Safety and effectiveness of high-dose vitamin C in patients with COVID-19: a randomized open-label clinical trial

Eur J Med Res. 2021 Feb 11;26(1):20. doi: 10.1186/s40001-021-00490-1.


Background: Vitamin C is an essential water-soluble nutrient that functions as a key antioxidant and has been proven to be effective for boosting immunity. In this study, we aimed to assess the efficacy of adding high-dose intravenous vitamin C (HDIVC) to the regimens for patients with severe COVID-19 disease.

Methods: An open-label, randomized, and controlled trial was conducted on patients with severe COVID-19 infection. The case and control treatment groups each consisted of 30 patients. The control group received lopinavir/ritonavir and hydroxychloroquine and the case group received HDIVC (6 g daily) added to the same regimen.

Results: There were no statistically significant differences between two groups with respect to age and gender, laboratory results, and underlying diseases. The mean body temperature was significantly lower in the case group on the 3rd day of hospitalization (p = 0.001). Peripheral capillary oxygen saturations (SpO2) measured at the 3rd day of hospitalization was also higher in the case group receiving HDIVC (p = 0.014). The median length of hospitalization in the case group was significantly longer than the control group (8.5 days vs. 6.5 days) (p = 0.028). There was no significant difference in SpO2 levels at discharge time, the length of intensive care unit (ICU) stay, and mortality between the two groups.

Conclusions: We did not find significantly better outcomes in the group who were treated with HDIVC in addition to the main treatment regimen at discharge. Trial registration (IRCT20200411047025N1), April 14, 2020.

Keywords: 2019-nCoV; COVID-19; Hydroxychloroquine; Lopinavir; Pneumonia; Ritonavir; SARS-COV-2; Vitamin C.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Antiviral Agents / administration & dosage
  • Antiviral Agents / therapeutic use*
  • Ascorbic Acid / administration & dosage*
  • Ascorbic Acid / therapeutic use
  • Body Temperature
  • COVID-19 Drug Treatment*
  • Female
  • Humans
  • Hydroxychloroquine / therapeutic use
  • Intensive Care Units
  • Length of Stay
  • Lopinavir / therapeutic use
  • Male
  • Middle Aged
  • Oxygen / blood
  • Respiratory Distress Syndrome / drug therapy
  • Respiratory Distress Syndrome / virology
  • Ritonavir / therapeutic use
  • Treatment Outcome


  • Antiviral Agents
  • Lopinavir
  • Hydroxychloroquine
  • Ritonavir
  • Ascorbic Acid
  • Oxygen