Supplements and COVID-19 Immunity: Separating Fact from Fiction

A group of various colorful supplement pills on a white background.
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Key Takeaways

  • Many people, media outlets, and even health experts have claimed that certain dietary supplements can boost immunity to COVID-19.
  • Online, it can seem like everyone is shouting “This supplement can save you from the coronavirus!” But, no studies prove any supplements to wholly protect people from COVID-19.
  • However, certain supplements are known to have immune-boosting properties, and in combination with good illness prevention practices, they might help you ward off viruses.

It probably feels like every time you log onto Facebook you get bombarded with ads from nutritional supplement companies claiming they’ve got the perfect prophylactic or antidote to COVID-19. These recommendations are probably also coming from your cousin who's into essential oils or maybe even your friend's nutritionist, but we're here to tell you that the jury is still out on all of these unverified medical claims.

Your body is a complex, unique thing performing countless functions at any given time—and no single supplement can catapult you to pristine health and put you in a position to completely ward off the novel coronavirus. The truth is, everyone is at risk for contracting COVID-19 regardless of their health status.

A healthy lifestyle complete with nutrient-dense meals (and supplementation where necessary) can certainly help your immune system function at an optimal level. But the science on particular supplements and COVID-19 just isn’t clear yet. Plus, most of the nutrients studied for their protective effects against COVID-19 “utilize doses too high to come solely from diet,” meaning the results may not play out in life as they do in the lab.

While some study results look promising, take it upon yourself to separate fact from hype before spending extra money on supplements.


Everyone needs vitamins to survive. Vitamin deficiencies can result in serious health complications, including rickets (vitamin D deficiency), blindness (vitamin A deficiency), and scurvy (vitamin C deficiency).

More commonly, vitamin deficiencies lead to unpleasant symptoms such as chronic fatigue, headaches, muscle weakness, disturbed sleep, and depression. Exact symptoms depend on what vitamin you’re deficient in. While it’s clear vitamins promote optimal health, they are not a cure-all for COVID-19. Here’s what you need to know about vitamins linked to boosted immunity. 

Vitamin C

Vitamin C is an important nutrient with many roles in the body. This vitamin is largely responsible for healthy skin and proper wound healing. It also happens to be a powerful antioxidant that helps combat inflammation and fight diseases.

The Claim

Because vitamin C has effects on the immune system, it may help boost immunity to COVID-19. 

Scientific Findings

We know vitamin C plays a role in immunity, but research on vitamin C in supplement form is conflicting. A Cochrane review of studies concluded that vitamin C supplementation does not reduce the incidence of common colds, although it might help you recover from a cold slightly faster.

The National Institutes of Health has, as of November 2020, determined that the role of vitamin C in fighting COVID-19 is unknown.

The Facts

More is not always better. Supplementing with vitamin C can help your overall health if you don’t get enough vitamin C through food. Too much vitamin C, however, can lead to stomach pain, nausea, and diarrhea. And an excess of vitamin C won’t help prevent COVID-19, so it’s not worth risking vitamin C toxicity. 

Vitamin D

Called the “sunshine vitamin” because your body makes it in the presence of sunlight, vitamin D serves a variety of functions—one being to keep your immune system humming along smoothly. 

The Claim

Vitamin D improves immune health because it actually activates your immune system to mount attacks. It also has anti-inflammatory properties. Together, these two functions make vitamin D a strong contender against the coronavirus.

Scientific Findings

Vitamin D is one of the most heavily researched vitamins. Plenty of research tells us that vitamin D is absolutely essential for optimal health, from your bones to your brain. We also know that vitamin D deficiency is linked to autoimmune diseases, respiratory diseases, and suppression of lung function, so it’s not far out to say vitamin D can help your immune system fight off COVID-19. 

Research on vitamin D and COVID-19 is ongoing, though, and it’s too soon to tell how vitamin D fights the novel coronavirus specifically.

The Facts

Though it’s clear that vitamin D plays an important role in immunity, supplementing with vitamin D will only help you if you’re deficient in vitamin D. If you already get enough vitamin D from the sun and through food to meet the recommended daily intake, you don’t need to supplement. 

