P21
Also known as: P021
Molecular Identifiers
Molecular Formula
C27H42N6O8
CAS Number
1246751-68-7
PubChem CID
56599151UNII
VV8CZC8PAS
Molecular Weight
578.7 Da
Overview
Peptide derived from CNTF (ciliary neurotrophic factor). Promotes BDNF upregulation and hippocampal neurogenesis. Inhibits tau protein phosphorylation, being researched in Alzheimer's and cognitive decline models.
The main interest in P21 is the combination of BDNF upregulation, hippocampal neurogenesis promotion, and inhibition of tau protein phosphorylation — three central targets in research on Alzheimer's, age-related cognitive decline, and synaptic plasticity. Reducing tau hyperphosphorylation is a relevant differentiator compared with other peptide nootropics.
It has no regulatory approval from any agency (FDA, EMA, ANVISA). P21 remains in advanced preclinical research and its human use occurs outside the approved clinical context, restricted to the research market. Typical protocols are 4-12 week cycles with daily subcutaneous administration. Evidence is still mostly animal, with cautious extrapolation to humans.
Among peptide nootropics, P21 (a CNTF derivative) is unique in combining BDNF upregulation with anti-tau activity, a pair of targets not covered by the Russian peptides Selank (GABAergic anxiolytic) or Semax (focus/attention via BDNF), nor by Cerebrolysin (a broad neurotrophic hydrolysate). It shares with Dihexa (HGF/c-Met) the Alzheimer focus, but through a distinct mechanism; compared with PE 22-28 (TREK-1, depression), it occupies a cognitive rather than affective niche. Evidence remains mostly preclinical.
Modified peptide — derived from CNTF with prenylated group, non-conventional sequence
Half-life
~4-8 hours
Administration Route
Subcutaneous
Category
Cognitive & Neuroprotective
Mechanism of Action
- BDNF upregulation (brain-derived neurotrophic factor)
- Promotion of hippocampal neurogenesis
- Inhibition of tau protein phosphorylation
- Improvement of synaptic plasticity and memory
- Neuroprotective action against neurodegeneration
Reported Side Effects
Adverse effects described in the literature. Severity and frequency vary between individuals.
- Mild headache
- Injection site pain
Product Properties
| Purity | >98% |
| Appearance | White lyophilized powder |
| Solubility | Soluble in water and bacteriostatic water |
| Source | Solid-phase peptide synthesis (SPPS) |
| Storage | Lyophilized: -20°C for up to 2 years, 2-8°C for up to 6 months. Reconstituted: 2-8°C for up to 4 weeks. Protect from light and moisture. Avoid repeated freeze-thaw cycles. |
Presentations & Preparation
Vials of P21 found in the research market:
Reconstitution
- Diluent: Bacteriostatic water
- Volume: 2 ml per vial
- Inject the diluent slowly against the vial wall
- Gently swirl until fully dissolved
- Never shake
Storage
- Lyophilized: Refrigerated 2-8°C
- Reconstituted: Refrigerated 2-8°C (up to 30 days)
- Protect from direct light
- Do not freeze after reconstitution
Scientific Studies
Published studies on P21.
Disease Modifying Effect of Chronic Oral Treatment with a Neurotrophic Peptidergic Compound in a Triple Transgenic Mouse Model of Alzheimer's Disease
Kazim SF, Blanchard J, Dai CL, Tung YC, LaFerla FM, Iqbal IG, Iqbal K
Neurotrophic Peptides Incorporating Adamantane Improve Learning and Memory, Promote Neurogenesis and Synaptic Plasticity in Mice
Li B, Wanka L, Blanchard J, Liu F, Chohan MO, Iqbal K, Grundke-Iqbal I
Related Peptides
Adamax
100-500 mcg via intranasal or subcutaneous · 1-2 times daily
Cerebrolysin
5-30 ml per injection · Once daily
Cortagen
Dihexa
DSIP
100-300 mcg per subcutaneous injection · Once daily
Epithalon
1-5 mg per subcutaneous injection (some protocols use 5-10 mg per full cycle) · Once daily or every other day