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6 Best Vitamins and Supplements for Respiratory Infections: Improve Your Immunity

Discover supplements and vitamins that may improve your immunity. Learn more about the best supplements for staying healthy.

Diana Licalzi
By Diana Licalzi
a woman is holding a small house in her hand
Edited by Ivana Markovic

Updated May 29, 2024.

a cup of tea with lemon, ginger, ginger, and mint

At InsideTracker, we strive to provide you with science-based guidance and the essential truths about your blood and genetic biomarkers. We noticed an influx of misinformation about immunity and respiratory infections and want to clarify it.

Respiratory infections affect the sinuses, throat, airways, or lungs and include a range of illnesses, from pneumonia to the common cold. Your immune system is a complicated network of cells, tissues, and organs that work together to protect your body from them.

Research shows that certain supplements may reduce your risk of infection and the severity of your symptoms. Below, we'll explain and recommend those that are scientifically proven remedies that may safely support your immune system.

Key takeaways

  • Certain foods and supplements can help reduce your risk of infection and lessen the severity of symptoms. Probiotics, zinc, vitamin C, vitamin D, ginseng, and garlic can be effective.
  • It's important to get the right amount of nutrients. Too little or too much can have negative consequences. For example, high doses of vitamin C can cause stomach upset and diarrhea.
  • More research is needed on some popular supplements like elderberry and echinacea. While some studies have shown positive results, others have been inconclusive.

Our 6 best vitamins and supplements for respiratory infection

1. Fermented foods and probiotics

Your gut has many healthy microbes that compete against invading pathogens. They also digest nutrients like fiber and other carbohydrates via fermentation. The process results in byproducts that play many vital roles in the body, from protecting the colon to improving insulin sensitivity.

Probiotic supplements and fermented foods are sources of live microbes. They can significantly reduce the risk of infection by fighting pathogens in the gut and contributing to anti-inflammatory pathways around the body. 

Some strains better protect against inflammation and infection, particularly in the upper respiratory tract. [1–4] They are:

  • Lactobacillus plantarum
  • Bifidobacterium lactis
  • Lactobacillus casei
  • Lactobacillus rhamnosus (also known as Lactobacillus GG)

If you’re considering taking a probiotic supplement, look for one that lists two or more of the above strains. Bottles that acknowledge immunity or inflammation on the label are the ones likely to contain them, but always take the time to look at the ingredient list.

Your diet is also an essential tool for nurturing a healthy microbiome. Fermented foods like kefir and kimchi can directly plant healthy microbes in your gut, and foods rich in fiber, like beans and cruciferous vegetables, help them to thrive once they’ve found their home.

» Discover how InsideTracker nurtures your gut microbiome

2. Zinc

Zinc is involved in your body's cell-mediated and humoral immune responses, each generated for a particular pathogen. Low levels of it can affect your system's ability to fight off infections.

After examining 13 randomized placebo-controlled studies, researchers found that taking zinc within 24 hours of the first signs of a cold may shorten its duration and reduce the symptoms. [5]

You can find it in red meats, oysters, mollusks, and whole grains. Legumes also have it, but in lower quantities and with less absorption compared to animal products. Vegetarians and the elderly are especially at risk for insufficient zinc if they rely on diet alone.

Both men and women need 11mg and 8mg of zinc daily. 

While it is essential to meet your needs, you should avoid going overboard. The maximum amount of zinc you should have in a day is 40mg, according to the Food and Nutrition Board. Intakes above 40mg can cause copper deficiency and neurological problems. [6,20] 

When taking supplements and zinc-based cold remedies, be sure to check the amount, as some of them have levels above the upper limit. On the other hand, if you have trouble meeting your daily zinc needs or if you feel the signs of a cold coming on, take 25mg of zinc per day.

Note: Most supplements come in 50 mg doses, so split the dosage in two before taking it. It's also best that you take zinc supplements on an empty stomach.

3. Vitamin C

We can't talk about immunity without addressing vitamin C, an essential micronutrient that we should get from our diets. It acts as an antioxidant, enhancing immune cell function and supporting anti-inflammatory pathways in the body.

A review by the Department of Pathology from the University of Otago in New Zealand examined hundreds of studies on vitamin C's role in improving respiratory immunity. The researchers concluded that taking 100–200mg of daily vitamin C may prevent respiratory infections. []

They also found that a typical Airborne packet or supplement has around 1,000 mg. What's more, the absorption of vitamin C decreases with increased intake. For example, we soak up only 16% at high intakes (~1,200mg) but up to 98% at low (<20mg).

Once you hit 1,000mg, you absorb less than 50% of the vitamin C you consume—the rest you'll excrete through urine. [20]

The toxicity of vitamin C is unusual, but chances for long-term adverse effects may increase if you supplement above the tolerable upper intake level of 2,000mg daily.[7]

It's also most abundant in fresh, whole foods like pineapple, kiwi, and broccoli sprouts. Since it's a water-soluble vitamin, the body never stores it. That's why we must focus on eating properly every day. 

