A popular oral supplement especially for colds and flu, vitamin C has also been used intravenously. Is there a scientific basis to this controversial therapy? The recommended daily intake (RDA) for vitamin C (ascorbic acid) is 60 mg. This is enough to prevent scurvy, but there has long been a debate about whether larger doses can be helpful. Humans are, after all, among the rare mammals who cannot produce their own vitamin C. It has been suggested that if we did, our production would amount to several grams a day. Many people take large doses of the vitamin when they catch a cold, though not all studies have shown any benefit to this practice. Proponents of the vitamin have criticized those studies for using too low doses. We do know that vitamin C is safe even in very large amounts, although it can cause stomach upset and diarrhea. This may be lessened by taking a buffered (salt) form, such as calcium ascorbate.Klenner was also an advocate of using intravenous vitamin C for cancer, which has later become the main use of this therapy. For a long time it has been scoffed at as quackery, with studies finding little or no benefit – but most of these studies were done using oral vitamin C. In contrast, a recent study conducted by the National Institutes of Health (NIH) found that high concentrations of vitamin C (achieved by I.V. doses similar to those used by Klenner) had anticancer effects in 75 percent of the tested cancer cell lines. Non-cancerous cells were unaffected. Tumor weight was reduced by 41-53 percent in animals with advanced cancer.
Intravenous Vitamin C