P21

P21 is a synthetic peptide-like compound derived from the active region of ciliary neurotrophic factor (CNTF), designed to promote neurogenesis while being brain-penetrant after systemic administration. Unlike the large CNTF protein, P21 crosses the blood-brain barrier effectively, enabling peripheral dosing for central effects.

Research has demonstrated P21 significantly increases neurogenesis in the adult hippocampus, a brain region critical for memory formation and emotional regulation. The compound promotes proliferation of neural progenitor cells and their differentiation into mature neurons, a process that normally declines with age.

P21's neurogenic effects are accompanied by anti-neuroinflammatory activity, including reduction of activated microglia and pro-inflammatory cytokine expression. This dual action on neurogenesis and neuroinflammation may provide synergistic benefit in age-related cognitive decline and neurodegenerative conditions.

Animal studies have shown P21 improves cognitive performance in various behavioral tests, including spatial memory and object recognition. These effects correlate with increased BDNF expression and enhanced synaptic plasticity, suggesting P21 activates multiple neurotrophic pathways to support brain health and cognitive function.