Vitamin C

Last review completed on
February 14th, 2021

Vitamin C is a potent antioxidant and contributes to immune defence by supporting various cellular functions of the immune system. It is well documented that COVID-19 infections strain the immune system. However, the support for vitamin C had been mostly theoretical until this point, but recent studies have shown that its use in COVID-19 infections may be limited.

Recommendation

As seen below a recent randomized control trial showed that vitamin C had no additional benefits over placebo.

Level of Evidence
= Supporting use article = Neutral Article  = Contradicting use article

Step 1 - In vitro SARS CoV-1/2 and MERS-CoV Step 2 - In vivo MERS-CoV Step 3 - In vivo SARS CoV-2
Equivocal article

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Major Peer-Reviewed Studies

Level 5: Random Controlled Trial SARS CoV-2 articles listed below Randomized Control Trials:

  1.  “Effect of High-Dose Zinc and Ascorbic Acid Supplementation vs Usual Care on Symptom Length and Reduction Among Ambulatory Patients With SARS-CoV-2 Infection”

    Thomas S, Patel D, Bittel B, et al. Effect of High-Dose Zinc and Ascorbic Acid Supplementation vs Usual Care on Symptom Length and Reduction Among Ambulatory Patients With SARS-CoV-2 Infection: The COVID A to Z Randomized Clinical Trial. JAMA Netw Open. 2021;4(2):e210369. doi:10.1001/jamanetworkopen.2021.0369

    This study looked to determine whether high-dose zinc and/or high-dose vitamin C reduced the severity or duration of COVID-19 compared to standard outpatient care. This was a multicenter, single health system randomized clinical factorial open-label trial of 214 patients with confirmed COVID-19 infections. Patients were randomized to either receive 10 days of zinc gluconate (50 mg), ascorbic acid (8000 mg), both agents, or standard of care. It was found that none of the interventions significantly decreased the duration of COVID-19 symptoms compared to standard care.

Ongoing clinical trials

  1. “High-Dose Vitamin C Treatment in Critically Ill COVID-19 Patients”
  2. “Use of Ascorbic Acid in Patients With COVID 19”
  3. “The Effect of Melatonin and Vitamin C on COVID-19”
  4. “Lessening Organ Dysfunction With VITamin C - COVID-19 (LOVIT-COVID)”
  5. “RCT, Double Blind, Placebo to Evaluate the Effect of Zinc and Ascorbic Acid Supplementation in COVID-19 Positive Hospitalized Patients in BSMMU”
  6. “Administration of Intravenous Vitamin C in Novel Coronavirus Infection (COVID-19) and Decreased Oxygenation (AVoCaDO)”
  7. “SAFEty Study of Early Infusion of Vitamin C for Treatment of Novel Coronavirus Acute Lung Injury (SAFE EVICT CORONA-ALI)”
Adjunctive therapy