Can Supplements Fight Coronavirus (COVID-19)? 15 Immune Boosters

Vitamin D is a fat-soluble nutrient essential to the health and functioning of your immune system.

Vitamin D enhances the pathogen-fighting effects of monocytes and macrophages — white blood cells that are important parts of your immune defense — and decreases inflammation, which helps promote immune response.

Many people are deficient in this important vitamin, which may negatively affect immune function.

Vitamin D deficiency may be associated with an increased risk of several conditions, such as:

• osteoporosis
• some types of cancer
• type 2 diabetes
• cardiovascular disease
• depression

Research suggests that supplementing with vitamin D may help improve immune response.

For example, a 2019 review found that supplementing with vitamin D significantly decreased the risk of respiratory infections in people deficient in this vitamin and lowered infection risk in those with adequate vitamin D levels.

Vitamin D has also been researched in connection with COVID-19 because of its effect on the immune system. It may help expedite healing and stall inflammation in the respiratory system.

However, more research is needed to fully support its effects in the treatment of COVID-19.

The recommended daily intake of vitamin D is 15 micrograms (600 IU) for adults. However, it’s best to speak with a healthcare professional. They could help determine the best amount for you.

Supplements 101: Vitamin D

Zinc is a mineral commonly added to supplements and other healthcare products.

It’s essential for immune system function because it helps:

• immune cell development and communication
• reduce inflammation
• protect tissue barriers in the body
• prevent foreign pathogens from entering

Zinc deficiency may affect your immune system’s ability to function properly, resulting in an increased risk of infection and disease, including pneumonia.

Zinc deficiency affects around 2 billion people worldwide and up to 30% of older adults.

Research suggests that zinc supplements may be beneficial for people who are already sick. For example, it could help reduce the duration of the common cold.

Taking zinc long-term is typically safe for healthy adults, as long as the daily dose is under the set upper limit of 40 milligrams (mg) of elemental zinc per day.

Excessive doses may interfere with copper and iron absorption, which could increase your infection risk.

Vitamin C is perhaps the most popular supplement for protecting against infection due to its important role in immune health.

This vitamin supports the function of various immune cells and enhances their ability to protect against infection. It may also help:

• promote cellular death by clearing out old cells and replacing them with new ones
• function as an antioxidant and protect against oxidative stress
• reduce the duration and severity of upper respiratory tract infections, including the common cold

Additionally, high dose intravenous vitamin C treatment may help improve symptoms in people with severe infections, including sepsis and acute respiratory distress syndrome (ARDS) resulting from viral infections.

That said, more research is needed to fully support the role of vitamin C supplementation in this setting.

The upper limit for vitamin C is 2,000 mg. Supplemental daily doses are typically between 250 and 1,000 mg.

Black elderberry (Sambucus nigra), which has long been used to treat infections, is being researched for its effects on immune health.

Animal studies suggest elderberry extract may have antiviral potential against pathogens responsible for upper respiratory tract infections and strains of the influenza virus.

A 2018 review found that elderberry supplements may help reduce upper respiratory symptoms caused by viral infections. Similarly, a 2021 review noted that elderberry may help reduce the duration and severity of colds.

Some people recommend using elderberry supplements only in the early stages of COVID-19. However, no research has evaluated the use of elderberry for COVID-19.

Raw elderberries should be cooked before consumption. This helps destroy sambunigrin, a compound found in elderberries that may cause cyanide poisoning.

Speak with a healthcare professional before taking elderberry supplements.

Elderberry supplements are most often sold in liquid or capsule form.

Medicinal mushrooms have been used since ancient times to help prevent and treat infection and disease.

Research suggests that many types of medicinal mushrooms may help boost the immune system.

For example, a 2017 study in mice with tuberculosis found that treatment with cordyceps helped reduce bacterial load in the lungs, enhance immune response, and reduce inflammation.

Similarly, a 2019 study in 79 adults found that supplementing with 1.7 grams (g) of cordyceps mycelium culture extract led to a 38% increase in the activity of natural killer (NK) cells, a type of white blood cell that protects against infection.

Turkey tail is another medicinal mushroom that may enhance immune response, especially in people with certain types of cancer.

Medicinal mushroom products can be found in the form of tinctures, teas, and supplements.

A wide range of other supplements may help improve your immune system.

However, it’s important to note that more research is needed to support their full effects. Speak with a healthcare professional before taking any new supplements.

6. Astragalus

Astragalus is an herb commonly used in traditional Chinese medicine (TCM).

Animal research suggests its extract may significantly improve immune-related responses.

7. Selenium

Selenium is an essential mineral for immune health.

Animal research demonstrates that selenium supplements may enhance antiviral defense against influenza strains, including H1N1 and H9N2.

8. Garlic

Garlic has powerful anti-inflammatory, antiviral, and immunomodulating properties.

Research suggests it may help enhance immune health by stimulating and enhancing certain cytokines.

9. Andrographis

This herb contains andrographolide, a terpenoid compound that may have antiviral effects against several respiratory disease-causing viruses. It works by stimulating different types of cells, such as cytokine T cells and natural killer cells.

10. Licorice

Licorice contains many substances, including glycyrrhizin, that may help protect against viral infections.

Research suggests glycyrrhizin has several anti-inflammatory, anti-oxidative, and immune-boosting properties that could help protect against several illnesses, such as:

• hepatitis A, B, and C viruses
• vesicular stomatitis virus
• herpes simplex virus
• influenza A
• respiratory-syndrome–related coronavirus (SARS-CoV)
• respiratory syncytial virus
• vaccinia virus
• arboviruses

11. Pelargonium sidoides

Some human research supports the use of this African geranium extract to help alleviate symptoms of acute viral respiratory infections, including the common cold and bronchitis.

Still, results are mixed, and more research is needed.

12. B complex vitamins

B vitamins, including B12 and B6, are important for a healthy immune response.

Yet, many adults are deficient in them, which may negatively affect immune health.

13. Curcumin

Curcumin is the main active compound in turmeric. It has powerful anti-inflammatory properties, and animal studies indicate that it may help improve immune function.

14. Echinacea

Echinacea is a genus of plants in the daisy family.

Certain species have been shown to improve immune health and may protect against upper respiratory tract infections, though research is mixed.

15. Propolis

Propolis is a resin-like material honeybees produce for use as a sealant in hives.

Though it has impressive immune-enhancing effects and may have antiviral properties as well, more human research is needed.

What is the strongest immune system booster?

There’s no single, most powerful immune system booster. However, some foods, including bell peppers, fish, almonds, and citrus fruits, provide nutrients that may help strengthen your immune system.

What can I drink to boost my immune system?

Beverages, such as green tea, that contain antioxidants may help boost the immune system. But more research is needed.

Do any immune supplements actually work?

Research suggests that some supplements — like vitamin D, medicinal mushrooms, and elderberry — may help boost the immune system. However, more research is needed, and it’s important to speak with a healthcare professional before trying a new supplement.

Many supplements on the market may help improve immune health, such as zinc, elderberry, and vitamins C and D, among others.

Although these supplements may offer a small benefit for immune health, they can’t be used to replace a healthy diet and lifestyle.

If you decide you want to try a supplement, speak with a healthcare professional first, as some supplements may interact with certain medications or are inappropriate for some people.