Is Overdosing on vitamin C possible?

Since the start of coronavirus disease 2019 “COVID-19” pandemic, multiple treatment regimens have been tried under the compassionate use indications. So far, no specific antiviral drug has been proven to be effective, apart from remdesivir which showed promising results and has gained an emergency approval by Food and Drug Administration (FDA) to be used in the treatment of COVID-19. Many of are encouraged to build immunity support by taking supplements, however is overdosing possible?

That is why supportive treatment, including supplementation of micronutrients such as vitamin C, has become a crucial part in management of COVID-19. It is noticed that levels of vitamin C is depleted during the acute stage of the infection. Clinical trials have found that supplementation with high dose of vitamin C decreased the severity and duration of respiratory viral infections. Based on these findings, vitamin C might be used in management of COVID-19 as it might improve the immunological response against the novel coronavirus (SARS-CoV-2).

The recommended daily allowance of vitamin C for adults is 90 mg/day. During acute infection, a higher dose of vitamin C is required to meet the increased metabolic demand. According to the United States nutritional recommendation, the tolerable upper limit of the daily dose of vitamin C is 2 g. Doses higher than 2 g/day can cause diarrhoea, abdominal pain and nausea, which are self-limited once the dose is reduced.

There is a concern that high dose of vitamin C (10 g/day) could lead to a buildup of a higher than normal  level of vitamin C which creates Oxalate, a bodily waste product that rids you of excess vitamin C, normally through urine. In some cases, it can bind to minerals and form crystals, which may cause kidney stones. Vitamin C is water soluble, therefore, intoxication due to excessive intake of vitamin C is unlikely as the concentration of vitamin C which exceeds the body daily requirement will be excreted by the kidneys.

Overdosing on vitamin C usually occurs from taking it in supplement form, which is why experts recommend ingesting most of your vitamin C through food, where the chances of getting too much are virtually zero. To avoid this, eat a balanced diet of fruits, vegetables, and lean meats, which should provide you with enough vitamin C naturally.