Supplement

Intravenous vitamin C (high doses)

Ascorbate at pharmacological doses given intravenously, studied as an adjunct in cancer: well tolerated and with a signal of better quality of life and less chemotherapy toxicity, but WITHOUT demonstrated survival benefit. It does not replace cancer treatment.

Only in a clinical setting and under oncology supervision, in trials up to ~1.5 g/kg IV. The oral route does not reach pharmacological concentrations (older oral trials showed no benefit).

It depends on the case; there is no single guideline.

Precautions

Contraindicated in G6PD deficiency (hemolysis), kidney disease, and risk of kidney stones (oxalate). May interfere with some chemotherapy drugs (e.g. bortezomib) according to preclinical data. Never as an alternative to cancer treatment.

Effect by goal · level of evidence

Cancer: quality of life and chemotherapy toxicity

improves (modest) Low-moderate small studies (A)

NCI PDQ summary: at pharmacological doses ascorbate acts as a pro-oxidant (generates H2O2) and is well tolerated up to ~1.5 g/kg. Two studies describe better quality of life and fewer toxicities; in ovarian cancer (2014, 27 patients) added to carboplatin/paclitaxel it reduced chemotherapy toxicity. Small studies without rigorous design.

See the study (small studies) →

Cancer: survival and tumor regression

no clear effect Low no phase III (A)

No phase III trial has shown survival benefit. In pancreatic cancer (phase I with gemcitabine) only stable disease; in prostate cancer it did not lower PSA nor was there regression; randomized trials with oral vitamin C showed no benefit in symptoms or survival. The glioblastoma/lung data are pilots of 13-14 patients against historical controls.

See the study (no phase III) →

In depth

⏱ 2 min read

Unlike oral vitamin C, intravenous vitamin C at pharmacological doses reaches millimolar plasma concentrations and acts as a pro-oxidant: it generates hydrogen peroxide that selectively damages tumor cells in culture. That is the rationale for its study as an adjunct in cancer.

What human trials say (NCI PDQ summary): it is well tolerated up to ~1.5 g/kg with prior screening, and there is a signal of better quality of life and less chemotherapy toxicity (ovarian cancer, 2014). But no phase III trial has shown a survival benefit: in pancreatic cancer only stable disease, in prostate cancer no response, and the older oral trials were negative. Contraindicated in G6PD deficiency and kidney disease; it may interfere with some chemotherapy drugs. An adjunct under study, never an alternative to cancer treatment.

NCI PDQ. Intravenous Vitamin C (PDQ) – Health Professional Version. NCBI Bookshelf NBK121338.

Information, not medical advice. Scientific evidence reflects the quality of the studies.