Vitamin C

Related Terms

Acide ascorbique (French), acide c?vitamique (French), acide iso-ascorbique (French), acide L-ascorbique (French), ?cido asc?rbico (Spanish), antiscorbutic vitamin, ascorbate, ascorbate de calcium, ascorbate de sodium, ascorbic acid (AA), ascorbyl palmitate, calcium ascorbate, cevitamic acid, iso-ascorbic acid, L-ascorbic acid, magnesium ascorbate, palmitate d'ascorbyl (French), selenium ascorbate, sodium ascorbate, vitamina C (Spanish), vitamine antiscorbutique (French), vitamine C (French).

Background

Vitamin C (ascorbic acid) is a water-soluble vitamin, which is needed by the body to form collagen in bones, cartilage, muscle, and blood vessels. Dietary sources of vitamin C include fruits and vegetables, particularly citrus fruits such as oranges.
Severe deficiency of vitamin C causes scurvy. Although rare, scurvy results in severe symptoms and can cause death. People with scurvy are treated with vitamin C and should be under medical supervision.
Many uses for vitamin C have been proposed, but evidence of benefit in scientific studies is lacking. In particular, research on asthma, cancer, and diabetes remains inconclusive, and a lack of benefit has been found for the prevention of cataracts or heart disease.
The use of vitamin C in the prevention or treatment of colds remains controversial. Extensive research has been conducted. Overall, vitamin C lacked an effect on the development of colds and on cold symptoms. However, the duration of the cold shortened slightly. Notably, people living in extreme circumstances, including soldiers in the subarctic, skiers, and marathon runners, had a 50% decrease in the risk of developing a cold. This area merits additional research and may be of particular interest to athletes or people in the military.

Evidence Table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. GRADE *
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. GRADE *


Scurvy is caused by a lack of vitamin C in the diet. Although scurvy is uncommon, it may occur in malnourished individuals, those that need more vitamin C (such as pregnant or breastfeeding women), or infants. If vitamin C is unavailable, orange juice can be used for scurvy in infants. Symptoms should begin to improve in 1-2 days, and end completely within seven days. Treatment should be under strict medical supervision.

 A


Scurvy is caused by a lack of vitamin C in the diet. Although scurvy is uncommon, it may occur in malnourished individuals, those that need more vitamin C (such as pregnant or breastfeeding women), or infants. If vitamin C is unavailable, orange juice can be used for scurvy in infants. Symptoms should begin to improve in 1-2 days, and end completely within seven days. Treatment should be under strict medical supervision.

 A


Vitamin C reduced the risk of developing colds, by roughly 50% in people under physical stress or in extreme conditions, such as soldiers in the subarctic, skiers, and marathon runners. This area merits more research and may be of particular interest to elite athletes or military personnel.

 B


Vitamin C reduced the risk of developing colds, by roughly 50% in people under physical stress or in extreme conditions, such as soldiers in the subarctic, skiers, and marathon runners. This area merits more research and may be of particular interest to elite athletes or military personnel.

 B


Based on scientific research, vitamin C appears to improve absorption of iron or iron supplements taken by mouth. Further research is needed to reach a firm conclusion.

 B


Based on scientific research, vitamin C appears to improve absorption of iron or iron supplements taken by mouth. Further research is needed to reach a firm conclusion.

 B


Vitamin C may decrease the risk of developing urinary tract infections during pregnancy and in the elderly. Further research is needed to confirm this finding.

 B


Vitamin C may decrease the risk of developing urinary tract infections during pregnancy and in the elderly. Further research is needed to confirm this finding.

 B


There is a lack of evidence showing beneficial effects of vitamin C alone in the treatment of AMD, an eye disorder which causes loss of vision. Further research is needed in this area.

 C


There is a lack of evidence showing beneficial effects of vitamin C alone in the treatment of AMD, an eye disorder which causes loss of vision. Further research is needed in this area.

 C


There is limited research on the effects of vitamin C alone on the progression of Alzheimer's disease. Further research is needed before a conclusion can be made.

 C


There is limited research on the effects of vitamin C alone on the progression of Alzheimer's disease. Further research is needed before a conclusion can be made.

 C


Research has shown that vitamin C may improve the absorption of dietary iron. Limited research has shown that vitamin C may improve outcomes of anemia, a disorder where there is a short supply red blood cells. Additional research is needed before a conclusion can be made.

 C


Research has shown that vitamin C may improve the absorption of dietary iron. Limited research has shown that vitamin C may improve outcomes of anemia, a disorder where there is a short supply red blood cells. Additional research is needed before a conclusion can be made.