Note: The lack of them in the typical US diet caused Vitamin C to be one of the leading nutrient deficiencies in the country. [19]

» Find out why we need vitamins C and E

4. Vitamin D

In a systematic review of randomized control trials, researchers concluded that vitamin D supplementation protects individuals from acute respiratory tract infections, like the common cold. The effect was especially apparent in people who started with a deficiency. [8]

Additionally, they found that as people's serum levels of vitamin D dropped, the chances of infection increased. [9] InsideTracker recommends that your levels remain above 32 ng/mL for optimal health.

Note: Optimal vitamin D levels may improve respiratory immunity against infections. Aim for an intake of 1,000 IU of vitamin D daily.

A woman running to improve her respiratory immunity.

5. Ginseng

Ginseng is a root available in supplement form that reduces inflammation and supports immunity. Multiple studies have shown its positive effects on the common cold and respiratory tract infections.

In a systematic review, researchers concluded that its extract reduced the duration of the common cold. [10] A double-blind, randomized control trial replicated the same results over four months. [11]

Note: Ginseng also improves respiratory immunity and reduces the length of infection symptoms in an elderly population by 48 and 55%, respectively. [12] It's most effective when taken within a two-hour window of a meal. You should aim for 2,000mg daily.

» Discover how beans might reduce your inflammation and more

6. Garlic

Many cultures throughout history used garlic to fight infectious diseases as it has antimicrobial, antifungal, and antiviral properties. [13] Modern studies show that including it in your diet may actually activate immunity genes and reduce the severity and incidence of a cold.

In a double-blind, randomized control trial, subjects took a garlic supplement or a placebo over 12 weeks between November and February. The treatment group had fewer colds and recovered quicker compared to the placebo. [14]

In a similar study, after 45 days of supplementing, participants' NK and T-cells significantly improved function compared to the placebo group. Both of them are involved in immune function. After 90 days, participants had fewer sick days and incidences of colds compared to the placebo group. [15]

Lastly, another study found that adding raw garlic to meals helped to activate genes related to immunity.[16] 

Note: You can add a raw garlic clove to your meals or supplement with two 500mg doses, one pill after breakfast and the other after dinner. 

A poster showing garlic benefits for respiratory immunity.

» Check out the symptoms that mean you should skip your workout

Research is still out on elderberry and echinacea

Elderberry syrup has recently entered the spotlight as a natural way to support the immune system. The flowers and berries of this plant have been used in teas, syrups, and gummies.

To date, researchers have conducted only a handful of small-scale studies on its effects on immunity. While the outcomes were positive, the quantities used differed by study. [17]

For example, one had participants take 300mg of elderberry extract while another provided 60 mL of syrup for five straight days. To put it into perspective, sambucol, one of the most popular commercially available elderberry syrups, has 3.8mg of elderberry for one recommended serving (10mL) and a whopping 8g of sugar.

Even when taken four times a day, as suggested for intensive use purposes, it still wouldn't reach clinically tested levels. Plus, it provides roughly the amount of sugar in two Hershey's bars.

» Explore how blood sugar changes your body and brain

What about echinacea?

When it comes to echinacea. In a meta-analysis examining 24 randomized controlled trials, researchers concluded that its products don't provide benefits for treating colds.

Additionally, a study made headlines in 2003 when researchers tested 59 different echinacea supplements available on the market. They found that only 52% met the quantities of echinacea listed on the supplement label, and 10% contained none of it at all. [18]

Given the lack of studies examining elderberry and the inconclusive results for echinacea, we don't recommend taking either to treat colds or to support immune function at this time.

» Discover more tips for taking supplements

Unlock your body's defense system

Studies show certain daily supplements and vitamins may reduce infection risk, duration, and symptom severity for colds, flu, and upper respiratory infections. Each offers unique immune support.

Remember, the supplement industry is unregulated. Choose reputable, science-backed products and consult your physician before starting.

While these vitamins and supplements offer immune benefits, an InsideTracker biomarker analysis can provide deeper insights. It reveals areas of your health where you're optimized and where you need to improve. You'll get science-backed recommendations that align with your goals so you can live healthier, longer.

Disclaimer: InsideTracker doesn't diagnose or treat medical conditions. Consult your physician for any health concerns.


