Vitamin C: Do Daily Mega-Doses Accelerate Wound Healing? Protection Status
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by Mary Ellen Posthauer RDN, CD, LD, FAND

Metabolic Roles of Vitamin C

The major function of vitamin C (ascorbic acid) in wound healing is assisting in the formation of collagen, the most important protein of connective tissue. Vitamin C, a water-soluble vitamin found in water-filled foods, dissolves in water and is transported in the bloodstream. Excess amounts are excreted in the urine; however, since the body does not store vitamin C, food sources should be consumed on a regular basis. Vitamin C supplementation has been shown to increase tensile strength and collagen synthesis by assisting in the hydroxylation of lysine and proline, major constituents of collagen.

Vitamin C is the principal water-soluble antioxidant in plasma. As an antioxidant, vitamin C‘s action is twofold: first, by being oxidized itself, vitamin C regenerates already oxidized substances such as iron or copper to their active form; second, in the process, the vitamin removes the damaging oxidizing agent. In the intestines it enhances iron absorption by protecting it from oxidation. Individuals who are taking an iron supplement will increase their iron absorption by eating foods high in vitamin C at the same time. Vitamin C is a cofactor with iron during the hydroxylation of proline and lysine in the production of collagen, making it important for tissue repair and regeneration. Vitamin C and iron deficiencies are both manifested by decreased collagen synthesis, which can result in delayed healing and capillary fragility. Wounds may fail to heal because scar tissue doesn’t form. Ascorbic acid deficiency is also associated with impaired immune function, which can decrease the ability to fight infection.

Deficiency Symptoms

Scurvy, the vitamin C deficiency disease, is rare except in severely malnourished individuals. Vitamin C deficiency symptoms include petechial hemorrhage, bleeding gums, ecchymoses, and hyperkeratosis. Scurvy is easily reversed with the consumption a moderate dose of 100mg daily of vitamin C, which is achieved with the consumption of fruits and vegetables. The current Dietary Reference Intake (DRI) for vitamin C is 90mg for men and 75mg for women. Due to the oxidative damage of nicotine, smokers are encouraged to increase their intake of vitamin C by 35mg. Significant sources are citrus fruits, dark green vegetables, cantaloupe, strawberries, peppers, tomatoes, potatoes, papaya, and mangoes.

Despite the apparent benefits of vitamin C, research has not proven that taking high doses will accelerate pressure ulcer healing. A randomized control trial by Dr. Gerben ter Riet demonstrated no improvement in pressure ulcer healing with 1000mg supplemental vitamin C (1). However, individuals with wounds should continue to consume a balanced diet with a good source of vitamin C daily. Oral nutritional supplements prescribed for individuals with wounds contain vitamin C, along with other vitamins and minerals. If an individual has a poor appetite or does not eat a balanced diet, a daily multivitamin that meets the RDI’s would be appropriate. The multivitamin should be taken with food at a consistent time each day. Taking large doses of vitamin C may cause adverse effects, such as gastrointestinal distress and diarrhea, which may negatively impact wound healing.

1. ter Riet G, Kessels A G, & Knipschild P G. (1995). Randomized clinical trial of ascorbic acid in the treatment of pressure ulcers. J Clin Epidemiol, 48(12), 1453-1460.
2. Vilter RW. Nutritional aspects of ascorbic acid: uses and abuses. West J Med 1980;133:485-492.
3. Molnar JA. Overview of Nutrition and Wound Healing. In: Molnar J, editor. Nutrition and Wound Healing . First Edition ed. Boca Raton, FL: CRC Press; 2007. p. 1-14.
4. Ronchetti IP, Quaglino D, Bergamini G. Ascorbic Acid and Connective Tissue. Subcellular Biochemistry, Volume 25: Ascorbic Acid: Biochemistry and Biomedical Cell Biology. Plenum Press, New York, 1996.

About The Author
Mary Ellen Posthauer RDN, CD, LD, FAND is an award winning dietitian, consultant for MEP Healthcare Dietary Services, published author, and member of the Purdue University Hall of Fame, Department of Foods and Nutrition, having held positions on numerous boards and panels including the National Pressure Ulcer Panel and the American Dietetic Association’s Unintentional Weight Loss work group.

The views and opinions expressed in this blog are solely those of the author, and do not represent the views of WoundSource, Kestrel Health Information, Inc., its affiliates, or subsidiary companies.


There are plenty of studies that have shown that high doses of vitamin C can significantly accelerate wound healing. Here are a few such examples,

I have seen the effect of high doses of vitamin C on the healing rates of my own injuries. It speeds the healing substantially.

While we are in agreement about the function of vitamin C and the role it plays in wound healing, the references noted do not support the administration of mega doses for wound healing. The first reference is a 1982 review which noted the findings could serve as a basis for further studies. The second reference is a study of burn patients. The goal of this study found there was no difference in outcomes but demonstrated the safety in administrating increased doses of vitamin C to decrease fluid requirements and tissue edema. The third reference was a RCT examining the administration of vitamin E and C for severe head injuries.

The 1995 ter Riet RCT was a large study and as quoted in the Cochrane Collaboration titled: Nutritional interventions for preventing and treating pressure ulcers, “this study used a reasonable control intervention and a larger sample size which would suggest that the effect of ascorbic acid on the treatment of pressure ulcers seems to be a least unclear”. In this study, the control group received 10 mg. of ascorbic acid daily and the experimental group 500mg. After 12 weeks the control group had better outcomes.
Promoting the consumption of a diet containing good sources of vitamin C continues to be important intervention for healing wounds. As with all nutritional interventions, more research is needed.

1000mg doses does not constitute a "mega-dose" for those who are megadose proponents, so the study you reference is inadequate, as is the associated Cochrane Collaboration report, to conclusively say anything about megadoses and their effect on tissue repair and regeneration. The typical doses used for oral megadosing is determined by a process called "bowel tolerance", which tolerance is contingent on the heath of the individual. When they are sick the dose may be as high as 100g in a single day while experiencing no adverse bowel effects (I have experienced that myself).

Even at those levels, the amount absorbed and maintained in the bloodstream is limited by the kidney's abilities to flush out "excess" vitamin C, as you mentioned, where the upper level appears to be roughly 300 umol/L. Intravenous Ascorbate can increase this blood-ascorbate concentration by a factor of 100, safely for most people (no G6PD deficiency, no renal issues nor osmotic challenges). There are no studies which have been designed to evaluate the effect on tissue regeneration, but intravenous vitamin C (IVC) is becoming a common practice in the sports industry, even the olympics, to increase, energy, repair and tissue regeneration leading up to and following athletic performance.

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