What Happens When You Take Vitamin C to Ease Your Cold Symptoms

Table of ContentsView AllTable of ContentsDoes Vitamin C Help Prevent or Treat Colds?What Is Vitamin C?How Much Vitamin C Do I Need?Who Needs More?Sources of Vitamin CNatural Sources of Vitamin CIs It Safe for Me?Alternatives

Table of ContentsView All

View All

Table of Contents

Does Vitamin C Help Prevent or Treat Colds?

What Is Vitamin C?

How Much Vitamin C Do I Need?

Who Needs More?

Sources of Vitamin C

Natural Sources of Vitamin C

Is It Safe for Me?

Alternatives

One such remedy, vitamin C, is widely known for its antioxidant properties and its role in supporting your immune system.However, the question of whether vitamin C helps with colds remains.

Vitamin C supplements may help totreatcolds. However, it is unclear whether they can prevent colds. Vitamin C deficiency generally decreases immune function and increases your risk of infections.

Based on a group of studies,vitamin Csupplementationmay have helped prevent the common coldin the following groups of people:

Vitamin C levels may decrease during common cold episodes, suggesting thatyour body uses vitamin C during common cold infections. Furthermore, in clinical study, giving vitamin C during a common cold episode improved the decline of vitamin C levels.This suggests vitamin Cmay help you recover.

While vitamin C may shorten the duration and intensity of colds, the optimal dosage is unknown. However, clinical research has suggested1 to 4 grams per day (g/day)ofvitamin Cforfive daysdemonstrated effectiveness.

However, it’s important to note that the tolerableupper limit(UL) of vitamin C for adults is2,000 milligrams (mg) per day. For children1-3 years, the vitamin C UL is400 mg; for4-8years,650 mg; for9-13years,1,200 mg; and14-18years,1,800 mg. Avoid exceeding this amount unless under the guidance of your or your child’s healthcare provider.

Vitamin C, also known asascorbic acid, is a water-soluble vitamin found in a variety of fruits and vegetables, includingcitrus fruits,strawberries,bell peppers, andbroccoli. Its functions include the following:

Vitamin Csupplementsare usually in the form of ascorbic acid, but also come in other forms, including the following:

Little evidence indicates which form of vitamin C is better than the other.Your best choice may depend on your individual preferences or needs.

Several factors can contribute to not getting enough vitamin C, making it difficult for some individuals to meet the recommended dietary levels. These factors include the following:

Excessivephysicalorpsychological stressalsoincreasesvitamin C requirements.

Understanding the recommended daily intake, which varies based on age and other factors, is vital to help ensure you get enough vitamin C. The table below lists the average recommended dietary allowances (RDAs) of vitamin C based on different ages.

Individuals Who May Need More Vitamin C

Specific factors and conditions can increase the body’s need for vitamin C. These include lifestyle habits, medical conditions, and specific life stages. Here’s a breakdown of some groups that may require higher vitamin C intake:

In adults, thedaily upper limit for vitamin Cintake from all sources, including food, beverages, and supplements,is 2,000 mg.Anything above this has the potential to cause adverse effects, particularly after more than five days.

Since humans cannot produce vitamin C, it must be obtained from diet or supplements.Fruits and vegetablesare rich sources of vitamin C, in addition to other vital nutrients.

Obtaining vitamin C from food sources is especially beneficial as these foods provide additional helpful nutrients, including vitamins, minerals, and fiber. Natural sources of vitamin C include, but aren’t limited to, the following fruits and vegetables:

Is Vitamin C Safe for Me?

Before adding vitamin C supplements to your routine, it’s essential to understand the potential risks, recommended dosages, and precautions, especially for people with specific health conditions.

High Dosages

Allergies

If you obtain vitamin C from supplements and are allergic to certain ingredients, pay close attention to the inactive ingredients contained in the supplements. You may wish to avoid specific vitamin-C-rich fruits and vegetables if you are allergic to them.

Precautions

Use vitamin C cautiously if you have the following conditions:

Always consult with your healthcare provider before starting a supplement, especially if you have, or at risk for, underlying health conditions.

Interactions

Vitamin C may interact with specific treatments or medications, including the following:

This is not a complete list of interactions that may occur with vitamin C. Speak to your healthcare provider and pharmacist before starting vitamin C supplementation or adjusting your intake, and let them know what you take. This includes prescription and over-the-counter medications, vitamins, and herbal supplements.

