The best supplements to boost immunity that are not vitamin C

Want to optimize your immune system to stay healthy or kick that cold a bit quicker? Getting enough vitamin C can help, but it isn’t the only immune-enhancer out there. Here are seven other best supplements to boost immunity you may also want to consider.

A strong immune system is key to preventing infection and disease. While getting enough




, and

eating nutritious foods

are essential for a healthy immune system, research shows specific vitamins, minerals, medicinal plants, and even beneficial bacteria can boost immune function and protect against illness. Vitamin C may be the most popular immune-boosting supplement on the market, but it’s certainly not the only one. 

So, what are the best supplements to boost immunity? Whether you want to level up your immunity or kick that cold a bit quicker, here are the best science-backed, immunity-enhancing supplements to consider that are not vitamin C.

Curious how else you can boost your immunity? Here are six more

unique, science-backed ways to enhance immune function


How to find the best supplements to boost immunity

With so many supplements on the market, it’s virtually impossible to decide which ones you should take, when you need to take them, and what you should take them with. So how do you sort through the noise and find the best supplements to boost immunity, improve sleep, enhance sports performance, and reduce stress? 

At Elo, we address these concerns and more by providing

personalized smart supplements

made just for you, based on

at-home blood testing



, and data from wearables. We also provide

1:1 dietitian support with our Elo Health coaches

so you can stay accountable, reach your goals, and better understand your health.

Get your personalized supplements started today!

Elo vitamin D supplement pack

Vitamin D

Vitamin D

has significant anti-inflammatory and antioxidant properties that play an essential role in immune function and support a healthy immune system [




]. Despite its importance, roughly half of the world’s population (and 90% of new Elo members) have inadequate vitamin D levels [



Vitamin D plays an important role in immune function, reducing inflammation and modulating growth and development. As such, low vitamin D levels can reduce immune function and have significant health consequences. 

For example, studies show vitamin D deficiency is associated with an increased risk of infection and higher rates of certain autoimmune diseases [




]. Early research also suggests having optimal vitamin D levels may lower your risk for COVID-19 infection and reduce its severity if you become infected [



Dosing recommendations

The Recommended Dietary Allowance (RDA) for people between the ages of 1 and 70 is 600 IU/day, and for adults over 70, the RDA is 800 IU/day [


]. However, a growing body of evidence has found these amounts are too low, particularly if you do not get adequate sun exposure, already have low levels, or have an increased risk for low vitamin D [









For most, a supplement providing 1,000–2,000 IU/day of vitamin D3 is sufficient to meet most people’s needs; however, individuals with moderate to severe deficiency may need a higher dose [



Woman holding probiotic drink


Studies show


, the good bacteria found in your gut and certain fermented foods, support immune health by inhibiting the growth and adhesion of harmful pathogens and enhancing specific immune cells' response [



In children, probiotic supplementation may reduce the risk of respiratory infections and may also shorten the duration of some viral respiratory illnesses [



In adults, studies indicate probiotics may enhance the body’s immune response to the flu shot. For example, in one trial, adults given probiotics or prebiotics showed significant improvements in protection against multiple strains, including H1N1, H3N2, and influenza B [



Probiotics (specifically Lactobacillus rhamnosus GR-1 and L. reuteri RC-14) may also bolster the body’s immune defenses against urinary tract infections (UTIs) in women [



The key to choosing the best probiotics to boost immunity is selecting the strain (or strains) that has been proven beneficial for your specific need and making sure your supplement contains an adequate amount of microorganisms. 

Not sure which probiotic you should take? Find out with Elo’s 1:1 dietitian support and

Smart Supplements


Dosing recommendations

Choosing a probiotic supplement can be challenging since strain type and dose size significantly affects whether a probiotic will have any benefit. The key to choosing the best probiotic for immune health is selecting the strain (or strains) that have been proven beneficial for this purpose. 

  • For flu-fighting benefits, Lactobacillus casei, L. paracasei, and Bifidobacterium longum seem to be the most effective of the strains studied.

  • For UTIs, Lactobacillus rhamnosus GR-1 and L. reuteri RC-14 seem effective.

  • A daily dose of 1 billion Lactobacillus GG may reduce the risk of respiratory infections in  children.