Vitamin E

Vitamin E is a fat-soluble vitamin people must get through food or supplements. It’s a potent antioxidant known to modulate immune responses, and vitamin E deficiency can impair cellular immunity.

The Claim

Because of vitamin E’s known role in immunity, it could have a preventative role in the COVID-19 pandemic. 

Scientific Findings

Research on vitamin E and its protective effects against respiratory diseases is conflicting. For example, a study on nursing home residents with respiratory infections found that vitamin E supplementation was only effective for people with a certain genotype (set of genes). Furthermore, vitamin E supplementation may actually increase the risk of pneumonia in certain people who smoke. On the flip side, other reports suggest vitamin E can reduce oxidative damage associated with asthma, cancer, and other conditions.

The Facts

Adequate levels of vitamin E remain important for overall health and immunity, but more research is needed on vitamin E’s role specific to COVID-19. Plus, vitamin E is likely more effective when you get it from food rather than supplements.


Minerals, like vitamins, are essential to survival. Mineral deficiencies can lead to fatigue, poor appetite, muscle cramps, weakened immunity, and a range of other complications (like with vitamins, exact symptoms depend on the deficient mineral). Some minerals have immune-boosting properties—here’s what you should know about minerals linked to COVID-19 prevention. 


Magnesium helps regulate various bodily processes. In fact, this mineral is a cofactor to more than 300 enzymatic systems (AKA, without magnesium, your body can’t complete basic processes like muscle contraction, blood pressure regulation, or blood sugar control).

The Claim

Scientists and doctors have long known that magnesium is important for preventing diseases of the respiratory system, among other body systems. Plus, activation of vitamin D requires magnesium, which means inadequate magnesium could prevent your body from utilizing the ever-important vitamin D, even if you get enough vitamin D. 

Scientific Findings

A study published online in September 2020 found that a combined supplement of vitamin D, vitamin B12, and magnesium could reduce the severity of COVID-19 complications in older adults. An ongoing study from the University of Minnesota aims to find out if magnesium supplementation can prevent sudden cardiac death in COVID-19 patients. Because magnesium improves blood sugar control, supplements may help reduce the severity of complications in people with diabetes.

The Facts

Studies about magnesium and its protective effects against the novel coronavirus are ongoing. It’s too soon to tell if magnesium can boost your immunity to COVID-19 or reduce the severity of complications if you contract COVID-19.


Zinc is a systemically supportive mineral. It helps with cell growth and division, breakdown of carbohydrates, wound healing, the function of insulin, and even your senses of smell and taste. Zinc, unsurprisingly, also plays a role in immune health.

The Claim

Because zinc is known to support immunity and thought to fight common colds (ever had a zinc lozenge in the winter?), zinc has bubbled to the surface as a protective mineral against COVID-19.

Scientific Findings

Past studies have shown zinc to help fight off common colds, which are often caused by coronaviruses (but not the one that causes COVID-19). But other research complicates these findings. One systematic review found that only doses above 75mg a day shortened the duration of colds—no trial showed an effect for low doses of zinc.

Plus, it might be a matter of when you take zinc, not if: One meta-analysis determined that for zinc to work against a cold, the patient must take the supplement within 24 hours of the onset of symptoms.

Still, health experts think zinc has promise. A July 2020 study on zinc and COVID-19 suggests the mineral may protect against COVID-19 or lessen the severity of symptoms, while a “rapid review” (based on indirect evidence) also touts zinc as a potential preventative supplement in people who are deficient.

The Facts

Like every other nutrient, overconsumption of zinc probably won’t help to prevent COVID-19. Your body doesn’t need extra—it just needs enough. It’s wise to stay within the “tolerable upper intake level” (UL) for zinc, which indicates the highest level of consumption without known side effects.

Other Supplements

Aside from vitamins and minerals, your body also needs other nutrients to thrive. Antioxidants, for example, help your body fight off diseases. Here are the facts about a few supplements being studied in relation to COVID-19 immunity. 


Quercetin has acquired supernutrient status as the coronavirus pandemic pushes on. Quercetin, a pigment found in plants, is a type of flavonoid. Flavonoids provide a range of health benefits from antioxidant properties to anti-cancer properties.

