P21
Also known as: P021
P21 is a research neurogenic and nootropic compound derived from ciliary neurotrophic factor (CNTF), studied preclinically for reported effects on neurogenesis and memory. It is not an approved medicine in Australia.
- Category
- Cognitive / Nootropic
- Reported half-life
- Not well established in humans
- Common forms
- Oral capsules or powder (research/grey-market), Reconstituted injectable solution for subcutaneous use (research)
- Research status
- Research neurogenic/nootropic compound; NOT approved for human use in Australia. Evidence is largely preclinical (cell and animal data), and human safety and effectiveness are not established.
- Last updated
- 21 June 2026
Claimed effects
The following effects are reported or claimed by users and in early research. They are not established medical facts and many are not supported by large human trials.
- Reported in animal studies to be associated with increased neurogenesis
- Reported in preclinical work to influence BDNF-related signalling
- Users report cognitive and memory-related effects, though human trial data is limited
- Reported to mimic an active region of ciliary neurotrophic factor (CNTF)
How it is reported to work
P21 is a CNTF-derived compound reported to mimic an active fragment of ciliary neurotrophic factor. It is proposed to promote the growth of new neurons (neurogenesis) and to increase brain-derived neurotrophic factor (BDNF) signalling, which is linked to learning and memory in animal models. These mechanisms come mainly from cell and animal research and should be regarded as preliminary.
What is P21?
P21 (also written P021) is a research neurogenic and nootropic compound derived from ciliary neurotrophic factor (CNTF), studied preclinically for reported effects on the growth of new neurons and on memory. It is not an approved medicine in Australia. This page is educational information, not medical advice, and every effect below is a reported claim, not an established fact.
How does P21 work?
It is reported to mimic an active fragment of CNTF and to promote neurogenesis and BDNF signalling, both linked to learning and memory in animal models. This is a cell- and animal-derived mechanism and should be treated as preliminary rather than proven in humans.
What does the research show?
Most available evidence comes from cell and animal studies rather than large human trials.
| Evidence type | Status |
|---|---|
| Laboratory (in vitro) studies | Present |
| Animal studies | Present |
| Large human clinical trials | Limited/absent |
| Australian medicine approval | Not approved |
Because human data is limited, reported cognitive “results” are anecdotal and should not be read as proof of benefit or safety.
What do people use it for (reported)?
P21 is reported to be used for cognitive support, memory and focus in nootropic contexts. These are reported uses, not validated clinical outcomes, and nothing here encourages use.
Is P21 safe?
Its safety in humans is not established. There are no large human trials, long-term risks are unknown, and grey-market products cannot be verified for purity or identity by consumers. Reported side effects include headaches and changes in mood, alertness or sleep. Because raw powder and reconstituted vials can vary in concentration and purity, independent testing is often discussed in the research community for compounds like this. This article explains what P21 is; it does not recommend obtaining or using it, and all effects described remain reported claims. Anyone with cognitive or neurological concerns should consult a qualified healthcare professional.
Reported positives & side effects
Compiled from research and community reports. These are reported outcomes, not guarantees or medical advice, individual experiences vary widely.
Reported positives
- Reported in animal studies to be associated with increased neurogenesis
- Reported in preclinical work to influence BDNF and memory pathways
- Reported interest for cognitive support in research contexts
- Reported availability in both oral and injectable research forms
Common side effects
- Reported mild headaches
- Reported changes in mood or alertness
- Reported sleep disturbance in some users
- Reported injection-site reactions when used subcutaneously
Rare / serious side effects
- Unknown long-term risks given the absence of human trials
- Reported reactions to contaminated or mislabelled grey-market product
- Reported unpredictable effects due to unverified purity and dosing
Reported misuse & overdose risks
What has been reported to happen with overuse, excessive dosing, or long-term misuse of P21. Listed so you can make an informed decision, not to suggest any use is safe.
- Reported use of doses above studied ranges in pursuit of stronger cognitive effects
- Reported stacking with multiple other nootropics, amplifying side-effect and interaction risk
- Reported dosing errors from unverified raw powder of unknown concentration
- Reported prolonged continuous use without any human long-term safety data
Reported results timeline
Roughly how long people report it takes to notice effects. A general guide from reports, not a promise, and not advice. Users typically report subtle cognitive or mood changes over a few weeks of consistent use, though human evidence is limited.
First effects
Some report subtle cognitive or mood changes in the first weeks
Noticeable change
Reported effects described over ~4-6 weeks of consistent use
Clear results
Reported effects over a longer cycle, though human data is limited
Commonly reported dosing & protocol
Reported figures only, NOT a recommendation or dosing advice. These are numbers people report using, compiled for education so you can make an informed decision. We do not advise anyone to take P21. Many peptides are not approved for human use in Australia. Speak to a qualified healthcare professional.
| Route | Oral or subcutaneous injection (research) |
|---|---|
| Typical reported dose | Reported roughly 0.5-1 mg per dose |
| Frequency | Reported once daily |
| Cycle length | Reported multi-week cycles (e.g. 4-8 weeks) followed by a break |
Reported reconstitution (mg → units)
For subcutaneous use (example only, not a recommendation): a 5 mg vial reconstituted with 2.5 mL bacteriostatic water gives 2 mg/mL (5 ÷ 2.5 = 2). A 1 mg dose would be 0.5 mL = 50 units on a U-100 insulin syringe (1 ÷ 2 = 0.5 mL; 0.5 × 100 = 50 units). Oral forms need no reconstitution.
Work out the units for your vial → CalculatorReported community use is commonly described as a daily oral or subcutaneous dose taken over a multi-week cycle, sometimes followed by a break. These are reported patterns only, not a recommendation, and no human dosing has been validated in clinical trials.
Best used with / commonly stacked with
Combinations people report using together. Reported, not recommended, stacking can increase risks.
Safety notes
P21 is a research compound and is not an approved medicine in Australia. There are no large human trials establishing its safety, and grey-market products cannot be verified for purity or identity by consumers. This page is educational and is not medical advice. Anyone with cognitive or neurological concerns should consult a qualified healthcare professional.