The 4 Best Supplements for COVID-19

Since the start of the COVID-19 pandemic, there have been dozens (if not hundreds) of claims for alternative remedies to prevent and treat the virus. Unfortunately this has led to a lot of misinformation about how to stay well, and it is hard to know what to take seriously. When it comes to preventing serious illness, “getting vaccinated and boosted is the best thing you can do to protect yourself. When fully vaccinated and boosted, you have a lesser chance of becoming sick or as severely ill,” says Paul Thottingal, MD, national infectious disease physician for Kaiser Permanente. 

It’s also important to keep up with CDC guidance and to follow additional precautions if you’re at increased risk for serious illness and complications. “To prevent illness, hand washing, social distancing, and mask-wearing are still important for those at increased risk of infection and in areas with increased community-level COVID-19 spread, even when mandates are relaxed,” adds Emily LaRose, DrPH, MS, RD, Nutrition and Global Health Consultant. 

In addition to vaccination, supporting your immune system with healthy habits may help you fight off illness more quickly if you are exposed. This includes “eating a varied diet with plenty of fruits and vegetables, getting enough sleep, regularly exercising, managing stress, not smoking, and avoiding alcohol,” says LaRose. 

Supplements do not replace a healthy diet, but certain supplements, especially vitamin and mineral supplements, may play a role in supporting a healthy immune system if you aren’t getting enough through food. If you’re considering a supplement to support your immune system, work closely with a healthcare provider to determine the best one for you. This is especially important if you have any underlying medical conditions or take prescription medications as many supplements can interact with medications or make illness worse.

Are Supplements Beneficial for Preventing or Treating COVID-19?

“There has been a lot of discussion about the role of dietary supplements in treating or preventing COVID-19. The CDC, National Institutes of Health (NIH), and Infectious DIsease Society of America have looked into whether they can help, and they all agree that there is currently no evidence to support that they do,” says Thottingal. 

That said, there is some evidence to suggest that supplements may be helpful for some people. 

• People with known nutrient deficiencies. It’s well established that vitamins A, C, and D as well as zinc, iron, and selenium play an important role in the immune system, and deficiencies can make you more susceptible to illness and less able to fight off illness quickly. Vitamin and mineral supplements can help close nutrient gaps to support your immune system.
• People with poor absorption. Those with poor nutrient absorption related to illness, especially those affecting the digestive tract, may benefit from supplements to achieve optimal nutrient status.
• People that restrict entire food groups or eat a very limited diet.  Avoiding entire food groups or eating a limited number of foods may put you at risk for nutrient deficiencies, in which case a supplement could help support a healthy immune system.

Who May Not Benefit from Supplements

• People who eat a well-balanced diet. “For most people with varied diets, vitamins, minerals, and other supplements are unlikely to provide any benefit or prevent COVID-19 infection,” says LaRose. One exception may be vitamin D as the primary source of this nutrient is sunshine and it’s not available in many foods. Because vitamin D deficiency is relatively common, even those that eat a well-balanced diet may benefit from supplementation.
• People taking certain medications. Many vitamin, mineral, and herbal supplements interact with medications and can reduce effectiveness or increase the amount the body absorbs, which can be dangerous. If you take any prescription or over-the-counter medications, check with a healthcare provider before starting a supplement.
• People with certain underlying conditions. While being immunocompromised may put you at higher risk for severe illness and complications from COVID-19, that doesn’t mean you should take supplements to prevent it. Some supplements can actually make conditions worse, so review any supplements you’re considering with a healthcare provider before starting one.

Supplements We Do Not Recommend at This Time

• Probiotics. Initial research suggests probiotics offer small benefits in very specific cases, but not enough is known to make a recommendation at this point. Probiotics are highly individualized and there are dozens of strains (with more being discovered regularly), and as of now we don’t know which—if any—specific strain may be helpful in preventing or treating COVID-19. In addition, probiotics can also make some digestive related conditions worse if you choose the wrong one. 
• Quercetin: Although some very small preliminary studies show promise that quercetin supplements may reduce severity of illness, these studies had several limitations. There is not enough evidence to support recommending quercetin supplements for preventing or treating COVID-19 right now. In addition, quercetin supplements may interact with common medications like antihistamines and cholesterol-lowering medications.
• Magnesium. Magnesium plays an indirect role in the immune system, so it has been discussed as a possible therapy for COVID-19. Currently the evidence to support magnesium supplementation is lacking. In fact, one study showed that both high and low magnesium levels were associated with COVID-19 hospitalization. This has been seen in hospitalizations unrelated to COVID-19, too. Therefore, until more research is done on the possible benefits of supplementation, it’s not recommended at this time.
• Selenium: Selenium plays an important role in the immune system. While preliminary data suggests a link between low selenium status and risk of severe disease, the quality of evidence is low and studies have been very small, so there’s not enough data to support supplementation. Since selenium deficiency is rare, there’s likely no benefit to adding a supplement.
• Vitamin E. Vitamin E plays an important role in immune function and may help lower inflammation. However, vitamin E deficiency is rare and there’s no research to support supplementation when you consume enough through food. 