The Claim

Quercetin’s powerful protective effects in the body show promise as an adjunct therapy in COVID-19 patients. 

Scientific Findings

A rapid review of studies on quercetin and respiratory infections determined that quercetin “may be an effective intervention to decrease the frequency and duration of respiratory tract infections.” However, the researchers go on to note that more studies are needed before quercetin can be recommended to treat COVID-19.

Another report concluded that quercetin has “theoretical, but significant, capability to interfere with SARS‐CoV‐2 replication,” again noting that more research is needed to confirm these effects.

The Facts

Quercetin certainly shows promise as a potential tool in the fight against COVID-19. However, quercetin is not a miracle drug. Scientists still don’t know exactly how quercetin functions in regard to the virus that causes COVID-19, and you should talk to your doctor before starting a supplement. 

Omega-3 Fatty Acids

Omega-3 fatty acids, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have a robust anti-inflammatory effect in the body. EPA and DHA come from foods like fish and shellfish.

The Claim

Because of their vigorous effect on immune cells, it’s possible that omega-3 fatty acids can help the body fight off COVID-19. 

Scientific Findings

Some research suggests that omega-3 fatty acid supplementation can help fight the “cytokine storm” induced by COVID-19. Cytokines are a group of signaling proteins that control the growth and activity of certain cells, including immune cells. The cytokine storm refers to “excessive production of pro-inflammatory cytokines” that leads to tissue damage and organ failure. Because omega-3 fatty acids have anti-inflammatory properties and an influence over immune cells, omega-3 supplements have potential as a preventative therapy.  

The Facts

It’s clear that omega-3 fatty acids influence the immune system. Consuming adequate omega-3 fatty acids through nutritious foods can improve your overall health and keep your immune system working properly. Like all the other nutrients covered here, excess omega-3 fatty acids can have a detrimental effect, and the effects of non-food supplementation on COVID-19 remains unknown. 

How to Actually Protect Yourself From COVID-19

Public health agencies such as the CDC and the WHO have established best practices for preventing COVID-19 infections. These guidelines are rooted in science and are known to slow and prevent the spread of infectious diseases like the novel coronavirus.

Here’s how to protect yourself from the novel coronavirus:

  • First, understand how COVID-19 spreads. This happens mainly through respiratory droplets, but the virus can also spread through aerosols (tiny airborne particles), direct contact (such as kissing), and contaminated surfaces.
  • Stay away from people who are sick whenever possible. If you’re a caretaker for someone who is sick, take extra precautions. 
  • Stay at least six feet away from people outside of your home. 
  • Wear a face covering that covers your mouth and nose when outside your home. Make sure to cover coughs and sneezes with cloth or tissues.
  • Wash your hands frequently. In the absence of soap and water, use a hand sanitizer with at least 60% denatured alcohol. 
  • Disinfect frequently touched surfaces, including light switches, doorknobs, your cell phone, and faucets, often.

Additionally, stay alert to your own health and the health of those in your household. If you notice any symptoms of COVID-19, call your doctor right away. Seek emergency medical care immediately if you have severe symptoms, such as difficulty breathing or chest pain.

What This Means for You

  • Navigating the constant influx of new coronavirus-related information is overwhelming. It’s important to use your best judgment when reading information online.
  • An overall healthy lifestyle can certainly help you fend off illnesses, including COVID-19, but everyone is susceptible to viral infections like the novel coronavirus, regardless of health status. 
  • It’s best to get vitamins, minerals, and other nutrients through a diet rich in whole foods to the fullest possible extent. This ensures variety and helps avoid toxicity from overconsumption of nutrients.
  • Implementing the proven best practices—like washing your hands frequently and staying away from people who are sick—into your daily life is the best way to prevent yourself from becoming sick with COVID-19.
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Article Sources
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  1. UC Davis Health. COVID-19 FAQS for health professionals. Updated November 16, 2020.

