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vitamin C, ascorbic acid
How is this product usually used?
Vitamin C is usually taken orallyorallyto be taken by mouth (swallowed) (by mouth). It is available in forms such as chewable tablets and gummies, capsules, tablets, powders, strips, liquids, and lozenges. Vitamin C is also available in an injectable form, to be given subcutaneously (into skin fat), intramuscularly (into muscles), or intravenously (into veins).
Table 1 lists the usual dose range and the Recommended Dietary Allowance for vitamin C for different age groups. People with vitamin C deficiency might need doses at or above the RDA.
Table 1. Usual daily dose range and RDA for vitamin C for different age groups
Vitamin C (mg/day)
Usual daily dose
Your health care provider may have recommended using this product in other ways. Contact a health care provider if you have questions.
What is this product used for?
Vitamin C is important in maintaining overall good health, especially because of its antioxidantantioxidanta chemical substance that prevents cellular damage from free radicals property. Vitamin C helps the body metabolize fats and proteins. It is important in production of collagen (protein found in skin) and other connective tissues. It helps develop and maintain healthy gums, teeth, bones, and cartilage. It can also help with wound healing.
At doses at or above the RDA, vitamin C supplements have also been used to treat and prevent vitamin C deficiency and associated diseases, including scurvyscurvya condition caused by vitamin C deficiency with symptoms of nausea, weakness, loss of hair and teeth, and bleeding gums (a condition caused by low levels of vitamin C, with symptoms of nausea, weakness, hair and tooth loss, and bleeding gums).
There have also been studies of vitamin C in common colds and cancer prevention.
There is a lot of controversy around using vitamin C to treat the common cold. Many studies have shown that high amounts can shorten the duration of cold symptoms by up to 1.5 days and reduce symptom severity for some people if it is taken on a continuous basis. However, taking large amounts of vitamin C can cause side effects, and it is generally not recommended for everyone. There is no benefit to using vitamin C to prevent a cold, and it doesn't appear to reduce the severity or duration of a cold once the symptoms have started.
Vitamin C may possibly reduce the risk of developing cancer, but research is still ongoing. One study did not find a lower risk of cancer among people who received a combination of vitamins C, E, and beta-carotene (a form of vitamin A). More research needs to be done to determine the role of vitamin C in preventing cancer.
Vitamin C has also been studied for heart diseases, urinary tract infection, arthritis, fertility, gallbladder disease, high blood pressure, high cholesterol, etc. However, there is not enough reliable evidence for these uses and additional studies are required to confirm the benefits of vitamin C in these conditions.
Your health care provider may have recommended this product for other conditions. Contact a health care provider if you have questions.
What else should I be aware of?
Vitamin C is generally safe in most people if taken in recommended amounts. Reported side effects include nausea, vomiting, diarrhea, dizziness, fatigue, flank pain, flushing, headache and stomach cramps, especially with high amounts of vitamin C.
People with a history of kidney stones or kidney problems or are taking medications toxic to the kidneys should talk to a health care professional before starting on vitamin C.
Taking vitamin C together with iron supplements may help to increase the amount of iron absorbed into your body.
Vitamin C might interact with chemotherapy and radiation therapy, however it is unclear whether vitamin C positively or negatively affect these treatments. Talk to your oncologist if you are being treated for cancer before taking vitamin C.
Vitamin C supplements may also interact with other medications such as warfarin, aluminum, niacin, phosphate binders, estrogens, acetylsalicylic acid (ASA), heartburn or stomach medications, and cholesterol-lowering ("statin") medications. Talk to your health care professional before using this supplement.
Women who are pregnant or breast-feeding can safely take oral supplements of vitamin C in recommended amounts.
Before taking any new medications, including natural health products, speak to your physician, pharmacist, or other health care provider. Tell your health care provider about any natural health products you may be taking.
- Dattani S. Serving up antioxidants. Pharmacy Practice 2004;20(7):30-39. www.pharmacygateway.ca/pdfs/2004/07/PPR_07_30.pdf
- Vitamin C (monograph). Natural Medicines Comprehensive Database (subscription required). Accessed online 4 July 2012.
- Health Canada. Licensed Natural Health Products database. Vitamin C. http://www.hc-sc.gc.ca/dhp-mps/prodnatur/applications/licen-prod/monograph/mono_vitamin_c-eng.php (Accessed 4 July 2014)
- Heart Protection Study Collaborative Group. MRC/BHF Heart Protection Study of antioxidant vitamin supplementation in 20,536 high-risk individuals: a randomized placebo-controlled trial. Lancet 2002;360:23-33.
- Hemila H, Chalker E., Douglas B. Vitamin C for preventing and treating the common cold. Cochrane Database of Systematic Reviews 2007;3
- American College of Physicians. Ascorbic acid monograph. ACP PIER & AHFS DI® Essentials 2010. Accessed 8 June 2010.
- Vitamin C (monograph). Natural Standard database (subscription required). Accessed online 4 July 2014.
- Vitamin C. National Institutes of Health – Office of Dietary Supplements. http://ods.od.nih.gov/factsheets/VitaminC-QuickFacts/. Accessed 4 July 2014
- Vitamin C. Lexicomp. www.lexi.com (subscription required). Accessed 4 July 2014
- Vitamin C. e-CPS. www. e-therapeutic.ca (subscription required). Accessed 4 July 2014
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