Photobiomodulation for cognitive dysfunction (Brain Fog) in post-COVID-19 condition: a randomized double-blind sham-controlled pilot trial

Background: Post-COVID-19 condition (PCC) affects millions globally, with cognitive dysfunction ("brain fog") impairing daily functioning in up to 88% of patients. No effective treatments exist for PCC-related cognitive impairment. Photobiomodulation (PBM), a non-invasive therapy delivering near-infrared light, enhances mitochondrial function and reduces neuroinflammation, showing promise in neurological disorders. This study aimed to evaluate the efficacy and safety of home-based intranasal and transcranial PBM (itPBM) for PCC cognitive dysfunction. Methods: This randomized, double-blind, sham-controlled pilot trial in the USA (ClinicalTrials.govNCT05857124) enrolled 43 adults (18-65 years) with PCC cognitive symptoms ≥12 weeks post-infection. Participants were randomized 1:1, stratified by age (