Side Effects

While Vitamin C offers numerous health benefits, it’s essential to be aware of the following potential side effects, particularly when taking high doses:

Always consult with your healthcare provider before starting supplementation, especially if you have underlying health conditions or are at risk for kidney stones.

Alternatives for Cold Prevention

In addition to vitamin C, several other measures can help prevent the common cold:

By incorporating these lifestyle habits—staying hydrated, eating immune-boosting foods, getting sufficient sleep, and managing stress, you can help strengthen your immune system and hopefully reduce the likelihood of catching a cold.

Summary

Known for its immune-boosting property, vitamin C has been shown to shorten the duration of the common cold and reduce the severity of its symptoms. Vitamin C may prevent the common cold only in a particular population group. The use of vitamin C after the onset of the common cold for treatment is unclear.

Though vitamin  C is relatively safe, take caution with vitamin C supplements if you have specific medical conditions or undergo cancer treatments. Speak with your healthcare provider if you have further questions.

12 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Institutes of Health.Vitamin C.Carr AC, Maggini S.Vitamin C and immune function.Nutrients. 2017;9(11):1211. Published 2017 Nov 3. doi:10.3390/nu9111211Hemilä H, Chalker E.Vitamin C reduces the severity of common colds: a meta-analysis.BMC Public Health. 2023;23(1):2468. Published 2023 Dec 11. doi:10.1186/s12889-023-17229-8Padayatty SJ, Levine M.Vitamin C: the known and the unknown and Goldilocks.Oral Dis. 2016;22(6):463-493. doi:10.1111/odi.12446Doseděl M, Jirkovský E, Macáková K, et al.Vitamin C-Sources, physiological role, kinetics, deficiency, use, toxicity, and determination.Nutrients. 2021;13(2):615. Published 2021 Feb 13. doi:10.3390/nu13020615MedlinePlus.Vitamin C.Hill A, Wendt S, Benstoem C, et al.Vitamin C to improve organ dysfunction in cardiac surgery patients-review and pragmatic approach.Nutrients. 2018;10(8):974. Published 2018 Jul 27. doi:10.3390/nu10080974USDA.FoodData Central.Skelin M, Lucijanić T, Klarić DA, et al.Factors affecting gastrointestinal absorption of levothyroxine: a review. 2017.Clinical Therapeutics. doi:10.1016/j.clinthera.2017.01.005Singh DN, Bohra JS, Dubey TP, et al.Common foods for boosting human immunity: A review.Food Sci Nutr. 2023;11(11):6761-6774. Published 2023 Aug 18. doi:10.1002/fsn3.3628Besedovsky L, Lange T, Haack M.The sleep-immune crosstalk in health and disease.Physiol Rev. 2019;99(3):1325-1380. doi:10.1152/physrev.00010.2018Black DS, Slavich GM.Mindfulness meditation and the immune system: a systematic review of randomized controlled trials.Ann N Y Acad Sci. 2016;1373(1):13-24. doi:10.1111/nyas.12998

12 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Institutes of Health.Vitamin C.Carr AC, Maggini S.Vitamin C and immune function.Nutrients. 2017;9(11):1211. Published 2017 Nov 3. doi:10.3390/nu9111211Hemilä H, Chalker E.Vitamin C reduces the severity of common colds: a meta-analysis.BMC Public Health. 2023;23(1):2468. Published 2023 Dec 11. doi:10.1186/s12889-023-17229-8Padayatty SJ, Levine M.Vitamin C: the known and the unknown and Goldilocks.Oral Dis. 2016;22(6):463-493. doi:10.1111/odi.12446Doseděl M, Jirkovský E, Macáková K, et al.Vitamin C-Sources, physiological role, kinetics, deficiency, use, toxicity, and determination.Nutrients. 2021;13(2):615. Published 2021 Feb 13. doi:10.3390/nu13020615MedlinePlus.Vitamin C.Hill A, Wendt S, Benstoem C, et al.Vitamin C to improve organ dysfunction in cardiac surgery patients-review and pragmatic approach.Nutrients. 2018;10(8):974. Published 2018 Jul 27. doi:10.3390/nu10080974USDA.FoodData Central.Skelin M, Lucijanić T, Klarić DA, et al.Factors affecting gastrointestinal absorption of levothyroxine: a review. 2017.Clinical Therapeutics. doi:10.1016/j.clinthera.2017.01.005Singh DN, Bohra JS, Dubey TP, et al.Common foods for boosting human immunity: A review.Food Sci Nutr. 2023;11(11):6761-6774. Published 2023 Aug 18. doi:10.1002/fsn3.3628Besedovsky L, Lange T, Haack M.The sleep-immune crosstalk in health and disease.Physiol Rev. 2019;99(3):1325-1380. doi:10.1152/physrev.00010.2018Black DS, Slavich GM.Mindfulness meditation and the immune system: a systematic review of randomized controlled trials.Ann N Y Acad Sci. 2016;1373(1):13-24. doi:10.1111/nyas.12998