 C


Limited research showed that vitamin C lacked a clear anti-oxidant effect. Further information is required to form conclusions.

 C


Limited research showed that vitamin C lacked a clear anti-oxidant effect. Further information is required to form conclusions.

 C


Vitamin C may slow disease progression in individuals with osteoarthritis. However, high-quality research is needed to conclude if vitamin C is beneficial for both osteoarthritis and rheumatoid arthritis.

 C


Vitamin C may slow disease progression in individuals with osteoarthritis. However, high-quality research is needed to conclude if vitamin C is beneficial for both osteoarthritis and rheumatoid arthritis.

 C


It has been suggested that low levels of vitamin C may increase the risk of developing asthma. Research on the use of vitamin C in asthma remains inconclusive. More research is needed before a clear conclusion can be drawn.

 C


It has been suggested that low levels of vitamin C may increase the risk of developing asthma. Research on the use of vitamin C in asthma remains inconclusive. More research is needed before a clear conclusion can be drawn.

 C


Ascorbic acid may decrease the severity of symptoms in children with autism, a mental disorder. More trials are needed before a conclusion can be made.

 C


Ascorbic acid may decrease the severity of symptoms in children with autism, a mental disorder. More trials are needed before a conclusion can be made.

 C


Early evidence suggests that vitamin C may help with stomach damage caused by aspirin. More research is needed before a clear conclusion can be drawn.

 C


Early evidence suggests that vitamin C may help with stomach damage caused by aspirin. More research is needed before a clear conclusion can be drawn.

 C


Limited research examined the role of vitamin C in breast cancer. There was a lack of conclusive results. Additional studies are needed.

 C


Limited research examined the role of vitamin C in breast cancer. There was a lack of conclusive results. Additional studies are needed.

 C


Early research suggested that vitamin C may have positive effects in people with severe burns. Additional studies are needed before a conclusion can be made.

 C


Early research suggested that vitamin C may have positive effects in people with severe burns. Additional studies are needed before a conclusion can be made.

 C


Dietary intake of fruits and vegetables high in vitamin C has been associated with a reduced risk of cancer. The role of vitamin C is unclear. Limited research showed that vitamin C supplements lacked a protective effect on certain cancers. Further research is needed to draw conclusions.

 C


Dietary intake of fruits and vegetables high in vitamin C has been associated with a reduced risk of cancer. The role of vitamin C is unclear. Limited research showed that vitamin C supplements lacked a protective effect on certain cancers. Further research is needed to draw conclusions.

 C


Vitamin C has a long history of being used as a part of cancer therapy. Clear evidence of benefit of using vitamin C is lacking. More well-designed studies are needed before a firm conclusion can be made.

 C


Vitamin C has a long history of being used as a part of cancer therapy. Clear evidence of benefit of using vitamin C is lacking. More well-designed studies are needed before a firm conclusion can be made.

 C


Early research showed that vitamin C lacked additional benefit for people with cancer when together with chemotherapy, or drug-therapy for cancer. Additional studies are needed in this area.

 C


Early research showed that vitamin C lacked additional benefit for people with cancer when together with chemotherapy, or drug-therapy for cancer. Additional studies are needed in this area.

 C


Due to limitations in research, the role of vitamin C alone is unclear in chronic venous insufficiency, a disease that occurs when insufficient blood is pumped back to the heart. Additional studies are needed.

 C


Due to limitations in research, the role of vitamin C alone is unclear in chronic venous insufficiency, a disease that occurs when insufficient blood is pumped back to the heart. Additional studies are needed.

 C


In limited research, vitamin C lacked an effect on colon cancer occurrence or death from cancer. Additional studies are needed before a conclusion can be made.

 C


In limited research, vitamin C lacked an effect on colon cancer occurrence or death from cancer. Additional studies are needed before a conclusion can be made.

 C


The use of vitamin C for cold symptom treatment has showed mixed results in human research. Further research is needed in this area.

 C


The use of vitamin C for cold symptom treatment has showed mixed results in human research. Further research is needed in this area.

 C


Clinical research suggests that vitamin C may be beneficial for complex regional pain syndrome, which involves long-term pain usually in an arm or leg. Further research is needed to draw conclusions.

 C


Clinical research suggests that vitamin C may be beneficial for complex regional pain syndrome, which involves long-term pain usually in an arm or leg. Further research is needed to draw conclusions.

