What Happens to Your Immune Health When You Take Vitamin C and Zinc Together?

As cold and flu season approaches, many people turn to supplements for immune system support. However, choosing supplements based on your specific health needs is essential rather than following general advice.

A food-first approach to nutrition is key. However, supplements may help fill gaps, especially during peak illness season. Some experts recommend Vitamin C and zinc as immune-boosting supplements.

What Science Says

Taking immune-boosting supplements is touted as a way to strengthen one's body’s ability to fight off an infection rather than avoid sickness altogether.

“No product to date has been scientifically proven to prevent an infection. At most, what can be reasonably expected from these products is shortened duration and/or severity of cold symptoms,” Sevak Olmessekian, PharmD, a pharmacist at UCLA Health, told Verywell.

Vitamin C and zinc are two science-backed supplements that may help boost your immune system.

“Some studies have found that taking vitamin C before the start of cold symptoms, in other words prophylactically, may shorten how long the symptoms last,” Olmessekian said. Similarly, "some studies have suggested that zinc could reduce the duration of common cold symptoms but has little effect on preventing a cold," he added.

Benefits of Vitamin C

Vitamin C is a potent antioxidant with the following properties:

• Neutralizes free radicals in your body
• Reduces oxidative stress
• Bolsters your immune system
• Speeds up healing
• May lower chronic disease risk (ex., cancer, heart disease)¹²

As mentioned, research suggests vitamin C supplements may reduce the duration and severity of cold symptoms in specific groups of people.³ However, more research is needed.

Benefits of Zinc

Zinc is also a powerful antioxidant and has the following effects:

• Helps immune cell production
• Improves deficiency in sickle-cell disease⁴
• May help prevent chronic diseases⁵⁶
• May increase blood sugar control in people with diabetes⁷
• May improve skin health⁸

Supplementing with zinc may help your immune system and reduce specific inflammatory markers. This is especially true if you are deficient in zinc.

Benefits of Taking Them Together

Taking vitamin C and zinc together may theoretically further bolster your immune system. However, the evidence is mixed.⁹

Evaluate your current intake to understand any potential nutritional gaps:¹⁰

• Vitamin C: Adults need between 75 and 90 milligrams (mg) of vitamin C daily.¹ Taking more than 2,000 mg a day may cause side effects.
• Zinc: Adults need between 8 and 11 mg of zinc daily.¹¹ Taking more than 40 mg a day may cause severe side effects.

Specific populations may experience a higher risk of deficiency and benefit from supplementation:

• Older adults
• People who smoke
• People with substance use disorders
• Individuals with limited food intake
• Those with absorption issues (e.g., gastrointestinal disorders)^1,11

Speak with your healthcare provider if you have concerns and whether you may benefit from taking vitamin C and zinc together.

Other Immune Boosting Supplements

• Vitamin D is another supplement that supports immune system function. Nearly half of the world’s population has vitamin D insufficiency.¹² Those who don’t get enough of it may benefit from a supplement during cold and flu season, according to van der Merwe.
• Vitamin E may also play a role in keeping the immune system regulated, though you don’t necessarily need to take a supplement for it. It can be found in nuts, vegetable oils, seeds, green leafy vegetables, and fortified cereals, among other foods.¹³
• Echinacea is another common cold remedy, though the evidence is mixed on whether it may work.^14,15

Firdaus A, Yunus MH, Izhar SK, Afaq U. Medicinal Plants in the Treatment of Respiratory Diseases and their Future Aspects. Recent Pat Biotechnol. 2025;19(1):2-18. doi:10.2174/0118722083278561231212072408

What This Means For You

If you’re considering immune-boosting supplements, focus on specific nutrients like vitamin C, zinc, and vitamin D, which have some scientific backing. However, additional supplements might not be necessary for most people with a balanced diet.

Sources:

1. National Institutes of Health Office of Dietary Supplements. Vitamin C.
2. Forman HJ, Zhang H. Targeting oxidative stress in disease: promise and limitations of antioxidant therapy. Nat Rev Drug Discov. 2021;20(9):689-709. doi:10.1038/s41573-021-00233-1
3. Hemilä H, Chalker E. Vitamin C reduces the severity of common colds: A meta-analysis. BMC Public Health. 2023;23(1):2468. doi:10.1186/s12889-023-17229-8
4. Miranda CTOF, Vermeulen-Serpa KM, Pedro ACC, et al. Zinc in sickle cell disease: A narrative review. Journal of Trace Elements in Medicine and Biology. 2022;72. doi:10.1016/j.jtemb.2022.126980
5. Olechnowicz J, Tinkov A, Skalny A, Suliburska J. Zinc status is associated with inflammation, oxidative stress, lipid, and glucose metabolism. J Physiol Sci. 2018;68(1):19-31. doi:10.1007/s12576-017-0571-7
6. Mousavi SM, Hajishafiee M, Clark CCT, et al. Clinical effectiveness of zinc supplementation on the biomarkers of oxidative stress: A systematic review and meta-analysis of randomized controlled trials. Pharmacol Res. 2020;161:105166. doi:10.1016/j.phrs.2020.105166
7. Wang X, Wu W, Zheng W, et al. Zinc supplementation improves glycemic control for diabetes prevention and management: A systematic review and meta-analysis of randomized controlled trials. Am J Clin Nutr. 2019;110(1):76-90. doi:10.1093/ajcn/nqz041
8. Yee BE, Richards P, Sui JY, Marsch AF. Serum zinc levels and efficacy of zinc treatment in acne vulgaris: A systematic review and meta-analysis. Dermatologic Therapy. 2020;33(6). doi:10.1111/dth.14252
9. Hemilä H, Chalker E. Vitamin C and zinc lozenges for COVID-19?. J Am Pharm Assoc (2003). 2021;61(5):e39. doi:10.1016/j.japh.2021.05.018
10. Siripornpanich S, Chongviriyaphan N, Manuyakorn W, Matangkasombut P. Zinc and vitamin C deficiencies associate with poor pulmonary function in children with persistent asthma. Asian Pac J Allergy Immunol. 2022;40(2):103-110. doi:10.12932/AP-100620-0878
11. National Institutes of Health Office of Dietary Supplements. Zinc.
12. Sizar O, Khare S, Goyal A, Givler A. Vitamin d deficiency. In: StatPearls. StatPearls Publishing; 2024.
13. National Institutes of Health (NIH). Vitamin E Fact Sheet for Health Professionals.
14. DeGeorge KC, Ring DJ, Dalrymple SN. Treatment of the common cold. Am Fam Physician. 2019;100(5):281-289.
15. Firdaus A, Yunus MH, Izhar SK, Afaq U. Medicinal Plants in the Treatment of Respiratory Diseases and their Future Aspects. Recent Pat Biotechnol. 2025;19(1):2-18. doi:10.2174/0118722083278561231212072408

Important Notice: This article was originally published at www.verywellhealth.com  by Maggie O'Neill where all credits are due. Fact checked by Nick Blackmer

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