P21 (P021)

What is P21 (P021)?

P21, also written P021, is a lab-designed peptide built from a small piece of ciliary neurotrophic factor, a natural growth factor for nerve cells. Researchers mapped the most active fragment of that protein, then bolted on a bulky adamantane group so the peptide could cross the blood-brain barrier and resist breakdown.

From the BioHarmony report, reviewed 2026-09-08.

How it is thought to work

Raises BDNF and inhibits LIF signaling, which lowers GSK-3beta and reduces tau hyperphosphorylation

Safety watch-outs

• Any new or worsening seizure, aura, or unusual neurological symptom: stop immediately, since growth-factor and neurogenesis modulation has…
• Active or prior cancer: do not use, since chronically raising trophic and pro-proliferative signaling is a theoretical concern with no…
• Injection-site redness, swelling, warmth, or fever: stop and seek care, since grey-market injectables carry sterility and infection risk.
• Any unexpected reaction at all: there is no human safety baseline, so treat anything new as a reason to stop and reassess.

Full risk profile in the BioHarmony report.

Dosing as published

No approved-label or study protocol is recorded for P21 (P021) yet.

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