An important note
No supplement will cure or prevent disease.
With the 2019 coronavirus COVID-19 pandemic, it’s especially important to understand that no supplement, diet, or other lifestyle modification other than physical distancing, also known as social distancing, and proper hygiene practices can protect you from COVID-19.
You may have noticed the vitamin C section of the supplement aisle looking bare these days or seen the claims on social media that vitamin C can help with COVID-19.
While physicians and researchers are studying the effects of high dose intravenous (IV) vitamin C on the new coronavirus, no supplement, including vitamin C, can prevent or treat COVID-19.
This article reviews what vitamin C is, how it affects immunity, how it’s being tried for COVID-19 treatment in a hospital setting, and whether taking an oral supplement is beneficial.
Vitamin C is an essential nutrient with several roles in your body. It’s a potent antioxidant, meaning it can neutralize unstable compounds in your body called free radicals and help prevent or reverse cellular damage caused by these compounds (1Trusted Source).
It’s also involved in a number of biochemical processes, many of which are related to immune health (1Trusted Source).
The Daily Value (DV) for vitamin C is 90 mg per day, but breastfeeding women need an extra 30 mg and people who smoke need an extra 35 mg per day (2).
It’s pretty easy to meet your vitamin C needs through your diet as long as you eat a variety of fruits and vegetables. For example, a single medium orange provides 77% of the DV, and 1 cup (160 grams) of cooked broccoli provides 112% of the DV (3Trusted Source, 4Trusted Source).
How does it affect immunity?
Vitamin C affects your immune health in several ways. Its antioxidant activity can decrease inflammation, which may help improve your immune function (5Trusted Source).
Vitamin C also keeps your skin healthy by boosting collagen production, helping the skin serve as a functional barrier to keep harmful compounds from entering your body. Vitamin C in the skin can also promote wound healing (1Trusted Source).
The vitamin also boosts the activity of phagocytes, immune cells that can “swallow” harmful bacteria and other particles (1Trusted Source).
In addition, it promotes the growth and spread of lymphocytes, a type of immune cell that increases your circulating antibodies, proteins that can attack foreign or harmful substances in your blood (1Trusted Source).
In studies of its effectiveness against viruses that cause the common cold, vitamin C doesn’t appear to make you any less likely to get a cold — but it may help you get over a cold faster and make the symptoms less severe (6Trusted Source).
There’s also some evidence from animal research and case studies in humans that high dose or IV vitamin C can reduce lung inflammation in severe respiratory illnesses caused by H1N1 (“swine flu”) or other viruses (7Trusted Source, 8Trusted Source, 9Trusted Source).
However, these doses were far above the DV, and there’s not enough research to support the use of high dose vitamin C for lung inflammation at this time. You shouldn’t take high doses of vitamin C supplements — even orally — because they can cause side effects like diarrhea (2).