Exosomes in Bell's Palsy: A narrative review of mechanisms, evidence, and clinical translation

Bell’s palsy is the most common cause of acute peripheral facial paralysis. Although most patients recover with timely standard corticosteroid-based treatment, some develop persistent weakness, facial asymmetry, or synkinesis. Exosome-enriched extracellular vesicles are investigational cell-free candidates for nerve repair because they may modulate inflammation, support Schwann-cell activity, and promote axonal regeneration and remyelination. This narrative review summarizes mechanistic, preclinical, and early human evidence for exosome-based approaches in Bell’s palsy and facial nerve repair. Current evidence is mainly derived from facial nerve crush, axotomy, graft-repair, and peripheral nerve injury models, which do not fully reproduce idiopathic Bell’s palsy. Human data remain limited to small uncontrolled studies and case reports, suggesting feasibility but not established efficacy. Exosome therapy is not an approved treatment for Bell’s palsy and requires rigorously designed controlled trials, particularly in high-risk patients with poor prognostic indicators.