Effects of an 8‐week high‐dose vitamin D supplementation on fatigue and neuropsychiatric manifestations in post‐COVID syndrome: A randomized controlled trial

Aim This study evaluated the effectiveness of high‐dose vitamin D supplementation in alleviating fatigue and neuropsychiatric symptoms in post‐COVID syndrome. Methods In an 8‐week, double‐blind, randomized, placebo‐controlled trial, 80 patients with post‐COVID fatigue or neuropsychiatric symptoms were enrolled. Participants were randomly assigned to receive either 60,000 IU of vitamin D weekly ( n = 40) or a placebo ( n = 40) for 8 weeks. Clinical outcomes were assessed using the 11‐item Chalder Fatigue Scale (CFQ‐11); 21‐item Depression, Anxiety, and Stress Scale (DASS‐21); Pittsburgh Sleep Quality Index (PSQI); Addenbrooke's Cognitive Examination III (ACE); and Trail Making Test A and B (TMT‐A and TMT‐B). Baseline and 8‐week measurements of inflammatory markers, including interleukin 6 (IL‐6) and C‐reactive protein (CRP), were also collected. Results Significant improvements were found in the vitamin D group for CFQ (coefficient −3.5, P = 0.024), DASS‐anxiety (−2.0, P = 0.011), and ACE (2.1, P = 0.012). No significant differences were observed in PSQI, DASS‐depression, TMT, IL‐6, or CRP levels. The incidence of adverse events was comparable between groups, with no serious adverse events reported. Conclusion High‐dose vitamin D supplementation may benefit patients with post‐COVID syndrome by reducing fatigue, alleviating anxiety, and improving cognitive symptoms, with minimal side effects.