  2. Shakoor H, Feehan J, Al Dhaheri AS, et al. Immune-boosting role of vitamins D, C, E, zinc, selenium and omega-3 fatty acids: Could they help against COVID-19?Maturitas. 2021;143:1-9. doi:10.1016/j.maturitas.2020.08.003

  3. National Institutes of Health; Office of Dietary Supplements. Vitamin D: Fact Sheet for Health Professionals. Updated October 9, 2020.

  4. National Institutes of Health; Office of Dietary Supplements. Vitamin A: Fact Sheet for Health Professionals. Updated February 14, 2020.

  5. National Institutes of Health. Office of Dietary Supplements. Vitamin C: Fact Sheet for Health Professionals. Updated February 27, 2020.

  6. Carr AC, Maggini S. Vitamin C and immune functionNutrients. 2017;9(11):1211.doi:10.3390/nu9111211

  7. Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev. 2013;1:1465-1858. doi:10.1002/14651858.CD000980.pub4

  8. National Institutes of Health. COVID-19 treatment guidelines: adjunctive therapy: vitamin C. Updated November 3, 2020.

  9. Bivona G, Agnello L, Ciaccio M. The immunological implication of the new vitamin D metabolismCent Eur J Immunol. 2018;43(3):331-334. doi:10.5114/ceji.2018.80053

  10. Yin K, Agrawal DK. Vitamin D and inflammatory diseasesJ Inflamm Res. 2014;7:69-87. doi:10.2147/JIR.S63898

  11. Aranow C. Vitamin D and the immune systemJ Investig Med. 2011;59(6):881-886. doi:10.2310/JIM.0b013e31821b8755

  12. Hejazi ME, Modarresi-Ghazani F, Entezari-Maleki T. A review of vitamin D effects on common respiratory diseases: asthma, chronic obstructive pulmonary disease, and tuberculosisJ Res Pharm Pract. 2016;5(1):7-15. doi:10.4103/2279-042X.176542

  13. Zosky GR, Berry LJ, Elliot JG, James AL, Gorman S, Hart PH. Vitamin D deficiency causes deficits in lung function and alters lung structureAm J Respir Crit Care Med. 2011;183(10):1336-1343. doi:10.1164/rccm.201010-1596OC

  14. Biesalski HK. Vitamin D deficiency and co-morbidities in COVID-19 patients—A fatal relationship?NFS J. 2020;20:10-21. doi:10.1016/j.nfs.2020.06.001

  15. Taylor PN, Davies JS. A review of the growing risk of vitamin D toxicity from inappropriate practiceBr J Clin Pharmacol. 2018;84(6):1121-1127. doi:10.1111/bcp.13573

  16. National Institutes of Health; Office of Dietary Supplements. Vitamin E: Fact Sheet for Health Professionals. Updated July 31, 2020.

  17. Belisle SE, Hamer DH, Leka LS, et al. IL-2 and IL-10 gene polymorphisms are associated with respiratory tract infection and may modulate the effect of vitamin E on lower respiratory tract infections in elderly nursing home residents. Am J Clin Nutr. 2010;92(1):106-14. doi:10.3945/ajcn.2010.29207

  18. Hemilä H, Kaprio J. Vitamin E supplementation and pneumonia risk in males who initiated smoking at an early age: effect modification by body weight and dietary vitamin CNutr J. 2008;7:33. doi:10.1186/1475-2891-7-33

  19. Lee GY, Han SN. The role of vitamin E in immunity. Nutrients. 2018;10(11):1614. doi:10.3390/nu10111614

  20. National Institutes of Health; Office of Dietary Supplements. Magnesium: Fact Sheet for Health Professionals. Updated September 25, 2020.

