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Cognitive & neuroprotective

P21 (P021)

Also known as: P021 · Peptide 021

A small peptidergic compound derived from a CNTF motif, commonly cited in the research literature for context around neurogenesis.

P21 (P021) at a glance

NameP21 (P021)
Also known asP021, Peptide 021
CategoryCognitive & neuroprotective
TypePeptide
SequenceCiliary neurotrophic factor (CNTF)-derived peptidomimetic (short modified peptide)
Typical dose~0.5-1 mg per day (figures extrapolated from animal work)
FrequencyOnce daily
RouteSubcutaneous injection (research)
Half-lifeNot well characterized in humans; modifications are described as extending stability.

Overview

P21 (also written P021) is a peptide mimetic based on an active region of ciliary neurotrophic factor (CNTF), with chemical modifications described as improving stability and brain penetration. It has been examined in rodent models of neurodegeneration and memory impairment. There is no established human clinical use, and it is presented here strictly for educational context.

How it’s thought to work

  • Reported to enhance neurogenesis in the hippocampus.
  • Appears to increase brain-derived neurotrophic factor (BDNF) signaling.
  • Studied for inhibition of leukemia inhibitory factor (LIF) signaling and reduction of tau pathology in models.

Researched uses

  • Memory and learning in rodent models
  • Models of Alzheimer-type neurodegeneration
  • General neurogenesis and neuroprotection research

Commonly cited protocol

Typical dose~0.5-1 mg per day (figures extrapolated from animal work)
FrequencyOnce daily
RouteSubcutaneous injection (research)
NotesHuman dosing is not established; cited figures are from preclinical studies scaled loosely.

Reconstitution

For a 5 mg vial reconstituted with 2 mL, the concentration is 2.5 mg/mL, so a 500 mcg dose is about 20 units on a U-100 syringe.

P21 (P021) dosage calculator

The calculator below is pre-filled with P21 (P021)’s commonly cited vial size and dose. Adjust the vial amount, bacteriostatic water, or dose to match your own vial — it will show the exact insulin-syringe units to draw, the concentration, and how many doses the vial holds.

mg
mL
How much water you add is your choice — it doesn’t change your dose, only how many units you draw. Common:
Draw to
20 units
= 0.2 mL on a 1 mL (100 units) syringe
20 units0100
Concentration
2.5 mg/mL
Per unit
25 mcg/u
Doses per vial
10 × 500mcg
Volume
0.2 mL
📋 In plain English

Add 2 mL of bacteriostatic water to your 5 mg vial. That gives you about 10 doses of 500 mcg. For each dose, draw 20 units into a 100-unit insulin syringe.

See the full P21 (P021) dosing chart (units for every dose & water amount), or open the full peptide calculator →

Cautions

  • Not FDA-approved; strictly a research compound.
  • No human clinical data exist.
  • Dosing is speculative and extrapolated from animals.
  • Purity varies by source.

P21 (P021) FAQ

What is P21 (P021)?

A small peptidergic compound derived from a CNTF motif, commonly cited in the research literature for context around neurogenesis.

How does P21 (P021) work?

Reported to enhance neurogenesis in the hippocampus. Appears to increase brain-derived neurotrophic factor (BDNF) signaling. Studied for inhibition of leukemia inhibitory factor (LIF) signaling and reduction of tau pathology in models.

What is P21 (P021) used for?

Memory and learning in rodent models; Models of Alzheimer-type neurodegeneration; General neurogenesis and neuroprotection research.

What is a typical P21 (P021) dose?

~0.5-1 mg per day (figures extrapolated from animal work), Once daily, Subcutaneous injection (research). This is a commonly cited figure for context only, not medical advice.

How do you reconstitute P21 (P021)?

For a 5 mg vial reconstituted with 2 mL, the concentration is 2.5 mg/mL, so a 500 mcg dose is about 20 units on a U-100 syringe.

What is the half-life of P21 (P021)?

Not well characterized in humans; modifications are described as extending stability.

Related cognitive & neuroprotective peptides

⚠️ Educational reference only — not medical advice. These compounds are largely research chemicals not approved for human use in most countries. Nothing here is a recommendation to obtain or administer any substance. Consult a qualified clinician.