Cognitive
P21
Longevity
4
Amino acids
Molecular weight
Peptide
Type
P21 is a nootropic peptide derived from ciliary neurotrophic factor (CNTF) that enhances neurogenesis and cognitive function. It contains an adamantane moiety that enables blood-brain barrier penetration. Research shows it increases BDNF expression, inhibits LIF signaling to promote neurogenesis, and reduces tau and amyloid pathology in Alzheimer's disease models. Remarkably, P21 can boost neurogenesis in diseased brains above levels seen in healthy untreated brains.
Top researched benefits
Overview of P21
P21 operates through multiple pathways: it inhibits leukemia inhibitory factor (LIF) signaling, removing a key roadblock to neurogenesis and shifting the brain toward a more embryologic state favoring neuron growth. It increases brain-derived neurotrophic factor (BDNF) expression and activates the BDNF/TrkB/PI3-K/AKT/GSK3β pathway. This pathway modulation improves cognitive function and reduces tau and amyloid pathologies.
neurodegenerative disease
- P021 markedly reduced tau pathology, attenuated Aβ generation, and rescued episodic memory impairment in 3xTg-AD mice.
- Treatment during synaptic compensation period can prevent neurodegeneration and reduce mortality.
- Robust attenuation of tau pathologies through BDNF/TrkB/PI3-K/AKT/GSK3β pathway.
cognitive enhancement
- Enhances dentate gyrus neurogenesis so effectively it exceeds levels in healthy untreated brains.
- Enhances memory processes through increased BDNF and restored synaptic function.
- May reduce natural decline in learning and memory in aged models by rescuing neurogenesis deficit.
neuroprotection
- Restores synaptic deficits in cortex and hippocampus.
- Rescues deficits in neuronal plasticity.
Typical Dose
Research compound - dosing not established for humans
Frequency
Daily in animal research protocols
Cycle Duration
Not established - experimental peptide without human trials
Storage
Refrigerate at 2-8°C
Chemical Makeup
Key benefits
Potent promotion of neurogenesis in the dentate gyrus
Increased BDNF expression
Reduced tau protein pathology
Reduced amyloid-beta plaque formation
Improved cognitive function and memory
Restored synaptic deficits in cortex and hippocampus
Reduced mortality rate in AD models
Crosses blood-brain barrier effectively
Community interest
This peptide is still gaining traction in the community.
P021 | CNTF-Derived Neurogenic Peptide
This overview is informational and based on aggregated descriptions from studies and user reports.
Was it helpful?YesNoP21 Molecular Information
View the scientifc details of P21.
4
Amino Acids
P21
Asp
Asp
Position 1
Gly
Gly
Position 2
Gly
Gly
Position 3
Leu
Leu
Position 4
Molecular Weight
578.7DaChain Length
4Amino AcidsType
PeptideP21 Protocols
P21 has not yet been tested in human clinical trials. Research protocols in animal models use subcutaneous or intraperitoneal injection. The adamantane moiety enables blood-brain barrier penetration for CNS effects.
| Goal | Dosage | Frequency | Route |
|---|---|---|---|
| Research protocol | — | 1 week range | SubQ or IP |
Reconstitution Instructions
Materials needed:
Steps to reconstitute
- Clean work area and hands thoroughly
- Calculate required BAC water volume
- Draw BAC water into syringe
- Inject slowly down vial side
- Gently swirl until dissolved (never shake)
- Store in refrigerator
P21 Cycle
The P21 Cycle section explains how long a typical cycle lasts and what to expect during each phase. Over time, your body can become less responsive with continuous use.
Taking breaks between cycles may help maintain effectiveness and support better overall results.
- Week 0-0
- BDNF elevation begins
- Week 0-0
- Neurogenesis enhancement measurable
- Week 0-0
- Cognitive improvements in research models
- Week 0-0
- Disease-modifying effects in AD models
Dosing tools
P21 Peptide Dosage Calculator
Calculate peptide doses with our visual syringe guide.
mg
Enter the total amount of peptide in the vial in milligrams (as stated on the label).
The dose you want to inject per administration, in mcg or mg.
