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Can Vitamin D Help Fight Coronavirus (COVID-19)?

Written by Mathew Eng, PharmD | Last updated:
Puya Yazdi
Medically reviewed by
Puya Yazdi, MD | Written by Mathew Eng, PharmD | Last updated:

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Besides its benefits to bone health, vitamin D plays an important role in the immune system. Previous studies have even shown that vitamin D may help prevent respiratory tract infections, but can it also protect against the new coronavirus?

The Potential Role of Vitamin D in the COVID-19 Pandemic

First off, there is currently no evidence that vitamin D can treat or prevent the ongoing coronavirus pandemic.

Because the new coronavirus (also known as SARS-CoV-2 or 2019-nCoV) is so new, there is a lack of published studies on possible treatments or prevention strategies.

However, previous research does show that vitamin D plays a critical role in the immune system [1, 2, 3].

In fact, vitamin D deficiency may increase the risk of developing several types of bacterial and viral infections [1, 2, 3].

A number of studies have also found that supplementation with vitamin D may have protective effects against respiratory tract infections, although it’s unknown if this applies to 2019-nCoV as well [4, 5, 6].

While researchers work to identify treatments against 2019-nCoV, the best protective measures you can take are still social distancing, hand washing, and avoiding touching your face.

While a vitamin D deficiency may increase the risk of getting viral infections, research has yet to identify any compounds (including vitamin D) that can effectively treat or prevent the new coronavirus.

Why Your Immune System Needs Vitamin D

Vitamin D is probably most known for its role in calcium and its importance to bone health.

But research is finding more and more that vitamin D has important effects on the immune system [7].

For example, vitamin D can promote the development of certain proteins, such as cathelicidin and beta defensin 4, that have antimicrobial activity [7].

A deficiency of vitamin D can weaken the immune system, potentially increasing the body’s susceptibility to infectious diseases such as coronavirus [1, 2, 3].

A vitamin D deficiency may impair the immune system and potentially increase the risk of infection.

Vitamin D Deficiency

Unfortunately, vitamin D deficiency is very common. According to some estimates, almost 50% of people worldwide do not get enough vitamin D [8].

The primary source of vitamin D is sunlight exposure, which causes a chemical reaction in your skin that produces vitamin D. Other sources include supplements and some types of food [9].

For this reason, people who do not get enough sun exposure are at risk for vitamin D deficiency. Some other risk factors include obesity, dark skin, and older age [9].

Check out this article for information on the best sources of vitamin D and how much you need daily.

Vitamin D deficiency is a worldwide issue. Factors that can increase the risk of deficiency include limited sun exposure, obesity, dark skin, and older age.

Vitamin D May Help In Tuberculosis

Tuberculosis (TB) is a disease caused by an infection from a bacteria called Mycobacterium tuberculosis that mainly affects the lungs.

According to a few clinical trials, supplementation with vitamin D may reduce symptoms and improve the treatment of TB [1].

Overall, however, studies have revealed mixed results. It remains to be seen if vitamin D supplementation has a clinical effect on TB until more research is done [1].

Vitamin D May Protect Against Respiratory Tract Infections

Respiratory tract infections are a group of infectious diseases that affect the sinuses, throat, airways, or lungs. COVID-19, the disease that is caused by the new coronavirus, also belongs in this group [4].

Several large scientific reviews show that vitamin D supplementation may help prevent respiratory tract infections, including the common cold, the flu, and pneumonia [4, 5, 6].

However, the study participants had to take vitamin D on a consistent basis for at least 3 months before any protective effects were seen [4, 5, 6].

It’s unknown if vitamin D supplementation will have the same protective effects against COVID-19.

Vitamin D supplementation has been shown to help prevent respiratory tract infections, but it’s impossible to say if it will help with COVID-19 as well.

Can Vitamin D Be Harmful? The Role of ACE2

The ACE2 gene codes for angiotensin-converting enzyme 2 (a protein also abbreviated ACE2), a protein that sits across the cell membrane in many tissues, including the lungs. Under normal circumstances, it helps reduce blood pressure by converting angiotensin II (which constricts blood vessels) into angiotensin 1-7 (which relaxes blood vessels) [10, 11].

The virus that causes COVID-19, like some other pathogens in the coronavirus family, hijacks the ACE2 protein to gain entry into the cell. Because of this, researchers are currently investigating medications that target ACE2 as potential treatments for COVID-19, but none have been developed so far [12, 13, 14].

In animal studies, vitamin D increased the expression of ACE2 [15, 16].

Increasing ACE2 could theoretically make it easier for the coronavirus to hijack the protein and gain entry to the cell. However, we really don’t know at this point if vitamin D could increase the risk in any way at all.

The safest approach is to just make sure you have sufficient levels of vitamin D (30ng/dl) from getting enough sun, rather than going overboard with supplements.

Vitamin D Dosage

Check with your doctor before taking vitamin D supplements, especially if you have other medical conditions. Vitamin D may have serious interactions with your other medications and health conditions.

Generally speaking, most experts recommend that adults get at least 600 IU of vitamin D each day [9].

Some health professionals recommend 2,000 IU or more a day, though no hard evidence supports this practice.

Check out this vitamin D article for information on dosage & sources.


Vitamin D may help prevent and treat certain types of infection, but there is currently no evidence that vitamin D can help with the new coronavirus.

Many people are deficient in vitamin D, especially those who have limited sun exposure. Those with low vitamin D may need to take supplements to increase their levels.

If your vitamin D levels are low, it probably makes sense to get them to a healthy range ideally with sun and if not supplements so that your immune system is as healthy as possible.

Still, the best protective measures you can take against Coronavirus are social distancing, hand washing, and avoiding touching your face.

Learn more

About the Author

Mathew Eng

Mathew Eng

Mathew received his PharmD from the University of Hawaii and an undergraduate degree in Biology from the University of Washington.
Mathew is a licensed pharmacist with clinical experience in oncology, infectious disease, and diabetes management. He has a passion for personalized patient care and believes that education is essential to living a healthy life. His goal is to motivate individuals to find ways to manage their chronic conditions.

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