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For research and educational purposes only. Not intended for human consumption.

P21

Limited Research
Updated Dec 2025

CNTF-Derived Tetrapeptide | Neurogenesis & Cognitive Enhancement

InjectableNasal
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50-100mcg
Once daily
Injectable
Subcutaneous: abdominal fat
4-12 weeks
Typical duration
2-8°C
Refrigerated

Overview

What is P21?

P21 (also known as P021) is a synthetic tetrapeptide derived from the biologically active region of human ciliary neurotrophic factor (CNTF). Featuring an adamantylated glycine at its C-terminus for enhanced stability, P21 promotes neurogenesis, enhances synaptic plasticity, and has shown promise in Alzheimer's disease models by reducing tau pathology and improving cognitive function.

Key Benefits

Promotes adult hippocampal neurogenesis, enhances synaptic plasticity via BDNF increase, reduces tau hyperphosphorylation, improves learning and memory in AD models, orally bioavailable and BBB-penetrant.

Mechanism of Action

P21 competitively inhibits leukemia inhibitory factor (LIF) signaling, disinhibiting neurogenesis in the adult hippocampus. This triggers BDNF expression, dendritic arborization, and synaptogenesis while reducing GSK-3β activity to decrease tau pathology.

Molecular Information

546.64 Da
Weight
4
amino acids
Adamantylated tetrapeptide
Type
Amino Acid Sequence:
Ac-Asp-Gly-Gly-Leu-Adamantylamide (Ac-DGGL-NH2)
* C-terminal adamantyl group provides metabolic stability and enhances BBB penetration

Pharmacokinetics

Peak
1 hr
Half-life
3 hrs
Cleared
~15 hrs
100%50%0%0h6h12h18h24h
Peak
Half-life
Cleared
Bhattarai et al. 2020

Research Indications

Memory Enhancement

Improves spatial and recognition memory in aged and AD model mice through hippocampal neurogenesis.

Learning Acceleration

Enhances acquisition and retention of new information via synaptic plasticity mechanisms.

Alzheimer's Disease Research

Reduces tau pathology, increases BDNF, and improves cognition in transgenic AD models.

Research Protocols

Disclaimer: P21 is a research compound with no human clinical trials. All dosing is extrapolated from animal studies. Consult a healthcare provider before use.

GoalDoseFrequencyRoute
Preclinical Research (Mouse)10 nmol/gDaily in dietOral
Cognitive Enhancement (Research)50-100mcgOnce dailySubcutaneous
Conservative Start25-50mcgOnce dailySubcutaneous
Intranasal (Research)100-200mcgOnce dailyIntranasal

Timing: Morning administration may align better with natural neuroplasticity rhythms. Consistent daily dosing is important for neurogenic effects.

Peptide Interactions

How to Reconstitute

Important: Always use bacteriostatic water (BAC). Sterile technique is essential.

1

Allow vial to reach room temperature

2

Add bacteriostatic water slowly down vial side

3

Gently swirl to dissolve - do not shake

4

Solution should be clear and colorless

5

Label with concentration and date

6

Store refrigerated at 2-8°C

7

Use within 4 weeks of reconstitution

Dosing Calculator

Calculate your injection volume with visual dosing guide

FINAL CONCENTRATION
2.50mg/mL
Each milliliter contains 2.50 mg of peptide
VISUAL REFERENCE (RESEARCH USE ONLY)

To obtain 250 mcg from this solution:

Draw 0.10 mL=10 units

(1 mL = 100 units on any insulin syringe)

0102030405060708090100
00.10.20.30.40.50.60.70.80.91.0
0.10 mL
10 units

Draw to this mark for 250 mcg

This calculator is for research purposes only. Always verify calculations and consult protocols.

Quality Indicators

White lyophilized powder

Should appear as uniform white powder.

Clear reconstituted solution

No particles or cloudiness after mixing.

Third-party COA

Certificate of analysis showing >95% purity.

Research compound only

No human clinical trials - use with caution.

Discoloration

Yellow or brown color indicates degradation.

What to Expect

  • Week 1-2: Subtle cognitive improvements may begin
  • Week 2-4: Enhanced memory and learning capacity
  • Week 4-8: Neurogenesis effects becoming established
  • Week 8-12: Maximum cognitive benefits in animal models
  • Note: Human effects not clinically validated

Side Effects & Safety

Side Effects

  • No human clinical trials - safety profile not established
  • Animal studies show good tolerability
  • May affect other growth factor pathways
  • Long-term effects unknown
  • Not recommended during pregnancy or breastfeeding

When to Stop

  • Unexpected cognitive changes
  • Headaches or neurological symptoms
  • Allergic reactions
  • As directed by healthcare provider

References

3 Studies

Alzheimer's Disease Model (2016)

3xTg-AD mice | Diet supplementation | 5 months | Reversed cognitive deficits, reduced tau

P21 treatment reversed cognitive deficits, increased neurogenesis, enhanced BDNF, and reduced tau pathology in triple-transgenic AD mice.

View Study

Neurogenesis and Synaptic Plasticity (2014)

Aged mice | 50 pmol/g diet | 3 months | Increased dentate neurogenesis

P21 increased hippocampal neurogenesis, dendritic complexity, and synaptic markers in aged mice.

Learning and Memory Enhancement

Mice | Chronic administration | Improved spatial memory

P21 improved performance in Morris water maze and novel object recognition tests.

Quick Start Guide

Typical Dose
50-100mcg daily
How Often
Once daily
Where to Inject
Subcutaneous: abdominal fat
Timing
Morning administration preferred
Effects Timeline
Cognitive improvements: 2-4 weeks; Neurogenesis: 4-8 weeks
Storage
Refrigerate 2-8°C, use within 4 weeks
Cycle Length
4-12 weeks
Break Between
2-4 weeks between cycles

Research Disclaimer

P21 is sold for laboratory research purposes only and is not intended for human or animal consumption. The information provided on this page is compiled from published research, veterinary studies, and anecdotal reports for educational purposes. This content does not constitute medical advice, diagnosis, or treatment recommendations. Any research involving P21 must comply with all applicable local, state, and federal regulations. BioInfinity Lab makes no claims regarding the safety or efficacy of P21 for any purpose. Consult qualified professionals for any research applications.