  21. U.S. National Library of Medicine. Zinc in diet. Updated November 3, 2020.

  22. Tang C-F, Ding H, Jiao R-Q, Wu X-X, Kong L-D. Possibility of magnesium supplementation for supportive treatment in patients with COVID-19Eur J Pharmacol. 2020;886:173546. doi:10.1016/j.ejphar.2020.173546

  23. Cooper ID, Crofts CAP, DiNicolantonio JJ, et al. Relationships between hyperinsulinaemia, magnesium, vitamin D, thrombosis and COVID-19: rationale for clinical management. Open Heart. 2020;7:e001356. doi:10.1136/openhrt-2020-001356

  24. Tan CW, Ho LP, Kalimuddin S, et al. Cohort study to evaluate effect of vitamin D, magnesium, and vitamin B12 in combination on progression to severe outcomes in older patients with coronavirus (COVID-19). Nutrition. 2020;79-80:111017. doi:10.1016/j.nut.2020.111017

  25. O-Uchi J. Magnesium supplementation for preventing sudden cardiac death by COVID-19 viroporins in patients with pre-existing hypertension. University of Minnesota. 2020.

  26. Iotti S, Wolf F, Mazur A, Maier JA. The COVID-19 pandemic: Is there a role for magnesium? Hypotheses and perspectives. Magnes Res. 2020;33(2):21-27. doi:10.1684/mrh.2020.0465

  27. Hemilä H, Fitzgerald JT, Petrus EJ, Prasad A. Zinc acetate lozenges may improve the recovery rate of common cold patients: an individual patient data meta-analysisOpen Forum Infect Dis. 2017;4(2). doi:10.1093/ofid/ofx059

  28. Paules CI, Marston HD, Fauci AS. Coronavirus infections—more than just the common cold. JAMA. 2020;323(8):707-8. doi:10.1001/jama.2020.0757

  29. Hemiliä H. Zinc lozenges may shorten the duration of colds: a systematic review. Open Respir Med J. 2011;5:51-8. doi:10.2174/1874306401105010051

  30. Rao G, Rowland K. Zinc for the common cold—not if, but whenJ Fam Pract. 2011;60(11):669-671.

  31. Wessels I, Rolles B, Rink L. The potential impact of zinc supplementation on COVID-19 pathogenesis. Front Immunol. 2020;11:1712. doi:10.3389/fimmu.2020.01712

  32. Arentz S, Hunter J, Yang G, et al. Zinc for the prevention and treatment of SARS-CoV-2 and other acute viral respiratory infections: a rapid reviewAdv Integr Med. 2020;7(4):252-260. doi:10.1016/j.aimed.2020.07.009

  33. Anand David AV, Arulmoli R, Parasuraman S. Overviews of biological importance of quercetin: a bioactive flavonoidPharmacogn Rev. 2016;10(20):84-89. doi:10.4103/0973-7847.194044

  34. Aucoin M, Cooley K, Saunders PR, et al. The effect of quercetin on the prevention or treatment of COVID-19 and other respiratory tract infections in humans: a rapid reviewAdv Integr Med. 2020;7(4):247-251. doi:10.1016/j.aimed.2020.07.007

  35. Derosa G, Maffioli P, D’Angelo A, Pierro FD. A role for quercetin in coronavirus disease 2019 (COVID-19). Phytother Res. 2020;1-7. doi:10.1002/ptr.6887

  36. National Institutes of Health; Office of Dietary Supplements. Omega-3 Fatty Acids: Fact Sheet for Consumers. Updated October 1, 2020.

  37. Szabó Z, Marosvölgyi T, Szabó É, Bai P, Figler M, Verzár Z. The potential beneficial effect of EPA and DHA supplementation managing cytokine storm in coronavirus disease. Front Physiol. 2020;11:752. doi:10.3389/fphys.2020.00752

  38. Ragab D, Salah Eldin H, Taeimah M, Khattab R, Salem R. The COVID-19 cytokine storm; What we know so far. Front Immunol. 2020;11:1446. doi:10.3389/fimmu.2020.01446

  39. Fenton JI, Hord NG, Ghosh S, Gurzell EA. Immunomodulation by dietary long chain omega-3 fatty acids and the potential for adverse health outcomes. Prostaglandins, Leukot Essent Fatty Acids. 2013;89(6):379-390. doi:10.1016/j.plefa.2013.09.011 

  40. Centers for Disease Control and Prevention. Coronavirus disease 2019 (COVID-19)—prevention & treatment. Updated November 4, 2020.

  41. Centers for Disease Control and Prevention. Coronavirus disease 2019 (COVID-19)—What to do if you are sick. Updated September 11, 2020.