Vitamin C Uses

Vitamin C is used to prevent and treat vitamin C deficiency caused by poor diet, lifestyle factors, and certain medical conditions. Potential causes of vitamin C deficiency include: 

• A diet low in food sources of vitamin C, such as citrus fruits, orange juice, red bell peppers, and leafy green vegetables.
• Cooking methods such as high-heat cooking and prolonged cooking times that can destroy vitamin C in food sources.
• Lifestyle factors such as smoking and excessive alcohol use, which can deplete plasma ascorbic acid (vitamin C levels in the body) due to increased oxidative stress.
• Medical conditions such as eating disorders and gastrointestinal conditions, which can lead to decreased absorption of nutrients from the digestive tract.
• Increased requirements of vitamin C during pregnancy and lactation; in people who have undergone surgery; and burn victims.

Vitamin C supplementation is used for both primary prevention (preventing vitamin C deficiency from developing) and secondary prevention (detecting and treating vitamin deficiency early in high-risk populations). 

Your doctor can make a diagnosis of vitamin C deficiency based on symptoms such as tiredness, weakness, irritability, unusual bruising and bleeding, bleeding gums, dry skin, dry hair, anemia, and scurvy (severe vitamin C deficiency). Vitamin C status can be checked with a blood test to measure plasma vitamin C levels.

There may be other uses of vitamin C—your pharmacist or doctor can give you further drug information. 

Cancer: Some studies have shown that high-dose vitamin C and intravenous ascorbic acid (vitamin C injections) may reduce cancer-related side effects and improve quality of life in cancer patients. Vitamin C intake in supplement form has been studied in people with pancreatic cancer, breast cancer, colorectal cancer, melanoma, and others. Research also does not suggest a strong link between vitamin C intake and breast cancer risk or the risk of other cancers. The FDA has not approved vitamin C as a cancer treatment. 

Cardiovascular disease: Randomized controlled trials such as the Women’s Antioxidant Cardiovascular Study (WCAS) have found that taking antioxidants (vitamin C, vitamin E, beta carotene) has no effect on cardiovascular events in women at high risk for cardiovascular disease. A systematic review of studies shows that the links between blood pressure and vitamin C intake are inconsistent (high blood pressure is a major risk factor for cardiovascular disease).

Common cold: Randomized controlled trials have found that vitamin C intake in the form of supplements does not prevent respiratory infections like common colds, but it may have minimal benefits in reducing the severity and length of the illness.

Eye conditions: Taking vitamin C supplements along with certain other antioxidant vitamins and minerals may prevent the worsening of an eye condition called age-related macular degeneration (AMD). Randomized clinical trials also suggest that people with a higher dietary vitamin C intake have a reduced risk of developing cataracts.

Skin health: Vitamin C serums and skin creams contain high concentrations of vitamin C to stimulate collagen synthesis in the skin. Vitamin C also has antioxidant properties, and along with other antioxidant vitamins, is believed to protect the skin from damage caused by ultraviolet (UV) rays in sunlight. However, research has not shown that topical vitamin C has proven benefits. Very small amounts of vitamin C penetrate the skin surface. Scientists say taking antioxidants (vitamin C and others) through food and supplements is more effective. 

Kidney stones: Studies suggest that a high intake of vitamin C may be a risk factor for kidney stones.

Gout: Higher vitamin C intake may have a protective effect against gout, a condition in which painful uric acid crystals form in the joints.

Vitamin C Mechanism of Action

Vitamin C is a supplement. It works by filling gaps in the diet or replacing vitamin C in people with low serum vitamin C concentrations (low levels of vitamin C) in their body. 

Vitamin C Doses

The recommended dietary allowance (RDA) and dietary reference intakes for vitamin C in milligrams (mg) per day are listed below. This is the amount of vitamin C that should be consumed daily as recommended by the Food and Nutrition Board:

• Infants 0-6 months: 40 mg 
• Infants 7-12 months: 50 mg
• Toddlers 1-3 years: 15 mg
• Young children 4-8 years: 25 mg
• Pre-teens 9-13 years: 45 mg
• Teenagers 14-18 years: 75 mg for males and 65 mg for females
• Adults 19 years and older: 90 mg for males and 75 mg for females
• Pregnant: 80 to 85 mg per day
• Lactating: 115 to 120 mg per day

Vitamin C comes in the form of oral tablets, chewable tablets, gummies, and a liquid solution to take by mouth. The recommended dose for adults and children 12 years of age and older is 500 mg of a vitamin C supplement once daily. The tolerable upper intake level of vitamin C for adults is 2,000 mg per day.