Intersecting Psychedelic Pharmacology and Gut-Brain Axis Signaling in Neurodegenerative Disorders

Neurodegenerative diseases are marked by progressive neuronal loss, inflammation, and impaired plasticity. Although existing treatments provide limited protection for the brain or ability to slow disease progression, emerging research highlights the gut-brain axis and psychedelics as promising new areas for therapeutic development. The gut microbiome, a metabolically active ecosystem, influences brain function through immune, neural, and endocrine pathways. Gut dysbiosis has been implicated in the pathogenesis of multiple neurodegenerative disorders. Parallel to this, classical psychedelics such as psilocybin and LSD have demonstrated potent neuroplastic, anti-inflammatory, and mood-enhancing effects. Acting primarily via 5-HT₂A receptor activation and BDNF-TrkB-mTOR signaling pathways, these compounds promote neuritogenesis, synaptogenesis, and cognitive flexibility, suggesting therapeutic potential in reversing neurodegenerative pathology. Emerging data reveal that gut microbiota may modulate the pharmacodynamics of psychedelics by affecting bioavailability, immune signaling, and receptor expression. Studies show that altered microbiomes influence psychedelic responsiveness, with certain bacterial taxa. This review explores the triangular interplay between the gut, brain, and psychedelics, proposing a systems-level model in which the gut microbiota acts as both a mediator and modulator of psychedelic efficacy in neurodegeneration. It highlights the potential for microbiome-informed, personalized psychedelic therapies and discusses microbiota-targeted interventions, such as prebiotics, probiotics, and nutritional strategies, as adjunct therapies to enhance therapeutic outcomes. Though preliminary, these findings warrant deeper investigation through clinical trials and mechanistic studies. Psychedelics, when integrated with microbiome science, may redefine therapeutic approaches to brain disorders, offering a transformative opportunity for precision neuropsychiatry and neurology.