Why did Mayo Clinic studies challenge Linus Pauling’s claims about vitamin C and cancer?

Linus Pauling advocated for the use of high-dose vitamin C as a treatment for cancer, a claim he and collaborator Ewan Cameron detailed in their 1979 book, Cancer and Vitamin C. While Pauling’s own institute-funded animal studies appeared to support these ideas, the Mayo Clinic conducted rigorous investigations involving human cancer patients that failed to corroborate his findings.1

These clinical results led the medical establishment to reject Pauling’s claims regarding the efficacy of vitamin C in treating cancer. Consequently, Pauling’s later work in this area was met with significant skepticism, as his conclusions could not be replicated in controlled human trials.1