Vitamin C (ascorbic acid) has wide ranging actions on our body as an antioxidant, immunomodulator, co-factor for collagen and hormone production, and as a pro-oxidant burst in high doses.1 Vitamin C is well established for its treatment of infections and has been shown to shorten the duration of the common cold as well as reducing symptoms of bacterial infections.2,3 It also acts as a protectant for lung tissue function during viral illness, especially relevant to COVID-19 patients. Recently, intravenous (IV) vitamin C has shown benefit in reducing mortality from sepsis4,5, reducing oxidative stress in the critically ill6,7 and reducing the duration of mechanical ventilator use and ICU hospital stays.8,9

The exciting news is currently there are positive reports of hospitals in Shanghai, Wuhan, South Korea, and New York using IV dosing of vitamin C to help critically-ill SARS-Covid-2 patients recover faster.10,11,12,26 When vitamin C is infused, it bypasses the digestive system to allow for increased dose tolerance and peak serum concentrations at 350 mg/dL, 100 times greater than oral peak levels.13 The Shanghai consensus states that doctors are infusing vitamin C at 100 mg/kg dosing over 24 hours, which is about 7,000 mg vitamin C for a 155-pound person; not a large dose by any stretch.10,11,13 

Vitamin C is also relatively inexpensive when compared to other standard interventions. An average treatment would cost under $25 per person per day.11 With this encouraging news, several clinical trials around the world have started to continue to assess the efficacy of vitamin C as an adjunctive treatment option.14,15,16

Vitamin C is an essential vitamin that we cannot make on our own; thus, the need to replenish our levels frequently through food or other sources. The current recommended daily allowance in healthy adults is 2,000 mg.3 However, vitamin C deficiency is common in critically-ill patients.17 When our bodies are in a stressed state, such as when we are ill, it triggers an inflammatory response and more vitamin C is needed to modulate the oxidative damage.18,19 

Dose tolerance for oral vitamin C depends on the individual and can vary between 100 mg to 10,000 mg due to the osmotic effect it has on the digestive system. Gastrointestinal cramping and loose stools are common complaints for high oral intake.3,17 In my clinical experience, patients in the cancer arena20,21,22 have had 25,000-100,000 mg of vitamin C safely infused over a four- hour time frame without any adverse effects. 

Because vitamin C is a water-soluble vitamin and readily used or eliminated in our body, it is difficult to build up toxic doses. Currently there is a high level of safety, no standard lethal dose of vitamin C for humans and no reported deaths from vitamin C toxicity,23,24 despite what some news headlines say.25 In some cases, doses of vitamin C over 10,000 mg could cause hemolytic anemia in those with a genetic mutation of the specific enzyme G6PD. So, medical professionals should test patients prior to initial infusion. This is done through a standard blood test. Patients with underlying kidney issues also need monitoring for higher doses.21,22 

For patients with moderate to severe COVID-19, vitamin C is a safe, well-tolerated, efficacious and relatively inexpensive treatment protocol that all hospitals are capable of implementing as an adjunct to current in-hospital treatment protocols to reduce ventilator usage, ICU stays and infections.26,27 

We should be encouraged by the data shared through the Shanghai consensus and the potential benefits for patients with moderate to severe COVID-19 symptoms utilizing IV vitamin C therapy. 

Dr. Fung is a primary care naturopathic doctor at Live Well Clinic in La Quinta. She has a focus on integrative cancer care and PRP regenerative joint injections for pain and can be reached at (760) 771.5970.