 C


The role of vitamin C is unclear in people with cystic fibrosis, a disease with mucus build-up in the body. Additional research is needed in this area.

 C


The role of vitamin C is unclear in people with cystic fibrosis, a disease with mucus build-up in the body. Additional research is needed in this area.

 C


The role of vitamin C alone in dementia is unclear due to the limited research that is available. Further research is needed.

 C


The role of vitamin C alone in dementia is unclear due to the limited research that is available. Further research is needed.

 C


In limited research, the role of vitamin C for diabetic eye disease and diabetic nerve pain was unclear. Well-designed trials are needed.

 C


In limited research, the role of vitamin C for diabetic eye disease and diabetic nerve pain was unclear. Well-designed trials are needed.

 C


In human research, the effects of vitamin C supplementation are mixed regarding the prevention of endometrial cancer, a cancer of the uterus lining. Further research is needed before a conclusion can be made.

 C


In human research, the effects of vitamin C supplementation are mixed regarding the prevention of endometrial cancer, a cancer of the uterus lining. Further research is needed before a conclusion can be made.

 C


Erythropoietic protoporphyria (EPP) is a rare inherited blood disorder characterized by extreme skin-sensitivity to sunlight. More research is needed to determine if vitamin C is beneficial for this condition.

 C


Erythropoietic protoporphyria (EPP) is a rare inherited blood disorder characterized by extreme skin-sensitivity to sunlight. More research is needed to determine if vitamin C is beneficial for this condition.

 C


Vitamin C may help prevent damage to fat and muscle caused by exercise and may improve physical ability. More research is needed before a conclusion can be made.

 C


Vitamin C may help prevent damage to fat and muscle caused by exercise and may improve physical ability. More research is needed before a conclusion can be made.

 C


Limited research showed that vitamin C improved pregnancy rate in women with cysts on their ovaries. Further research is needed to determine the effects of vitamin C supplementation on fertility.

 C


Limited research showed that vitamin C improved pregnancy rate in women with cysts on their ovaries. Further research is needed to determine the effects of vitamin C supplementation on fertility.

 C


Vitamin C supplementation may decrease the risk of gallbladder disease in women. Well-designed trials are needed to draw conclusions.

 C


Vitamin C supplementation may decrease the risk of gallbladder disease in women. Well-designed trials are needed to draw conclusions.

 C


Early evidence suggests that vitamin C supplementation may reduce the risk of abnormal heart rhythms after surgery. Additional studies are needed.

 C


Early evidence suggests that vitamin C supplementation may reduce the risk of abnormal heart rhythms after surgery. Additional studies are needed.

 C


Adding vitamin C to standard therapy (omeprazole, amoxicillin, and clarithromycin) for stomach ulcers due to H. pylori may allow the dose of clarithromycin to be lower. Other research showed that vitamin C lacked an effect on H. pylori infection. Further research is needed to confirm this result.

 C


Adding vitamin C to standard therapy (omeprazole, amoxicillin, and clarithromycin) for stomach ulcers due to H. pylori may allow the dose of clarithromycin to be lower. Other research showed that vitamin C lacked an effect on H. pylori infection. Further research is needed to confirm this result.

 C


In human research, vitamin C supplementation has been shown to decrease blood pressure. Further research is needed in this area.

 C


In human research, vitamin C supplementation has been shown to decrease blood pressure. Further research is needed in this area.

 C


According to studies in humans, vitamin C supplementation may be beneficial in people with high cholesterol. More research is needed in this area.

 C


According to studies in humans, vitamin C supplementation may be beneficial in people with high cholesterol. More research is needed in this area.

 C


Supplementation of mothers with HIV disease with vitamin B, vitamin C, and vitamin E may reduce child mortality and HIV transmission through breast milk. Well-designed studies are needed.

 C


Supplementation of mothers with HIV disease with vitamin B, vitamin C, and vitamin E may reduce child mortality and HIV transmission through breast milk. Well-designed studies are needed.

 C


Due to its antioxidant properties, vitamin C has been used in people with ischemic heart disease, a condition where there is insufficient blood supply to the heart. Early data suggests that vitamin C may have a benefit on blood flow in the heart. Further research is needed to confirm this finding.

 C


Due to its antioxidant properties, vitamin C has been used in people with ischemic heart disease, a condition where there is insufficient blood supply to the heart. Early data suggests that vitamin C may have a benefit on blood flow in the heart. Further research is needed to confirm this finding.

 C


Limited research suggests that vitamin C may reduce the risk of kidney disease from the dye used in coronary angiography, a procedure to examine blood vessels. Additional trials are needed before a conclusion can be made.

