Megadose vitamin C ('orthomolecular' ascorbate therapy)
oral · 1970–present
SHORT PITCH (AS SOLD)
Multi-gram daily doses of vitamin C, far beyond the amount needed to prevent scurvy, promoted by a two-time Nobel laureate as a way to prevent and shorten the common cold, and, given intravenously, to dramatically extend survival in terminal cancer.
THE ACTUAL EVIDENCE
The 1970 common-cold claim rested substantially on a single trial of Swiss schoolchildren at a ski camp, extrapolated to the general population; a 2013 Cochrane systematic review (Hemilä & Chalker, 29 trial comparisons, 11,306 participants) found no reduction in cold incidence from regular megadose supplementation in the general community (pooled risk ratio 0.97, 95% CI 0.94-1.00), only in a subgroup under brief extreme physical/cold stress (RR about 0.48-0.50), with a modest 8%-14% reduction in cold duration. The cancer claim rested on two Cameron-Pauling retrospective, non-randomized, unblinded studies (PNAS 1976 and 1978) reporting roughly four-fold longer survival in ascorbate-treated terminal patients versus historical hospital controls. Two Mayo Clinic randomized, double-blind, placebo-controlled trials (Creagan et al., NEJM 1979; Moertel et al., NEJM 1985) found no survival, symptom, or tumor-response benefit from high-dose oral vitamin C in advanced-cancer patients, the second explicitly designed to remove the one design difference (prior chemotherapy exposure) Pauling had publicly objected to in the first. The National Cancer Institute's PDQ summary (last revised 28 May 2024) states the FDA has not approved high-dose vitamin C for any medical condition, and that current evidence, including for the intravenous route (which does reach far higher plasma concentrations than oral dosing), does not establish a cancer-treatment benefit.
PRACTITIONERS
INGREDIENTS
CASES
CLAIMS
- Regular megadose supplementation with vitamin C (on the order of 1-3 grams per day or more) meaningfully reduces the incidence of the common cold in the general population, in addition to modestly shortening its duration and severity. refuted
- High-dose ascorbate (10 g/day intravenous, then oral maintenance) prolongs survival in terminal cancer patients roughly four-fold compared to patients not receiving it, and a meaningful minority survive more than a year versus almost none of the untreated comparison group. refuted
- Vitamin C combined with the amino acid lysine (and related lipoprotein(a)-binding inhibitors) prevents and can reverse occlusive cardiovascular disease by causing lipoprotein(a) to release from arterial-wall plaque. unreplicated
SOURCES
- Supplemental ascorbate in the supportive treatment of cancer: Prolongation of survival times in terminal human cancer (1976)
- Supplemental ascorbate in the supportive treatment of cancer: reevaluation of prolongation of survival times in terminal human cancer (1978)
- Failure of high-dose vitamin C (ascorbic acid) therapy to benefit patients with advanced cancer. A controlled trial (1979)
- High-dose vitamin C versus placebo in the treatment of patients with advanced cancer who have had no prior chemotherapy. A randomized double-blind comparison (1985)
- Vitamin C for preventing and treating the common cold (2013)
- Prevention and treatment of occlusive cardiovascular disease with ascorbate and substances that inhibit the binding of lipoprotein (a) (1994)
- Vitamin C and the Common Cold (1970)
- Cancer and Vitamin C: A Discussion of the Nature, Causes, Prevention, and Treatment of Cancer with Special Reference to the Value of Vitamin C (1993)
- Intravenous High-Dose Vitamin C in Cancer Therapy (2020)
- High-Dose Vitamin C (PDQ): Patient Version (2024)
- How the vitamin-industrial complex swindled America (2015)
- High-Dose IV Vitamin C (IVC) (2026)
NOTES
The intervention has two documented phases sharing one underlying claim: that vitamin C, taken in doses far above what corrects dietary deficiency, has powerful pharmacological effects beyond preventing scurvy. The first phase (from 1970) promoted oral megadoses against the common cold; the second (from 1976) promoted intravenous-then-oral megadoses against terminal cancer, developed with Scottish surgeon Ewan Cameron at Vale of Leven Hospital in Scotland. Both claims were tested directly in controlled trials after Pauling’s initial publications, and both failed to replicate the scale of benefit originally reported. Oral vitamin C nonetheless remains one of the most widely sold dietary supplements in the world, and high-dose intravenous ascorbate is still offered today by integrative and naturopathic clinics as a cancer therapy, on evidence the National Cancer Institute continues to describe as not establishing a treatment benefit.