Psilocybin prevents chemotherapy-induced peripheral neuropathy through mitochondrial trafficking preservation.
Chemotherapy-induced peripheral neuropathy (CIPN) is a disabling, often irreversible toxicity that affects millions of patients, limits life-saving cancer therapy, and lacks proven treatment. In this work, we show that as little as two doses of psilocybin before chemotherapy durably prevented the onset of CIPN across platinum- and taxane-based models, including repeated chemotherapy cycles, without impairing antitumor efficacy. Peripherally, psilocybin maintained tactile sensitivity and intraepidermal nerve fiber endings through axonal mitochondrial trafficking and distribution preservation, through the TrkB-Akt-PAK5-MAP2-KIF5B pathway and remobilization of syntaphilin-anchored mitochondria. Centrally, it normalized medial prefrontal cortical synaptic activity and cortical alpha and beta electroencephalography power. This stabilization of peripheral axonal energy balance establishes psilocybin as a first-in-class prophylactic agent for CIPN while also preserving central neural function. Given psilocybin's established safety, these discoveries support clinical evaluation as a strategy to prevent CIPN.