National Institute of Diabetes and Digestive and Kidney Diseases researchers injected immune-deficient mice with cells from three aggressive human cancers — ovarian and pancreatic tumors, plus a form of brain cancer called glioblastoma — and found that vitamin C injections slowed tumour growth by up to 53%.

By injecting into the bloodstream, it is possible to get much larger amounts of the vitamin to a tumor than is possible with oral supplements. Intravenous vitamin C could be a useful addition to conventional cancer therapy, but there is little evidence that it works in humans. Safety trials are planned.