P21
Mechanism.
P21 is a small synthetic peptide derived from the active region of ciliary neurotrophic factor (CNTF). It was designed to mimic CNTF's neurotrophic effects while being small enough to cross the blood-brain barrier. Research in animal models of Alzheimer's disease has shown P21 can enhance neurogenesis, reduce neurodegeneration, and improve cognitive function. No human clinical trials have been published.
P21 is like a concentrated extract of a brain growth signal. The full signal (CNTF) is too large to get through the brain's security checkpoint (blood-brain barrier), so scientists designed a miniature version that carries the same message -- 'grow and repair neurons' -- but is small enough to slip through.
How it's taken.
Values below describe how P21 has been administered in published trials and labeling. Provided for educational purposes only — this is not medical advice and not instructions for self-administration. Consult your healthcare provider before making any health decision.
Small peptide derived from CNTF (ciliary neurotrophic factor). Promotes neurogenesis in animal models. No human clinical trials. Research compound only.
Use the free peptide calculator for dilution, unit conversion, and injection volume.
Side effects, rare serious events, who shouldn't.
Every study we cite.
Each study with its published finding and a plain-language note on limitations or funding.