Effect of Vitamin D Supplementation on Glutathione Peroxidase (GPx) Activity, Interleukin-6 (IL-6) Levels and Clinical Outcomes in Post-COVID-19 Patients

This clinical pilot study administered and compared daily and bolus dosing regi-mens of vitamin D to achieve and maintain optimal serum levels of 25(OH)D in post-COVID patients. The daily dose group received constant and gradual supplementation of cholecalciferol, intended to achieve more stable 25(OH)D levels without peaks. Conversely, the bolus group received a weekly dose that could lead to rapid increases followed by gradual declines in 25(OH)D levels. The Daily dose of cholecalciferol was calculated using the following formula: Daily dose of cholecalciferol = \[Weight (kg) × desired increase in 25(OH)D (ng/ml) × 2.5\] - 10 .