Many probiotic supplements contain 1 to 10 billion CFU per dose, whereas some products contain 50 billion or more. While it’s crucial your supplement contains enough live microbes to be effective, higher CFU counts do not necessarily produce greater health benefits [



shiitake mushrooms

Medicinal mushrooms

Medicinal mushrooms have incredible health benefits and can be a supportive sidekick for your immune system. Five fungi, in particular, have been shown to have the following immune-boosting benefits.

  • Reishi: Reishi mushrooms (Ganoderma lucidum) have long been used in Eastern medicine to promote health and longevity [


    ]. Studies show Reishi mushrooms may boost the immune system and even fight cancer [





  • Maitake: Maitake mushrooms have also been used in Eastern medicine to promote immune function for centuries. Research suggests these mighty mushrooms might play a role in healthy immune function and cancer prevention [





  • Turkey tail: Turkey tail mushrooms contain a potent compound called polysaccharide-K that gives this fungus its high antioxidant and anti-cancer properties. Research suggests it may also improve the immune system of those receiving chemotherapy [



  • Chaga: Studies show Chaga mushrooms are packed full of antioxidants that can help reduce oxidative stress and inflammation, which negatively affect the immune system [




    ]. Preliminary studies in mice suggest Chaga may also help prevent some forms of cancer, but more studies are needed to see if the benefits also apply to humans [





  • Shitake: Shitake mushrooms also appear to play a role in immunity.  One study found that people who consumed two dried shiitakes each day experienced a decrease in inflammation and an increase in immune markers [



For more on medicinal mushrooms, including how to take them to support a healthy immune system, check out

the ultimate guide to medicinal mushrooms


Dosing recommendations

When choosing medicinal mushroom supplements, in capsule or powder form, which you can add to teas, smoothies, or soup broth. 

Dosing recommendations vary widely between mushroom varieties, supplement forms, and brands. For this reason, it’s recommended you read supplement labels and follow dosing recommendations closely.



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

This unique berry extract has potent antibacterial and antiviral properties, particularly against pathogens responsible for upper respiratory infections. Studies have found it may be beneficial for treating respiratory infections, potentially shortening the duration and severity of colds and reducing respiratory symptoms [







Compared to oseltamivir (Tamiflu), elderberry may also be associated with a lower risk of influenza complications and adverse events [



Dosing recommendations

There is no standard dosing recommendation for elderberry. For immune benefits against the flu, some studies have found benefits with 4 tablespoons of elderberry extract syrup divided into four doses [



Elderberry supplements appear to be safe when used daily for up to 5 days; however, its long-term safety is unknown [



foods high in zinc


Zinc is a mineral that’s long been known to boost your immune system. It is essential in immune cell development, communication, and the body’s inflammatory response and also protects tissue barriers that prevent harmful pathogens from entering the body [



Like vitamin D, not getting enough zinc can significantly reduce immune function and increase the risk of infection and disease, including pneumonia [





Several studies also show zinc supplements may also protect against and reduce the duration of some respiratory tract infections like the common cold [







Dosing recommendations

Taking 5–10 mg/day of zinc appears adequate as a daily preventive. If you are at risk for, or have a zinc deficiency, a higher dosage of 25-45 mg/day might be necessary [



Zinc lozenges taken to reduce symptoms of the common cold appear to be most effective when the daily dose is over 75 mg and is divided over 6-8 doses, each separated by 2-3 hours. Because this dose is higher than the 40 mg Tolerable Upper Limit of zinc, prolonged intake of large amounts of zinc from supplements or lozenges is likely unsafe [



Garlic oil


Though it may get a bad rap for giving you stinky breath, garlic has powerful anti-inflammatory and antiviral properties that may also enhance immune function. 

Research shows this health-boosting bulb has antiviral, antifungal, and antibacterial properties and may also stimulate protective immune cells and help reduce the severity of cold and flu symptoms [





Dosing recommendations

Powdered garlic, aged garlic extract, and garlic oil are three common forms of garlic supplements. 

Research suggests aged garlic extract may offer the greatest health benefits. Studies looking at the immune benefits of aged garlic extract have found benefits at dosages ranging from 500 mg to 2,560 mg/day [



Garlic supplements can be toxic in very high amounts, so be sure not to exceed supplement dosage recommendations.