1,000 mcg = 1 mg
1 mL
2 mL
3 mL
5 mL
Custom
Volume of bacteriostatic water you add to reconstitute the powder. Use BAC water for preservation.
Injection Results
Based on your vial and dilution inputs.
P21
SINGLE COMPOUNDVolume per injection
0.05
mL
Concentration
10.00
mg/mL
Doses per vial
20
doses
Total injections per vial
20 injections
How it works
Based on a 10 mg P21 vial diluted with 1 mL of bacteriostatic water, each 500 mcg injection equals 0.05 mL.
1mL / 100 units
5 units
0.050 mL
Reference Guide
Dosing Cycle
- Peptide
- P21
- Dosing
- Research compound - dosing not established for humans
- Dosing Frequency
- Daily in animal research protocols
- Cycle Duration
- Not established - experimental peptide without human trials
- Storage
- Refrigerate at 2-8°C
Note: Triple agonist; microdose for fewer side effects
Reconstitution Tips
- Use bacteriostatic water (BAC) — contains 0.9% benzyl alcohol for preservation
- Inject water slowly — aim down the vial wall, not directly onto powder
- Never shake — gently swirl or roll the vial until dissolved
- Store properly — refrigerate at 2-8°C after reconstitution
- Use within 28 days — most reconstituted peptides remain stable for about 4 weeks
- Keep sterile — always clean vial tops with alcohol before drawing
Peptide Interactions
Research suggestions of P21 interactions with other common peptides and substances.
Cognitive
dih
Longevity
Dihexa
COMPATIBLE
Both promote neurogenesis through different pathways.
Cognitive
sema
Longevity
Semax
COMPATIBLE
Different nootropic mechanisms; may complement each other.
Side effects
Contraindications
Not approved for human use
Pregnancy or breastfeeding
Unknown safety profile in humans
Stop signs
Allergic reactions
Unusual neurological symptoms
Bad signs
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Frequently asked questions
What is a peptide dosage calculator?
A peptide dosage calculator is a free tool that converts your vial size, bacteriostatic water volume, and target dose into an exact syringe draw volume. Instead of doing the reconstitution math by hand, you enter three inputs and instantly get the concentration of your solution and how many milliliters or syringeunits to draw. This calculator works for single peptide compounds and multi-peptide blends.
How do I calculate peptide dosage from a vial?
To calculate your peptide dose, divide the total peptide content of your vial in micrograms by the volume of bacteriostatic water you added in milliliters. This gives you your solution concentration in mcg/mL. Then divide your target dose by that concentration to get your draw volume. For example, a 5mg (5,000 mcg) vial reconstituted with 2mL of BAC water gives a concentration of 2,500 mcg/mL. A 250 mcg dose would require drawing 0.1mL. This calculator automates all of those steps instantly.
How much Bacteriostatic water should I add to a peptide vial?
Most people add 2mL to 3mL of bacteriostatic water per vial, but the right amount depends on the dose you want to draw and the syringe size you are using. Adding 1mL to a 5mg vial gives you a concentration of 5,000 mcg/mL, making each dose very small in volume. Adding 2mL gives you 2,500 mcg/mL, which is easier to measure on a standard insulin syringe. A general guideline is to choose a volume that puts your typical dose somewhere between 10 and 30 units on a U-100 syringe. Use the calculator above to test different water volumes and find what works for your dose.
How are peptides different from proteins?
Both are made of amino acids, but peptides are much smaller than proteins. Because of their tiny size, peptides can act like tiny messengers in the body, sending specific signals to your cells to tell them exactly what to do.
P21Research References
P21 is an emerging compound
P21
P21 is an emerging compound
P021 Treatment in 3xTg-AD Mice
P021 markedly reduced tau pathology, attenuated Aβ, rescued episodic memory, and reduced mortality in AD mice.
n.d.
P21 and BDNF/TrkB Pathway
Disease-modifying effect via BDNF/TrkB/PI3-K/AKT/GSK3β pathway; rescued neurogenesis and cognition.
n.d.
P21 in Cognitive Aging
May reduce age-related cognitive decline by restoring BDNF expression and synaptic function.
n.d.
P21 as Promising AD Drug Candidate
Beneficial effects in preclinical studies make P21 highly promising for AD drug development.
n.d.