Other supplements like echinacea, elderberry, ginseng, NAC, and melatonin have been discussed as possibly helpful in preventing or treating COVID-19, but there is currently no research to support these recommendations, and they are not essential for supporting immune health.

How We Select Supplements

Our team works hard to be transparent about why we recommend certain supplements; you can read more about our dietary supplement methodology here. 

We support supplements that are evidence-based and rooted in science. We value certain product attributes that we find to be associated with the highest quality products. We prioritize products that are third-party tested and certified by one of three independent, third party certifiers: USP, NSF, or ConsumerLab. 

It’s important to note that the FDA does not review dietary supplements for safety and effectiveness before they go to market. Our team of experts has created a detailed, science-backed methodology to choose the supplements we recommend.

What to Look for in COVID-19 Supplements

Third-Party Testing 

Supplements that are third-party tested are sent to a lab where they are tested to ensure they contain what they say they contain and are not contaminated with specific high-risk, common contaminants. However, it’s important to note:

• Third party testing does not test to see if a product is effective or safe for everyone, and it does not ensure the supplement will not interact with other supplements or medications.
• Not all third-party testing is created equal. It is not uncommon for supplement companies to pay labs for certificates after conducting minimal to no testing. 
• The third party certifications we can trust are: ConsumerLab, NSF, and USP. However, these certifications are difficult to obtain and/or expensive for manufacturers, so many companies choose not to get their products tested by one of these three organizations. 
• Sometimes products tested by these three companies are more expensive to try to offset the cost they pay for certification.
• Just because a supplement is not tested by one of these three companies, it does not mean it’s a bad product. We recommend doing some research on the reputability of the manufacturer, and calling up the manufacturer and their testing lab to determine their protocols and decide if you feel comfortable consuming the supplement.

Form 

Each vitamin or mineral supplement discussed in this article comes in more than one form. We’ve recommended a form that is supported by research, but there may be additional forms that are appropriate for you in some cases. Please discuss the best form of each supplement with a healthcare provider. 

Ingredients & Potential Interactions

It is essential to carefully read the ingredient list and nutrition facts panel of a supplement to know which ingredients and how much of each ingredient is included, relative to the recommended daily value of that ingredient. Please bring the supplement label to a healthcare provider to review the different ingredients contained in the supplement and any potential interactions between these ingredients and other supplements and medications you are taking.

Many of the supplements recommended above are available in combination with other nutrients, which may or may not be beneficial for you. In most cases, it’s best to choose a supplement that only contains the vitamin or mineral you are aiming to replenish, but there may be cases where combinations such as zinc and vitamin C or zinc with copper may be helpful. Please discuss the best option for you with a registered dietitian or a healthcare provider.

COVID-19 Supplement Dosage

Always speak with a healthcare professional before adding a supplement to your routine to ensure that the supplement is appropriate for your individual needs and to understand which dosage to take.

With the exception of omega-3 fatty acids,  each of the micronutrients recommended in this article (vitamin D, vitamin C, and zinc) have RDAs established by the National Institutes of Health Office of Dietary Supplements. The recommended dose for you will vary by nutrient and the amount that’s appropriate for you will depend on your diet, health status, and any medications you take. 

How Much is Too Much?

It’s important to ensure that you don’t exceed the upper limit as established by the National Institute of Health Office of Dietary Supplements. 

Your body filters and eliminates excess water-soluble vitamins like vitamin C, so it is difficult to over-consume these. However, fat-soluble vitamins like vitamin D can be stored in fat tissue and are dangerous when consumed in excess. Zinc can be damaging and lead to many negative side effects if consumed in excess.

You can help ensure that you are not exceeding micronutrient upper limits by running your multivitamin pick by a healthcare provider before you start taking it, sticking to a reputable brand, and getting annual blood work to make sure your micronutrient levels are within the normal range.