Can Zinc Help Prevent or Treat COVID-19?

Could dosing up on zinc help stave off or treat COVID-19? The question captivated scientists since the first year of the pandemic. After all, zinc is known for its antiviral effects. It has even been shown to reduce the duration of cold symptoms—and both the common cold and COVID-19 are caused by viruses in the same family, known as coronaviruses. It makes sense to ask: Could zinc be one of the keys to supporting the immune system to prevent and treat COVID-19?

What Is Zinc?

Zinc is an essential nutrient for growth and development, necessary for a strong immune system, wound healing, and proper senses of taste and smell. Children need a source of zinc as soon as they start eating solid foods. They can get the mineral through products like meats, dairy, fish, beans, and zinc-fortified grains.

In North America, zinc deficiency is uncommon, according to the National Institutes of Health (NIH) Office of Dietary Supplements. When it does occur, it's usually due to inadequate intake or absorption of the mineral—and in those cases, eating food rich in zinc or taking a supplement might make sense.

People who are pregnant, vegetarian, or who have certain digestive diseases, are at a greater risk of zinc deficiency. These groups may be more likely to need zinc supplements. But, no matter what group you're in, consult your doctor first.

Because of the nutrient's role in healthy immune system functioning, severe zinc deficiency suppresses the immune system and increases the risk of pneumonia, malaria, and other infections. Zinc's antiviral effects have even been demonstrated against the hepatitis C virus and HIV.

What Have Studies Said About Zinc and COVID-19?

Considering zinc's effects against other viruses, it's unsurprising that scientists would consider its relationship with SARS-CoV-2. Studies suggesting zinc supplementation to control the coronavirus emerged as early as spring 2020. Many retrospective studies correlated low zinc levels in patients' blood with more severe COVID-19. A study published in January 2022 correlated low levels of zinc in surface soils across the US with higher death rates from COVID-19.

But correlation doesn't imply causation. Leo Anthony Celi, MD, principal research scientist at the Massachusetts Institute of Technology, told Health there are "countless examples where fixing some abnormal finding does not change the outcome of a disease." In other words, we don't really know whether "fixing" blood levels of zinc would have any effect whatsoever on how COVID patients fare. Plus, "There may be other factors apart from age, sex, and illness severity that may confound the relationship between serum [blood] zinc levels and outcomes from COVID-19," said Dr. Celi.

What's necessary to establish a causal link between zinc supplementation and COVID-19 occurrence or severity is a randomized controlled trial, the gold standard for clinical trials. According to a review published online in the Journal of Trace Elements in Medicine and Biology in February 2022, no such experiment definitively showed zinc's efficacy. The authors considered both four published clinical trials and 82 unpublished ones, up to January 10, 2022.

In their conclusion to the review, the scientists said that zinc supplementation for COVID-19 prevention or therapy is unjustified as of the date of publication, but noted, "when the results of the ongoing studies are published, this may change our conclusion."

So, Should I Take Zinc Supplements for COVID-19?

As of April 21, 2021, the NIH recommended against "the use of zinc supplementation above the recommended dietary allowance for the prevention of COVID-19, except in a clinical trial." As of March 2022, this guidance remained.

Doing something, like taking a supplement, to reduce our susceptibility to COVID-19 has a certain allure, conceded Dr. Celi. But should you count on zinc to protect you and your loved ones? "Based on what we know at present," said Dr. Celi, "nothing beats the use of masks and the avoidance of crowds."

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, and their local public health department as resources.