Turmeric in a black dish on a wooden table

Turmeric (Curcumin)

Best known for its anti-inflammatory effects,


can also help bolster immunity. 

Studies show curcumin, turmeric’s primary bioactive compound, can modulate the activation of key immune cells, including T cells, B cells, macrophages, neutrophils, natural killer cells, and dendritic cells. At low doses, curcumin can also enhance antibody response. [



Curcumin can also reduce the expression of various proinflammatory cytokines that are largely responsible for the development of chronic inflammation [




]. Chronic inflammation can impair normal immune function, increase susceptibility to infections and tumors, and even produce poor vaccine response in individuals; therefore, keeping inflammation at bay is critical to support immune health [



Dosing recommendations

Turmeric supplements are available in different dosages and contain varying amounts of curcumin. For instance, studies have shown that supplements that provide 500-1,500 mg of curcumin/day have been associated with numerous benefits related to inflammation and a healthy immune system [




Sleep, exercise, and a healthy diet are foundational to a healthy immune system. Still, significant research shows certain vitamins, minerals, medicinal plants, and even good bacteria can support immune health. From vitamin D and probiotics, to medicinal mushrooms, elderberry, zinc, garlic, and curcumin— our expert dietitians at Elo Health can help you determine which supplements might give you the biggest immune boost.

Disclaimer: The text, images, videos, and other media on this page are provided for informational purposes only and are not intended to treat, diagnose, or replace personalized medical care.

Key takeaways

  • Early studies have found having higher levels of vitamin D may lower the risk of COVID-19 infection and reduce its severity. 

  • Probiotics can support immune health by inhibiting the growth and adhesion of harmful pathogens and enhancing specific immune cells' response.

  • Several medicinal mushrooms and curcumin, the main bioactive in turmeric, have been shown to support immune function and possibly have anti-cancer benefits.

  • Elderberry extract, zinc, and garlic may help your immune system fight certain upper respiratory infections, including the common cold and flu.

  • Elo

    can help you optimize your immunity with

    personalized smart supplements

    and 1:1 dietitian support.


  1. Vitamin D. (2021, February 9). Mayo Clinic. Retrieved March 29, 2022, from

  2. Nair, R., & Maseeh, A. (2012). Vitamin D: The "sunshine" vitamin. Journal of pharmacology & pharmacotherapeutics, 3(2), 118–126.

  3. Siddiqee, M. H., Bhattacharjee, B., Siddiqi, U. R., & MeshbahurRahman, M. (2021). High prevalence of vitamin D deficiency among the South Asian adults: a systematic review and meta-analysis. BMC Public Health, 21(1).

  4. Demir, M., Demir, F., & Aygun, H. (2021). Vitamin D deficiency is associated with COVID-19 positivity and severity of the disease. Journal of medical virology, 93(5), 2992–2999.

  5. Yang, C. Y., Leung, P. S., Adamopoulos, I. E., & Gershwin, M. E. (2013). The implication of vitamin D and autoimmunity: a comprehensive review. Clinical reviews in allergy & immunology, 45(2), 217–226.

  6. Patel, K. (2022, March 28). Vitamin D. Examine.Com. Retrieved March 29, 2022, from

  7. Aloia, J. F., Patel, M., Dimaano, R., Li-Ng, M., Talwar, S. A., Mikhail, M., Pollack, S., & Yeh, J. K. (2008). Vitamin D intake to attain a desired serum 25-hydroxyvitamin D concentration. The American journal of clinical nutrition, 87(6), 1952–1958.

  8. Talwar, S. A., Aloia, J. F., Pollack, S., & Yeh, J. K. (2007). Dose response to vitamin D supplementation among postmenopausal African American women. The American journal of clinical nutrition, 86(6), 1657–1662.

  9. Ekwaru, J. P., Zwicker, J. D., Holick, M. F., Giovannucci, E., & Veugelers, P. J. (2014). The importance of body weight for the dose response relationship of oral vitamin D supplementation and serum 25-hydroxyvitamin D in healthy volunteers. PloS one, 9(11), e111265.

  10. Office of Dietary Supplements - Vitamin D. (2021, August 17). National Institutes of Health. Retrieved March 29, 2022, from

  11. Reid, G., Jass, J., Sebulsky, M. T., & McCormick, J. K. (2003). Potential uses of probiotics in clinical practice. Clinical microbiology reviews, 16(4), 658–672.

