Cold sores are painful, often itchy, fluid-filled blisters that usually appear on the lips or, sometimes, the inside of the mouth or surrounding facial skin. The University of Maryland Medical Center estimates that 90 percent of American adults are infected with the herpes simplex virus that causes cold sores. Some never experience cold sores, while others suffer repeated bouts. Vitamin C has attracted attention as a natural remedy for cold sores.
History
Interest in vitamin C as a treatment for cold sores dates back to a 1936 case series published in the now-defunct journal "Annals of Dermatology and Syphiligraphie." In that series, Swiss dermatologist Ivor Dainow, MD, describes how oral and intravenous vitamin C reduced the severity and duration of herpes simplex symptoms in eight patients. The following year, a team of Columbia University researchers led by Margaret Holden, PhD, confirmed that vitamin C inactivated the herpes simplex virus in test tubes.
Dose
Although a 1978 study found that doses as low as 200 mg, three times a day, cut cold sore healing time in half, modern clinicians recommend higher doses. In the 2007 edition of "Integrative Medicine," University of Wisconsin professor David Rakel, MD, recommends 1,000 mg, five times per day. In the December 2005 issue of "Alternative Medicine Reviews," holistic medicine specialist Alan R. Gaby, M.D. recommends 2,000 mg, five times per day. Dr. Gaby also recommends lower doses---500 to 3,000 mg per day---to prevent new cold sore outbreaks.
Risks
High doses of oral vitamin C can cause diarrhea. People who experience diarrhea should try increasing the dose gradually, in increments of 1,000 mg per day until the goal dose is attained. In the 2007 edition of "Haddad and Winchester's Clinical Management of Poisoning Overdose," pharmacist Allison A. Mueller and toxicologist Fred M. Henretig recommend that people with a history of kidney stones, iron overload or G6PD deficiency abstain from using Vitamin C supplements because the supplements can make these conditions worse. Mueller and Henretig also caution that high doses of vitamin C supplements may decrease the effectiveness of oral contraceptives.
Benefits
Dr. Rakel says that, when started at the first sign of symptoms, vitamin C supplements taken for three days reduce cold sore healing time from an average of 10 days to about 4.4 days. Dr. Gaby claims that low, daily doses of vitamin C might prevent cold sore outbreaks altogether, although he acknowledges that there are no studies to prove this. Compared to prescription antiviral drugs, vitamin C supplements are less costly, more natural and readily available to those who lack the time or means to see a doctor.
Considerations
Vitamin C supplements do not replace conventional medical care for cold sores or any other condition. As with any over-the-counter product, people who take vitamin C supplements should share this information with their health care providers. Most cold sores resolve within 10 to 14 days with no treatment at all. People who experience severe, frequent or long-lasting cold sores should see a doctor.
References
- University of Maryland Medical Center: Herpes Simplex
- "Alternative Medicine Reviews"; Natural Remedies for Herpes Simplex; Alan R. Gaby, M.D. ; Dec. 2005
- "Integrative Medicine"; David Rakel, M.D.; 2007
- "Annals of Dermatology and Syphiligraphie"; Treatment of Herpes with Ascorbic Acid; Ivor Dainow, M.D.; July 1936
- "Haddad and Winchester's Clinical Management of Poisoning and Overdose"; Michael W. Shannon, M.D., M.P.H. et al. (Eds.); 2007
- "Journal of Immunology"; Further Experiments on the Inactivation of Herpes Virus by Vitamin C; Margaret Holden, Ph.D. et al.; 1937
