P21
What it is
P21, also written as P021, is a small synthetic peptide designed as a mimetic of an active region of ciliary neurotrophic factor (CNTF). It was developed in a laboratory setting and typically incorporates a gamma-aminoadamantane (adamantyl) modification and C-terminal amidation, features intended to improve stability and central nervous system access in preclinical work.
Research context and categorization
P21 is generally grouped in the cognitive and neurological research category, and it is often described as a neurogenic or nootropic peptide. In the research literature it is commonly discussed in relation to adult hippocampal neurogenesis, a brain process linked to learning and memory formation. It has been investigated for markers of neuroplasticity, dendritic spine density, and neurotrophic signaling in rodent models, and studied in the context of tau-related and CNTF-mimetic pathways.
These uses are investigational. Reported activity to date comes from preclinical animal studies, largely from a single research group, and no human clinical trials have established that P21 is safe or effective for any use. Any effects described in the literature are unconfirmed and not approved.
Status
- Regulatory status: Research-only. P21 is not FDA-approved for any indication and is treated as an investigational compound.
- Sport status: Not specifically named on the WADA Prohibited List. However, as a CNTF-derived growth-factor mimetic it would plausibly fall under WADA class S2 (peptide hormones, growth factors, related substances and mimetics), and as a non-approved substance it may also be captured under class S0. Anyone subject to anti-doping rules should treat it as prohibited unless a governing body confirms otherwise.
Reconstitution notes (general)
P21 is typically supplied as a lyophilized (freeze-dried) powder that is reconstituted with bacteriostatic water before measurement. Final concentration follows a simple relationship: concentration equals the milligrams of peptide in the vial divided by the millilitres of bacteriostatic water added. For example, more water yields a lower concentration and less water yields a higher one. A reconstitution calculator is available at /pages/tools.
Dilution and handling notes (compound-specific)
Reported reconstitution volumes for P21 commonly target a working concentration in the range of roughly 1 to 2 mg/mL. As an illustration, a 5 mg vial reconstituted with 5 mL of bacteriostatic water gives about 1 mg/mL, while 2.5 mL gives about 2 mg/mL. This range is described as a practical balance: concentrated enough for precise measurement, yet dilute enough to limit irritation in handling.
P21 generally dissolves readily in bacteriostatic or sterile water and should form a clear solution after gentle swirling. Because the molecule carries a hydrophobic adamantyl group, it can be somewhat less water-friendly than simple peptides. If full dissolution is difficult, a common laboratory approach is to introduce a very small amount of a co-solvent such as DMSO before adding the aqueous buffer, then bring it to volume. Add the water slowly against the inner glass wall rather than directly onto the powder, and swirl rather than shake. If the solution stays cloudy, shows particles, or will not clear, it should not be used.
Handling and storage
Store reconstituted P21 refrigerated at 2 to 8 C and keep it out of direct light. Wipe the vial stopper with an alcohol swab before each access and let it air-dry. Label the vial with the mix date. A refrigerated working solution is generally considered usable for roughly a 4-week window. Do not freeze the reconstituted solution, as freeze-thaw cycles can degrade peptides. Discard the vial if the contents become cloudy or discolored, or if floaters or particles appear.
Related reading
Tools and supplies
- Reconstitution & blend calculators
- Bacteriostatic Water 30 ml
- Gansulin Metal Reusable Pen
- 3 ml Glass Cartridges (10-pack)
- Complete Starter Kit
For laboratory and research reference only. Educational content, not medical, dosing, injection, or therapeutic guidance, and not intended for human or animal use. Any research uses described are investigational and not confirmed or approved benefits. Confirm anything involving health with a licensed professional. References linked above.