  12. Hojsak, I., Snovak, N., Abdović, S., Szajewska, H., Misak, Z., & Kolacek, S. (2010). Lactobacillus GG in the prevention of gastrointestinal and respiratory tract infections in children who attend day care centers: a randomized, double-blind, placebo-controlled trial. Clinical nutrition (Edinburgh, Scotland), 29(3), 312–316.

  13. Lei, W. T., Shih, P. C., Liu, S. J., Lin, C. Y., & Yeh, T. L. (2017). Effect of Probiotics and Prebiotics on Immune Response to Influenza Vaccination in Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients, 9(11), 1175.

  14. Falagas, M. E., Betsi, G. I., Tokas, T., & Athanasiou, S. (2006). Probiotics for prevention of recurrent urinary tract infections in women: a review of the evidence from microbiological and clinical studies. Drugs, 66(9), 1253–1261.

  15. Wachtel-Galor S, Yuen J, Buswell JA, et al. Ganoderma lucidum (Lingzhi or Reishi): A Medicinal Mushroom. In: Benzie IFF, Wachtel-Galor S, editors. Herbal Medicine: Biomolecular and Clinical Aspects. 2nd edition. Boca Raton (FL): CRC Press/Taylor & Francis; 2011. Chapter 9. Available from:

  16. Lin Z. B. (2005). Cellular and molecular mechanisms of immuno-modulation by Ganoderma lucidum. Journal of pharmacological sciences, 99(2), 144–153. 

  17. Sliva D. Ganoderma lucidum (Reishi) in cancer treatment. Integr Cancer Ther. 2003 Dec;2(4):358-64. doi: 10.1177/1534735403259066.

  18. Guggenheim, A. G., Wright, K. M., & Zwickey, H. L. (2014). Immune Modulation From Five Major Mushrooms: Application to Integrative Oncology. Integrative medicine (Encinitas, Calif.), 13(1), 32–44.

  19. Alonso, E. N., Orozco, M., Nieto, A. E., & Balogh, G. A. (2013). Genes related to suppression of malignant phenotype induced by Maitake D-fraction in breast cancer cells. Journal of Medicinal Food, 16(7), 602–617.

  20. Krestin. Krestin - an overview | ScienceDirect Topics. (n.d.). Retrieved May 26, 2022, from

  21. Najafzadeh, M., Reynolds, P. D., Baumgartner, A., Jerwood, D., & Anderson, D. (2007). Chaga mushroom extract inhibits oxidative DNA damage in lymphocytes of patients with inflammatory bowel disease. BioFactors (Oxford, England), 31(3-4), 191–200. 

  22. Javed, S., Mitchell, K., Sidsworth, D., Sellers, S. L., Reutens-Hernandez, J., Massicotte, H. B., Egger, K. N., Lee, C. H., & Payne, G. W. (2019). Inonotus obliquus attenuates histamine-induced microvascular inflammation. PloS one, 14(8), e0220776.

  23. Arata, S., Watanabe, J., Maeda, M., Yamamoto, M., Matsuhashi, H., Mochizuki, M., Kagami, N., Honda, K., & Inagaki, M. (2016). Continuous intake of the Chaga mushroom (Inonotus obliquus) aqueous extract suppresses cancer progression and maintains body temperature in mice. Heliyon, 2(5), e00111.

  24. Youn, M. J., Kim, J. K., Park, S. Y., Kim, Y., Kim, S. J., Lee, J. S., Chai, K. Y., Kim, H. J., Cui, M. X., So, H. S., Kim, K. Y., & Park, R. (2008). Chaga mushroom (Inonotus obliquus) induces G0/G1 arrest and apoptosis in human hepatoma HepG2 cells. World journal of gastroenterology, 14(4), 511–517.

  25. Dai, X., Stanilka, J. M., Rowe, C. A., Esteves, E. A., Nieves, C., Jr, Spaiser, S. J., Christman, M. C., Langkamp-Henken, B., & Percival, S. S. (2015). Consuming Lentinula edodes (Shiitake) Mushrooms Daily Improves Human Immunity: A Randomized Dietary Intervention in Healthy Young Adults. Journal of the American College of Nutrition, 34(6), 478–487.

