Positive Effects of Vitamin D Supplementation in Patients Hospitalized for COVID-19: A Randomized, Double-Blind, Placebo-Controlled Trial

Nutrients. 2022 Jul 26;14(15):3048. doi: 10.3390/nu14153048.


Retrospective studies showed a relationship between vitamin D status and COVID-19 severity and mortality, with an inverse relation between SARS-CoV-2 positivity and circulating calcifediol levels. The objective of this pilot study was to investigate the effect of vitamin D supplementation on the length of hospital stay and clinical improvement in patients with vitamin D deficiency hospitalized with COVID-19. The study was randomized, double blind and placebo controlled. A total of 50 subjects were enrolled and received, in addition to the best available COVID therapy, either vitamin D (25,000 IU per day over 4 consecutive days, followed by 25,000 IU per week up to 6 weeks) or placebo. The length of hospital stay decreased significantly in the vitamin D group compared to the placebo group (4 days vs. 8 days; p = 0.003). At Day 7, a significantly lower percentage of patients were still hospitalized in the vitamin D group compared to the placebo group (19% vs. 54%; p = 0.0161), and none of the patients treated with vitamin D were hospitalized after 21 days compared to 14% of the patients treated with placebo. Vitamin D significantly reduced the duration of supplemental oxygen among the patients who needed it (4 days vs. 7 days in the placebo group; p = 0.012) and significantly improved the clinical recovery of the patients, as assessed by the WHO scale (p = 0.0048). In conclusion, this study demonstrated that the clinical outcome of COVID-19 patients requiring hospitalization was improved by administration of vitamin D.

Keywords: COVID-19; SARS-CoV-2; calcifediol; cholecalciferol; hospitalization; vitamin D.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • COVID-19*
  • Cholecalciferol / therapeutic use
  • Dietary Supplements
  • Double-Blind Method
  • Hospitalization
  • Humans
  • Pilot Projects
  • Retrospective Studies
  • SARS-CoV-2
  • Vitamin D
  • Vitamins / therapeutic use


  • Vitamins
  • Vitamin D
  • Cholecalciferol

Grants and funding

This research received no external funding.