National Cancer Institute
at the National Institutes of Health
- Vitamin C is a nutrient found in food and dietary supplements. It is an antioxidant and also plays a key role in making collagen (see Question 1).
- High-dose vitamin C has been studied as a treatment for patients with cancer since the 1970s (see Question 2).
- High-dose vitamin C may be given by intravenous (IV) infusion or taken by mouth (see Question 2).
- Laboratory studies have shown that high doses of vitamin C may slow the growth and spread of prostate, pancreatic, liver, colon, and other types of cancer cells (see Question 5).
- Some laboratory studies have shown that combining vitamin C with anticancer therapies may be helpful, while other studies have shown that certain forms of vitamin C may make chemotherapy less effective (see Question 5).
- Animal studies have shown that high-dose vitamin C treatment blocks tumor growth in certain models of pancreatic, liver, prostate, and ovarian cancers, sarcoma, and malignant mesothelioma (see Question 5).
- Some animal studies have shown that combining vitamin C with anticancer therapies may be helpful, while other studies have shown that vitamin C may interfere with the anticancer action of some drugs (see Question 5).
- Some human studies of IV vitamin C or vitamin C taken by mouth in patients with cancer have shown improved quality of life, as well as improvements in physical, mental, and emotional functions, symptoms of fatigue, nausea and vomiting, pain, and appetite loss (see Question 6).
- Studies of vitamin C combined with other drugs in patients with cancer have shown mixed results (see Question 6).
- Intravenous high-dose ascorbic acid has caused very few side effects in clinical trials (see Question 7).
- The U.S. Food and Drug Administration (FDA) has not approved the use of high-dose vitamin C as a treatment for cancer or any other medical condition (see Question 9).