  26. Krawitz, C., Mraheil, M. A., Stein, M., Imirzalioglu, C., Domann, E., Pleschka, S., & Hain, T. (2011). Inhibitory activity of a standardized elderberry liquid extract against clinically-relevant human respiratory bacterial pathogens and influenza A and B viruses. BMC complementary and alternative medicine, 11, 16.

  27. Frøkiær, H., Henningsen, L., Metzdorff, S. B., Weiss, G., Roller, M., Flanagan, J., Fromentin, E., & Ibarra, A. (2012). Astragalus root and elderberry fruit extracts enhance the IFN-β stimulatory effects of Lactobacillus acidophilus in murine-derived dendritic cells. PloS one, 7(10), e47878.

  28. Tiralongo, E., Wee, S. S., & Lea, R. A. (2016). Elderberry Supplementation Reduces Cold Duration and Symptoms in Air-Travellers: A Randomized, Double-Blind Placebo-Controlled Clinical Trial. Nutrients, 8(4), 182.

  29. Wieland, L. S., Piechotta, V., Feinberg, T., Ludeman, E., Hutton, B., Kanji, S., Seely, D., & Garritty, C. (2021). Elderberry for prevention and treatment of viral respiratory illnesses: a systematic review. BMC complementary medicine and therapies, 21(1), 112.

  30. Wessels, I., Maywald, M., & Rink, L. (2017). Zinc as a Gatekeeper of Immune Function. Nutrients, 9(12), 1286.

  31. Saper, R. B., & Rash, R. (2009). Zinc: an essential micronutrient. American family physician, 79(9), 768–772.

  32. Barnett, J. B., Hamer, D. H., & Meydani, S. N. (2010). Low zinc status: a new risk factor for pneumonia in the elderly?. Nutrition reviews, 68(1), 30–37.

  33. Prasad A. S. (2009). Zinc: role in immunity, oxidative stress and chronic inflammation. Current opinion in clinical nutrition and metabolic care, 12(6), 646–652.

  34. Martinez-Estevez, N. S., Alvarez-Guevara, A. N., & Rodriguez-Martinez, C. E. (2016). Effects of zinc supplementation in the prevention of respiratory tract infections and diarrheal disease in Colombian children: A 12-month randomised controlled trial. Allergologia et immunopathologia, 44(4), 368–375.

  35. Hemilä H. (2017). Zinc lozenges and the common cold: a meta-analysis comparing zinc acetate and zinc gluconate, and the role of zinc dosage. JRSM open, 8(5), 2054270417694291.

  36. Harris, J., S., C., S., P., & D., L. (2001). Antimicrobial properties of Allium sativum (garlic). Applied Microbiology and Biotechnology, 57(3), 282–286.

  37. Nantz, M. P., Rowe, C. A., Muller, C. E., Creasy, R. A., Stanilka, J. M., & Percival, S. S. (2012). 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, 31(3), 337–344.

  38. Jagetia, G. C., & Aggarwal, B. B. (2007). "Spicing up" of the immune system by curcumin. Journal of clinical immunology, 27(1), 19–35.

  39. (n.d.). Pro and anti-inflammatory cytokines in chronic inflammation.

  40. Furman, D., Campisi, J., Verdin, E., Carrera-Bastos, P., Targ, S., Franceschi, C., Ferrucci, L., Gilroy, D. W., Fasano, A., Miller, G. W., Miller, A. H., Mantovani, A., Weyand, C. M., Barzilai, N., Goronzy, J. J., Rando, T. A., Effros, R. B., Lucia, A., Kleinstreuer, N., & Slavich, G. M. (2019). Chronic inflammation in the etiology of disease across the life span. Nature Medicine, 25(12), 1822–1832.

  41. Patel, K. (2022a, March 18). Curcumin. Examine.Com. Retrieved April 28, 2022, from

  42. Office of Dietary Supplements - Probiotics. (2022, June 2). National Institutes of Health (NIH). Retrieved June 15, 2022, from

  43. Percival S. S. (2016). Aged Garlic Extract Modifies Human Immunity. The Journal of nutrition, 146(2), 433S–436S.

  44. Solomon, T., PhD & (2022, December 22). Garlic. Examine.

  45. Murray, M. R. & (2022, September 28). Zinc. Examine.

  46. Elderberries and Your Health. (2010, October 1). WebMD.