 C


Limited research suggests that vitamin C may reduce the risk of kidney disease from the dye used in coronary angiography, a procedure to examine blood vessels. Additional trials are needed before a conclusion can be made.

 C


Consuming vitamin C from dietary sources may lower blood concentrations of lead. Additional studies are needed.

 C


Consuming vitamin C from dietary sources may lower blood concentrations of lead. Additional studies are needed.

 C


Research has shown that vitamin C lacked effects on extending life, or preventing mortality. Further research is needed.

 C


Research has shown that vitamin C lacked effects on extending life, or preventing mortality. Further research is needed.

 C


Administration of vitamin C in individuals with cirrhosis may have some benefit. However, in people with chronic hepatitis C, vitamin C lacked effectiveness. Additional studies are needed before a conclusion can be made.

 C


Administration of vitamin C in individuals with cirrhosis may have some benefit. However, in people with chronic hepatitis C, vitamin C lacked effectiveness. Additional studies are needed before a conclusion can be made.

 C


An oxidant-antioxidant balance may play a role in maintaining proper lung function. Limited studies have examined the role of vitamin C alone for lung diseases. Additional research is needed before a conclusion can be made.

 C


An oxidant-antioxidant balance may play a role in maintaining proper lung function. Limited studies have examined the role of vitamin C alone for lung diseases. Additional research is needed before a conclusion can be made.

 C


Limited research suggests that daily high-dose vitamin C may aid with alkaptonuria, a metabolic disorder where the urine turns black upon touching air. Also, vitamin C may improve tyrosinemia in infants, a genetic disorder of tyrosine metabolism that results in problem with the liver, kidney, and brain. Well-designed trials are needed in this area before a conclusion can be made.

 C


Limited research suggests that daily high-dose vitamin C may aid with alkaptonuria, a metabolic disorder where the urine turns black upon touching air. Also, vitamin C may improve tyrosinemia in infants, a genetic disorder of tyrosine metabolism that results in problem with the liver, kidney, and brain. Well-designed trials are needed in this area before a conclusion can be made.

 C


Vitamin C may prevent nitrate tolerance in people using nitroglycerin under the tongue. Well-designed research is needed in this area before a conclusion can be made.

 C


Vitamin C may prevent nitrate tolerance in people using nitroglycerin under the tongue. Well-designed research is needed in this area before a conclusion can be made.

 C


Limited research showed a lack of benefits and harmful effects of vitamin C given for the first 28 days of life in premature infants. Additional studies are needed before a conclusion can be made.

 C


Limited research showed a lack of benefits and harmful effects of vitamin C given for the first 28 days of life in premature infants. Additional studies are needed before a conclusion can be made.

 C


Research showed that intake of vitamin E, vitamin C, and carotenoids may lack benefit for Parkinson's disease. The effects of vitamin C alone are unclear. More studies are needed.

 C


Research showed that intake of vitamin E, vitamin C, and carotenoids may lack benefit for Parkinson's disease. The effects of vitamin C alone are unclear. More studies are needed.

 C


Limited research suggests that higher intake of vitamin C may be related to improved physical performance and muscle strength in the elderly. Well-designed trials are needed before a conclusion can be made.

 C


Limited research suggests that higher intake of vitamin C may be related to improved physical performance and muscle strength in the elderly. Well-designed trials are needed before a conclusion can be made.

 C


In early research, less plaque on the teeth and less bleeding of the gums were observed after the use of vitamin C chewing gum. Further research is needed to confirm these results.

 C


In early research, less plaque on the teeth and less bleeding of the gums were observed after the use of vitamin C chewing gum. Further research is needed to confirm these results.

 C


The role of vitamin C is unclear in the prevention of pneumonia. Further research is needed to draw conclusions.

 C


The role of vitamin C is unclear in the prevention of pneumonia. Further research is needed to draw conclusions.

 C


It is unclear if vitamin C is beneficial when taken during pregnancy. It has been suggested that preterm birth may increase with vitamin C supplementation. However, early research also shows that vitamin C may lessen the chance of early water breaking. Further research is needed. A healthcare practitioner should be consulted before taking any herbs or supplements during pregnancy.

 C


It is unclear if vitamin C is beneficial when taken during pregnancy. It has been suggested that preterm birth may increase with vitamin C supplementation. However, early research also shows that vitamin C may lessen the chance of early water breaking. Further research is needed. A healthcare practitioner should be consulted before taking any herbs or supplements during pregnancy.