2) Mousavi S, Bereswill S, Heimesaat, M. Immunomodulatory and Antimicrobial Effects of Vitamin C. Eur J Microbiol Immunol (Bp). 2019 Oct 3; 9(3): 73–79. Published online 2019 Aug 16. doi: 10.1556/1886.2019.00016 PMCID: PMC6798581 PMID: 31662885;
3) Linus Pauling Institute- OSU- Vitamin C-;
4) Fowler, Effect of Vitamin C Infusion on Organ Failure and Biomarkers of Inflammation and Vascular Injury in Patients With Sepsis and Severe Acute Respiratory Failure: The CITRIS-ALI Randomized Clinical Trial. JAMA, 2019; 322 (13): 1261 DOI:10.1001/jama.2019.11825;
5) Ren, Vitamin C: a misunderstood ally? Crit Care. 2020; 24: 8. Published online 2020 Jan 7. doi: 10.1186/s13054-020-2725-x PMID: 31910873;
6) Meyer, M., Jaspers, I. Respiratory protease/antiprotease balance determines susceptibility to viral infection and can be modified by nutritional antioxidants. Am J Physiol Lung Cell Mol Physiol. 2015 Jun 15; 308(12): L1189–L1201. doi: 10.1152/ajplung.00028.2015 PMID: 25888573;
7) Fowler, Intravenous vitamin C as adjunctive therapy for enterovirus/rhinovirus induced acute respiratory distress syndrome. World J Crit Care Med 2017; 6(1): 85-90;
8) Hemilä H, Chalker E. Vitamin C Can Shorten the Length of Stay in the ICU: A Meta-Analysis. Nutrients. 2019 Apr; 11(4): 708. Published online 2019 Mar 27. doi: 10.3390/nu11040708 PMID: 30934660;
9) Hemilä H, Chalker E. Vitamin C may reduce the duration of mechanical ventilation in critically ill patients: a meta-regression analysis-;
11) Anderson, Paul. Intravenous Ascorbic Acid (IVAA) for COVID-19 Supportive Treatment in Hospitalized COVID-19 Patients (Based on use in China and US settings) March 2020;
12) Mongelli, Lorena. Golding, Bruce.  New York hospitals treating coronavirus patients with vitamin C. 24 March 2020. New York Post;
13) Stephenson CM, Phase I Clinical Trial to evaluate the safety, tolerability, and pharmacokinetics of high-dose intravenous ascorbic acid in patients with advanced cancer. Cancer Chemother Pharmacol. 2013; 72(1):139-146.;
14) Use of Ascorbic Acid in Patients With COVID 19- Italy;
15) Vitamin C Infusion for the Treatment of Severe 2019-nCoV Infected Pneumonia- China;
16) Lessening Organ Dysfunction With VITamin C (LOVIT)- Quebec, Canada;
17) Merck Manual- Vitamin C Deficiency- Larry E. Johnson MD, PhD,-dependency,-and-toxicity/vitamin-c-deficiency;
18) Carr A, Maggini S. Vitamin C and Immune Function; Nutrients. 2017 Nov; 9(11): 1211. Published online 2017 Nov 3. doi: 10.3390/nu9111211  PMID: 29099763;
19) Hemila H. Vitamin C and Infections. Nutrients 2017 Apr; 9(4): 339. Published online 2017 Mar 29. doi: 10.3390/nu9040339 PMID: 28353648.;
20) Wang J, Wu F and Corpe C (2019) Editorial: Vitamin C in Cancer and Infectious Diseases: Physiological, Biochemical and Therapeutic Interventions. Front. Physiol. 10:734. doi:10.3389/fphys.2019.00734;
21) NCI- High-Dose Vitamin C (PDQ®)–Health Professional Version-;
22) Parmar G, Kaczor T. Textbook of Naturopathic Oncology. Medicatrix Holdings, 2020;
26) Cheng, Richard. Successful High-Dose Vitamin C Treatment of Patients with Serious and Critical COVID-19 Infection- Orthomolecular Medicine News Service, Mar 18, 2020;
27) Orthomolecular Medicine News Service, Apr 3, 2020- Editorial: Rationale for Vitamin C Treatment of COVID-19 and Other Viruses-

Read or write a comment

Comments (0)


Living Wellness with Jenniferbanner your financial health michelle sarnamentoring the futureNaturopathic Family Medicine with Dr. ShannonThe Paradigm Shift in Medicine TodayConventionally Unconventional with Kinder Fayssoux, MD