-deficient mice.
Half-life: Unknown in humans. Plasma-stability claims do not establish how long a dose lasts in a person.
Related to P21
- Semax: A Russian nasal peptide with limited human evidence for brain and nerve effects.
- Selank: A Russian nasal anxiety peptide with uncertain long-term benefit and safety.
- PE-22-28: An experimental mood peptide studied in mice, with no human trials found.
- Dihexa: An experimental memory compound with disputed animal research and no established human dose.
- Cerebrolysin: An injectable pig brain mixture with mixed stroke, brain-injury and dementia evidence.
- BPC-157: An experimental repair peptide with mostly animal evidence and a few small human reports.
Sources
- 503B Bulk Drug Substances List, FDA · FDA · 2026
- Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act, FDA · FDA · 2026
- Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act, FDA · FDA · 2026
- Cellulitis, NHS · NHS · 2026
- Medicines, European Medicines Agency · European Medicines Agency · 2026
- MHRA Products | Home, MHRA · MHRA · 2026
- TGA strengthens compliance focus on unapproved peptide products as part of evolving risk response, Therapeutic Goods Administration · TGA · 2026
- The 2026 Prohibited List, World Anti-Doping Agency · WADA · 2026
- Think twice before injecting peptides bought online: unauthorized products can seriously harm you, Health Canada · Health Canada · 2026
- <797> FAQs, United States Pharmacopeia · 2023
- Anaphylaxis, NHS · NHS · 2023
- Drug Product Database: Access the database, Health Canada · Health Canada
- Drugs@FDA Data Files, FDA
- FYs 2013-2017 Regulatory Science Report: Complex Mixtures and Peptides, FDA · FDA
- P-21, FDA
Sources checked: 2026-10-18.
Information only, not medical advice. Peptifacts does not sell anything and does not link to sellers.