Overview

This cancer information summary provides an overview of the use of intravenous (IV) vitamin C (also known as ascorbate or L-ascorbic acid) as a treatment for people with cancer. This summary includes a brief history of early clinical trials of the use of IV vitamin C; reviews of laboratory, animal, and human studies; and current clinical trials.

This summary contains the following key information:

• Vitamin C is an essential nutrient with redox functions at normal physiologic concentrations.
• Case series and observational studies from the 1970s of cancer patients who received IV vitamin C seemed to indicate a clinical benefit.
• Two early randomized placebo-controlled trials that used oral vitamin C (10 g/d) without IV vitamin C noted no significant differences between ascorbate-treated and placebo -treated groups for symptoms, performance status, or survival.
• Laboratory studies have reported that IV vitamin C has redox properties and decreased cell proliferation in prostate, pancreatic, hepatocellular, colon, mesothelioma, and neuroblastoma cell lines.
• IV vitamin C has been generally well tolerated in clinical trials.
• IV administration of vitamin C of doses over 500 mg produces much higher blood concentrations of ascorbate than oral administration of the same dose.
• The use of IV vitamin C alone as ascorbate versus ascorbate formulations plus certain standard cancer therapies have been shown to be well tolerated in clinical trials.
• Two studies that used IV vitamin C in cancer patients reported improved quality of life and decreases in cancer-related toxicities.
• Although early observations from preclinical and clinical trials of IV vitamin C with and without conventional cancer therapies appear promising and the therapy well tolerated, these studies have several limitations due to lack of rigor in trial design.

Many of the medical and scientific terms used in this summary are hypertext linked (at first use in each section) to the NCI Dictionary of Cancer Terms, which is oriented toward nonexperts. When a linked term is clicked, a definition will appear in a separate window.

Reference citations in some PDQ cancer information summaries may include links to external websites that are operated by individuals or organizations for the purpose of marketing or advocating the use of specific treatments or products. These reference citations are included for informational purposes only. Their inclusion should not be viewed as an endorsement of the content of the websites, or of any treatment or product, by the PDQ Integrative, Alternative, and Complementary Therapies Editorial Board or the National Cancer Institute.