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

National Institutes of Health.Vitamin C.Carr AC, Maggini S.Vitamin C and immune function.Nutrients. 2017;9(11):1211. Published 2017 Nov 3. doi:10.3390/nu9111211Hemilä H, Chalker E.Vitamin C reduces the severity of common colds: a meta-analysis.BMC Public Health. 2023;23(1):2468. Published 2023 Dec 11. doi:10.1186/s12889-023-17229-8Padayatty SJ, Levine M.Vitamin C: the known and the unknown and Goldilocks.Oral Dis. 2016;22(6):463-493. doi:10.1111/odi.12446Doseděl M, Jirkovský E, Macáková K, et al.Vitamin C-Sources, physiological role, kinetics, deficiency, use, toxicity, and determination.Nutrients. 2021;13(2):615. Published 2021 Feb 13. doi:10.3390/nu13020615MedlinePlus.Vitamin C.Hill A, Wendt S, Benstoem C, et al.Vitamin C to improve organ dysfunction in cardiac surgery patients-review and pragmatic approach.Nutrients. 2018;10(8):974. Published 2018 Jul 27. doi:10.3390/nu10080974USDA.FoodData Central.Skelin M, Lucijanić T, Klarić DA, et al.Factors affecting gastrointestinal absorption of levothyroxine: a review. 2017.Clinical Therapeutics. doi:10.1016/j.clinthera.2017.01.005Singh DN, Bohra JS, Dubey TP, et al.Common foods for boosting human immunity: A review.Food Sci Nutr. 2023;11(11):6761-6774. Published 2023 Aug 18. doi:10.1002/fsn3.3628Besedovsky L, Lange T, Haack M.The sleep-immune crosstalk in health and disease.Physiol Rev. 2019;99(3):1325-1380. doi:10.1152/physrev.00010.2018Black DS, Slavich GM.Mindfulness meditation and the immune system: a systematic review of randomized controlled trials.Ann N Y Acad Sci. 2016;1373(1):13-24. doi:10.1111/nyas.12998

National Institutes of Health.Vitamin C.

Carr AC, Maggini S.Vitamin C and immune function.Nutrients. 2017;9(11):1211. Published 2017 Nov 3. doi:10.3390/nu9111211

Hemilä H, Chalker E.Vitamin C reduces the severity of common colds: a meta-analysis.BMC Public Health. 2023;23(1):2468. Published 2023 Dec 11. doi:10.1186/s12889-023-17229-8

Padayatty SJ, Levine M.Vitamin C: the known and the unknown and Goldilocks.Oral Dis. 2016;22(6):463-493. doi:10.1111/odi.12446

Doseděl M, Jirkovský E, Macáková K, et al.Vitamin C-Sources, physiological role, kinetics, deficiency, use, toxicity, and determination.Nutrients. 2021;13(2):615. Published 2021 Feb 13. doi:10.3390/nu13020615

MedlinePlus.Vitamin C.

Hill A, Wendt S, Benstoem C, et al.Vitamin C to improve organ dysfunction in cardiac surgery patients-review and pragmatic approach.Nutrients. 2018;10(8):974. Published 2018 Jul 27. doi:10.3390/nu10080974

USDA.FoodData Central.

Skelin M, Lucijanić T, Klarić DA, et al.Factors affecting gastrointestinal absorption of levothyroxine: a review. 2017.Clinical Therapeutics. doi:10.1016/j.clinthera.2017.01.005

Singh DN, Bohra JS, Dubey TP, et al.Common foods for boosting human immunity: A review.Food Sci Nutr. 2023;11(11):6761-6774. Published 2023 Aug 18. doi:10.1002/fsn3.3628

Besedovsky L, Lange T, Haack M.The sleep-immune crosstalk in health and disease.Physiol Rev. 2019;99(3):1325-1380. doi:10.1152/physrev.00010.2018

Black DS, Slavich GM.Mindfulness meditation and the immune system: a systematic review of randomized controlled trials.Ann N Y Acad Sci. 2016;1373(1):13-24. doi:10.1111/nyas.12998

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