Is vitamin C infusion useful in patients with malignancy (cancer)?

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Last updated: February 26, 2025View editorial policy

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From the Guidelines

Vitamin C infusion is not recommended as a standard treatment for patients with malignancy due to lack of high-quality evidence supporting its effectiveness in reducing cancer incidence or improving outcomes. The most recent and relevant study, 1, published in 2021 in the Clinical Nutrition journal, found that long-term supplementation with vitamin C (500 mg/day) and vitamin E (400 IU/day) had no effect on cancer incidence in a large cohort of US physicians. This study suggests that vitamin C supplementation, even at high doses, does not have a significant impact on cancer prevention or treatment.

When considering the use of vitamin C infusions in cancer patients, it is essential to weigh the potential benefits against the risks and limitations. While some studies propose that high-dose intravenous vitamin C (IVC) may have pro-oxidant effects that could selectively damage cancer cells, the evidence is largely theoretical and not supported by robust clinical trials. Typical protocols for IVC therapy involve doses ranging from 0.4g/kg to 1.5g/kg body weight, administered 1-3 times weekly, but these regimens require careful medical supervision due to potential interactions with chemotherapy drugs and risks in patients with renal impairment, G6PD deficiency, or other conditions.

Key considerations for clinicians and patients include:

  • Lack of high-quality evidence supporting the use of vitamin C infusions in cancer treatment
  • Potential risks and interactions associated with IVC therapy
  • Importance of discussing vitamin C infusions as part of a comprehensive treatment plan with an oncologist, rather than using them as an alternative to conventional cancer therapies
  • Need for careful patient selection and monitoring to minimize adverse effects and ensure safe use of vitamin C infusions, if considered at all, based on individual patient circumstances and under close medical supervision, as suggested by 1.

From the Research

Vitamin C Infusion in Cancer Patients

  • The use of vitamin C infusion in patients with malignancy has been studied in various research papers 2, 3, 4, 5, 6.
  • According to a 2021 study, vitamin C was applied intravenously or orally to patients with various malignant diseases, and the results showed either no effect or a positive trend, although this was rarely statistically proven in group comparisons 2.
  • A 2022 review article suggests that high doses of vitamin C administered intravenously may improve patients' quality of life, particularly for terminal cancer patients, by reducing chemotherapy-related side effects 3.
  • Preclinical studies have shown that high-dose vitamin C can have antitumor effects, and its mechanisms of action include pro-oxidant effects, modulation of TET enzymes, and alteration of the DNA damage response 4.
  • A 2006 case study reported three cases of advanced cancers where patients had unexpectedly long survival times after receiving high-dose intravenous vitamin C therapy, suggesting that the role of high-dose intravenous vitamin C therapy in cancer treatment should be reassessed 5.
  • A 2018 review article provides a rational approach to the use of intravenous vitamin C in cancer care, suggesting that it can be a safe supportive intervention to decrease inflammation and improve symptoms related to antioxidant deficiency and disease processes 6.

Key Findings

  • Intravenous administration of vitamin C may be more effective than oral intake in patients with malignancies 2, 5.
  • High doses of vitamin C can have antitumor effects and improve patients' quality of life 3, 4.
  • The use of intravenous vitamin C is generally considered safe, with few side effects reported 2, 6.
  • Further clinical trials are needed to collect stronger evidence of the role of vitamin C in supportive cancer treatment 3, 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Intravenously administered vitamin C as cancer therapy: three cases.

CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne, 2006

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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