[1] E. Guillemard, F. Tondu, F. Lacoin, and J. Schrezenmeir, “Consumption of a fermented dairy product containing the probioticLactobacillus caseiDN-114 001 reduces the duration of respiratory infections in the elderly in a randomised controlled trial,” British Journal of Nutrition, vol. 103, no. 1, pp. 58–68, Sep. 2009, doi: 10.1017/s0007114509991395. Available:

[2] A. Berggren, I. L. Ahrén, N. Larsson, and G. Önning, “Randomised, double-blind and placebo-controlled study using new probiotic lactobacilli for strengthening the body immune defence against viral infections,” European Journal of Nutrition, vol. 50, no. 3, pp. 203–210, Aug. 2010, doi: 10.1007/s00394-010-0127-6. Available:

[3] T. J. Smith, D. Rigassio-Radler, R. Denmark, T. Haley, and R. Touger-Decker, “Effect of Lactobacillus rhamnosus LGG® and Bifidobacterium animalis ssp. lactis BB-12® on health-related quality of life in college students affected by upper respiratory infections,” British Journal of Nutrition, vol. 109, no. 11, pp. 1999–2007, Oct. 2012, doi: 10.1017/s0007114512004138. Available:

[4] Q. Hao, B. R. Dong, and T. Wu, “Probiotics for preventing acute upper respiratory tract infections,” Cochrane Library, Feb. 2015, doi: 10.1002/14651858.cd006895.pub3. Available:

[5] “PURLs: Zinc for the common cold--not if, but when,” PubMed, Nov. 01, 2011. Available:

[6] “Office of Dietary Supplements - Zinc.” Available:

[7] “Office of Dietary Supplements - Vitamin C.” Available:

[8] A. R. Martineau et al., “Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data,” BMJ. British Medical Journal, p. i6583, Feb. 2017, doi: 10.1136/bmj.i6583. Available:

[9] A. A. Ginde, J. M. Mansbach, and C. A. Camargo, “Association between serum 25-Hydroxyvitamin D level and upper respiratory tract infection in the third National Health and Nutrition Examination Survey,” Archives of Internal Medicine, vol. 169, no. 4, p. 384, Feb. 2009, doi: 10.1001/archinternmed.2008.560. Available:

[10] J. K. Seida, T. Durec, and S. Kuhle, “North American(Panax quinquefolius)and Asian Ginseng(Panax ginseng)Preparations for Prevention of the Common Cold in Healthy Adults: A Systematic Review,” Evidence-based Complementary and Alternative Medicine, vol. 2011, pp. 1–7, Jan. 2011, doi: 10.1093/ecam/nep068. Available:

[11] G. N. Predy, “Efficacy of an extract of North American ginseng containing poly-furanosyl-pyranosyl-saccharides for preventing upper respiratory tract infections: a randomized controlled trial,” CMAJ. Canadian Medical Association Journal, vol. 173, no. 9, pp. 1043–1048, Oct. 2005, doi: 10.1503/cmaj.1041470. Available:

[12] J. E. McElhaney, V. Goel, B. Toane, J. Hooten, and J. J. Shan, “Efficacy of COLD-FX in the prevention of Respiratory Symptoms in Community-Dwelling Adults: a Randomized, Double-Blinded, Placebo Controlled trial,” ˜the œJournal of Alternative and Complementary Medicine/Journal of Alternative and Complementary Medicine, vol. 12, no. 2, pp. 153–157, Mar. 2006, doi: 10.1089/acm.2006.12.153. Available:

[13] “Garlic: a review of potential therapeutic effects,” PubMed, Jan. 01, 2014. Available:

[14] P. Josling, “Preventing the common cold with a garlic supplement: A double-blind, placebo-controlled survey,” Advances in Therapy, vol. 18, no. 4, pp. 189–193, Jul. 2001, doi: 10.1007/bf02850113. Available:

[15] M. P. Nantz, C. A. Rowe, C. E. Muller, R. A. Creasy, J. M. Stanilka, and S. S. Percival, “Supplementation with aged garlic extract improves both NK and γδ-T cell function and reduces the severity of cold and flu symptoms: A randomized, double-blind, placebo-controlled nutrition intervention,” Clinical Nutrition, vol. 31, no. 3, pp. 337–344, Jun. 2012, doi: 10.1016/j.clnu.2011.11.019. Available:

[16] C. S. Charron et al., “A single meal containing raw, crushed garlic influences expression of immunity- and Cancer-Related genes in whole blood of humans,” ˜the œJournal of Nutrition/˜the œJournal of Nutrition, vol. 145, no. 11, pp. 2448–2455, Nov. 2015, doi: 10.3945/jn.115.215392. Available:

[17] J. Hawkins, C. Baker, L. Cherry, and E. Dunne, “Black elderberry (Sambucus nigra) supplementation effectively treats upper respiratory symptoms: A meta-analysis of randomized, controlled clinical trials,” Complementary Therapies in Medicine, vol. 42, pp. 361–365, Feb. 2019, doi: 10.1016/j.ctim.2018.12.004. Available:

[18] C. M. Gilroy, J. F. Steiner, T. Byers, H. Shapiro, and W. Georgian, “Echinacea and truth in labeling,” Archives of Internal Medicine, vol. 163, no. 6, p. 699, Mar. 2003, doi: 10.1001/archinte.163.6.699. Available:

[19] A. Carr and S. Maggini, “Vitamin C and immune function,” Nutrients, vol. 9, no. 11, p. 1211, Nov. 2017, doi: 10.3390/nu9111211. Available:

[20] Groff. Advanced Nutrition and Human Metabolism. Australia: Wadsworth/Cengage Learning, 2009. Print.