Table 2.

Randomised controlled trials investigating the effect of intravenous vitamin C (IVC) in patients with COVID-19.

Population Mean Age Location	Intervention Duration	Findings (IVC vs. Control)	Reference
54 patients with COVID-19-pneumonia and multiple organ injury Age = 67 ± 13 years Wuhan, Hubei, China	IVC 1 24 g/day (n = 27) or placebo (n= 29) for 7 days	Higher PaO2/FiO2 2 (229 vs. 151 mmHg, p = 0.01) Lower Interleukin-6 (19 vs. 158 pg/mL, p = 0.04) Lower ICU 3 and hospital mortality in patients with SOFA 4 scores ≥3 (4 vs. 10 days, p = 0.03) No difference in ventilation-free days (26.5 vs. 10.5 days, p = 0.56)	[28]
150 patients with severe COVID-19 Age = 52–53 years Karachi, Pakistan	IVC 50 mg/kg/day + standard therapy or standard therapy (75 per group)	Patients became symptom-free earlier (7.1 ± 1.8 vs. 9.6 ± 2.1 days, p < 0.0001) Patients spent fewer days in the hospital (8.1 ± 1.8 vs. 10.7 ± 2.2 days, p < 0.0001) No difference in need for mechanical ventilation (16% vs. 20%, p = 0.4) No difference in mortality (9.3% vs. 14.6%, p = 0.3)	[30]
60 patients with COVID-19 Age = 57–61 years Tehran, Iran	IVC 6 g/day + standard therapy or standard therapy (30 per group) for 5 days	Lower body temperature on 3rd day of hospitalisation (p = 0.001) Improvement in oxygen saturation on 3rd day of hospitalisation (p = 0.014) No differences in length of ICU stay or mortality	[31]

¹ IVC: intravenous vitamin C, ² PaO₂/FiO₂: ratio of partial pressure of oxygen to fraction of inspired oxygen, ³ ICU: intensive care unit, ⁴ SOFA: sequential organ failure assessment.