 C


Early research shows conflicting results when taking vitamin C for pressure ulcers. Further research is needed.

 C


Early research shows conflicting results when taking vitamin C for pressure ulcers. Further research is needed.

 C


Vitamin C has been used in prostate cancer treatment. Early evidence shows that vitamin C lacks an effect on decreasing prostate cancer risk. Further research is needed for conclusions to be drawn.

 C


Vitamin C has been used in prostate cancer treatment. Early evidence shows that vitamin C lacks an effect on decreasing prostate cancer risk. Further research is needed for conclusions to be drawn.

 C


Vitamin C with vitamin E may reduce albumin in the urine in people with type 2 diabetes. Further research is needed in this area.

 C


Vitamin C with vitamin E may reduce albumin in the urine in people with type 2 diabetes. Further research is needed in this area.

 C


Creams with 3-10% vitamin C may improve the appearance of wrinkled skin. Further research is needed before a conclusion can be made.

 C


Creams with 3-10% vitamin C may improve the appearance of wrinkled skin. Further research is needed before a conclusion can be made.

 C


A water-based formulation of vitamin C used on the skin may decrease skin irritation after laser treatments for scar and wrinkle removal. Well-designed studies are needed for a conclusion to be drawn.

 C


A water-based formulation of vitamin C used on the skin may decrease skin irritation after laser treatments for scar and wrinkle removal. Well-designed studies are needed for a conclusion to be drawn.

 C


Limited research showed that vitamin C applied to the skin may decrease damage caused by the sun. Further research is needed to confirm this finding.

 C


Limited research showed that vitamin C applied to the skin may decrease damage caused by the sun. Further research is needed to confirm this finding.

 C


Limited evidence suggests that vitamin C may play a role in perifollicular pigmentation, or increased color near the hair follicle. Additional studies are needed before a conclusion can be made.

 C


Limited evidence suggests that vitamin C may play a role in perifollicular pigmentation, or increased color near the hair follicle. Additional studies are needed before a conclusion can be made.

 C


Evidence is mixed for the use of vitamin C for decreasing the risk of stroke. More research is needed in this area.

C


Evidence is mixed for the use of vitamin C for decreasing the risk of stroke. More research is needed in this area.

C


Tetanus is a severe infection that may be prevented by vaccination. Vitamin C may prevent death from tetanus infection. However, more high-quality studies are needed.

 C


Tetanus is a severe infection that may be prevented by vaccination. Vitamin C may prevent death from tetanus infection. However, more high-quality studies are needed.

 C


The effects of vitamin C in people with diabetes are mixed. Additional studies are needed.

 C


The effects of vitamin C in people with diabetes are mixed. Additional studies are needed.

 C


Early research shows that vitamin C used in the vagina may help with vaginitis, or infection and inflammation of the vagina. Further research is needed to confirm this finding.

 C


Early research shows that vitamin C used in the vagina may help with vaginitis, or infection and inflammation of the vagina. Further research is needed to confirm this finding.

 C


Research for using vitamin C for cataracts, a disease where the vision becomes cloudy, produced mixed results. Further research is needed to draw conclusions.

 D


Research for using vitamin C for cataracts, a disease where the vision becomes cloudy, produced mixed results. Further research is needed to draw conclusions.

 D


Extensive research has shown that vitamin C taken by mouth lacked an effect on cold prevention.

D


Extensive research has shown that vitamin C taken by mouth lacked an effect on cold prevention.

D


Foods containing vitamin C have been linked to a lower risk of heart disease. However, research has shown that taking vitamin C supplements lacks an effect on heart disease prevention. Further research is needed.

 D


Foods containing vitamin C have been linked to a lower risk of heart disease. However, research has shown that taking vitamin C supplements lacks an effect on heart disease prevention. Further research is needed.

 D
* Key to grades

A: Strong scientific evidence for this use
B: Good scientific evidence for this use
C: Unclear scientific evidence for this use
D: Fair scientific evidence for this use (it may not work)
F: Strong scientific evidence against this use (it likley does not work)
* Key to grades

A: Strong scientific evidence for this use
B: Good scientific evidence for this use
C: Unclear scientific evidence for this use
D: Fair scientific evidence for this use (it may not work)
F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory

The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

Dosing

Adults (over 18 years old)
The recommended daily intake by the U.S. Food and Nutrition Board of the Institute of Medicine for men more than 18 years old is 90 milligrams of vitamin C daily; for women more than 18 years old, it is 75 milligrams daily; for pregnant women more than 18 years old, it is 85 milligrams daily; and for breastfeeding women more than 18 years old, it is 120 milligrams daily. Recently, some experts have questioned whether the recommended daily intake should be raised. Others have recommended an additional 35 milligrams daily intake in some individuals, such as smokers.
The upper limit of intake (UL) should avoid exceeding 2,000 milligrams daily in men or women more than 18 years old (including pregnant or breastfeeding women).
Vitamin C administered by mouth or injection is effective for curing scurvy. 100-250 milligrams of vitamin C was given by mouth four times daily for one week. Some experts have recommended 1-2 grams daily for two days, followed by 500 milligrams daily for one week. Symptoms should begin to improve within 24-48 hours, and be completely cured within seven days. Treatment should be under strict medical supervision. For asymptomatic vitamin C deficiency, lower daily doses may be used.
For antioxidant effects, 200-1,000 milligrams of vitamin C has been given daily for four weeks to a year; 300-3,000 milligrams of vitamin C has been injected into the vein, from a single dose to a duration of eight weeks.
For breast cancer prevention, 500 milligrams of vitamin C has been taken by mouth daily.
For cancer prevention, 120-2,000 milligrams of vitamin C has been taken by mouth daily for six to eight years.
For preventing the common cold in people in extreme environments, 200 milligrams or more of vitamin C has been taken by mouth daily for up to 14 days.
For preventing the common cold in general, 30-3,000 milligrams of vitamin C has been taken by mouth daily for two weeks to eight winters.
For treating the common cold, 200 milligrams to 3 grams have been taken by mouth daily for three to five days or longer.
For preventing complex regional pain syndrome in people with wrist fractures, 500 milligrams of vitamin C has been taken by mouth daily for 50 days.
For fertility, 750 milligrams of vitamin C has been taken by mouth daily for six months.
For heart conditions, 2 grams of vitamin C has been given by mouth before surgery, followed by 1 gram daily for five days.
For H. pylori infection, 400-1,000 milligrams of vitamin C has been given by mouth daily for up to seven weeks.
For high blood pressure, 60-4,000 milligrams of vitamin C has been given by mouth daily for 6-16 weeks.
For kidney disease, 3 grams of vitamin C was given by mouth before the kidney-toxic procedure, then 2 grams after the procedure in the evening and again the following morning; 100-200 milligrams of vitamin C has been taken by mouth daily.
For liver disease, 120-3,000 of milligrams vitamin C has been taken by mouth daily for one day to six months; effectiveness on liver disease was lacking.
For life extension, 60-2,000 milligrams of vitamin C has been taken by mouth daily for one month to 9.5 years.
For preventing nitrate tolerance, 3-6 grams of vitamin C has been taken by mouth daily.
For pregnancy, 100-1,000 milligrams of vitamin C has been taken by mouth up to four times daily during pregnancy until delivery.
For prostate cancer, 500 milligrams of vitamin C has been taken by mouth daily for an average of eight years.
For anemia, 200-300 milligrams of vitamin C has been injected into the vein three times weekly, for 3-6 months.
For preventing gout, 500-1,500 milligrams of vitamin C from food and/or supplements has been taken daily.
For skin aging, preparations containing 5-10% vitamin C were applied on the skin daily.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Interactions

Interactions with Drugs
Vitamin C in high doses may interfere with the blood-thinning effects of aspirin, anticoagulants such as warfarin(Coumadin?) or heparin, and anti-platelet drugs such as clopidogrel (Plavix?).
Vitamin C may affect blood sugar levels. Caution is advised when using medications that may also affect blood sugar. People taking insulin or drugs for diabetes by mouth should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.
Vitamin C may affect blood pressure. Caution is advised in people taking agents that affect blood pressure.
Vitamin C may also interact with acetaminophen, acidifying agents, agents for Parkinson's disease, agents that affect the immune system, agents that increase urine flow, agents used for asthma, agents used for the heart, lungs, stomach or intestines, agents used for the teeth, eyes or the skin, agents used to regulate heart rate, aldose reductase inhibitors, antacids, antibiotics, anticancer drugs, aspirin, barbiturates, birth control taken by mouth, cholesterol-lowering agents, estrogens, fluphenazine, HIV medications, indinavir, kidney agents, levodopa, nicardipine, nicotine-containing products (such as cigarettes, cigars, chewing tobacco, or nicotine patches), progesterones, proton pump inhibitors (PPIs), and salicylates.

Attribution

This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

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