High-dose intravenous vitamin C, a promising multi-targeting agent in the treatment of cancer
Vitamin C in IV Therapy for Cancer
In recent years, high-dose intravenous vitamin C (IVC) has attracted attention as a complementary approach in oncology. Unlike oral supplements, IV administration allows vitamin C to reach therapeutic levels in the bloodstream — concentrations that can’t be achieved through diet or supplementation.
At these high levels, vitamin C appears to act not just as an antioxidant, but also as a pro-oxidant in cancer cells, leading to cellular damage and potentially supporting the effectiveness of standard cancer treatments.
How Does It Work?
High-dose IV vitamin C appears to support cancer care through multiple mechanisms:
- Pro-oxidant effect in cancer cells: At therapeutic doses, vitamin C generates hydrogen peroxide in the tumor environment. Cancer cells, which are more vulnerable to oxidative stress than healthy cells, may be damaged or killed by this reaction.
- Enhancing the effects of chemotherapy or targeted therapy: Vitamin C may make cancer cells more sensitive to conventional treatments, potentially improving their efficacy when used simultaneously.
- Supporting the body during treatment: Some early studies suggest that IVC may help maintain quality of life, reduce treatment-related side effects, and protect normal tissues during chemotherapy or radiation.
Clinical Studies: What Does the Research Say?
Although more large-scale trials are needed, several early clinical studies have shown promising results when high-dose IVC is used alongside standard cancer therapies:
Pancreatic Cancer
- A study combining IVC with chemotherapy drugs gemcitabine and erlotinib in stage IV pancreatic cancer found that 8 out of 9 patients experienced tumor shrinkage after just 8 weeks of treatment.
- Another trial using IVC with gemcitabine alone saw patients maintain or improve their performance status, with a median survival of 13 months — a meaningful outcome in this difficult-to-treat cancer.
Colorectal and Gastric Cancer
- In a study involving advanced colorectal and gastric cancer patients, IVC was added to standard chemotherapy (FOLFOX or FOLFIRI, with or without bevacizumab).
- Out of 24 patients, 58% showed partial tumour shrinkage, and 37.5% had stable disease — for a disease control rate of 95.8%.
- Notably, both wild-type and mutant RAS/BRAF tumours responded similarly, suggesting IVC may help across different genetic cancer types.
Lung Cancer with Non-Drug Therapy
- A randomized trial in advanced non-small cell lung cancer compared IVC plus modulated electrohyperthermia (mEHT) with best supportive care.
- The IVC/mEHT group had significantly improved survival and quality of life — with median survival of 9.4 months vs 5.6 months in the control group.
Safety Profile
Across these studies, high-dose IVC was generally well tolerated. The adverse effects reported were mostly consistent with those caused by chemotherapy itself. Importantly, none were conclusively linked to vitamin C. However, patients with certain conditions like kidney impairment or G6PD deficiency should be screened carefully before receiving high-dose IVC.
High-dose IV vitamin C is showing increasing promise as a complementary therapy in cancer care. By achieving therapeutic levels in the bloodstream, it may damage cancer cells, enhance the effectiveness of other treatments, and support patients’ overall well-being. Clinical studies have reported tumor shrinkage, improved survival outcomes, and maintained quality of life when IVC is used alongside standard therapies — all with a generally favorable safety profile.
While more research is still needed, especially large-scale trials, high-dose IVC continues to offer hope as a non-toxic and accessible adjunct in integrative oncology.
Interested in Learning More?
If you or someone you love is navigating cancer care and curious about the role of IV vitamin C, please contact us and we can set up a complimentary discovery call to explain how our Naturopathic Doctors can help determine whether this approach is appropriate and safe for your specific situation.
Read more about high dose vitamin C therapy here.
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Study: High-dose intravenous vitamin C, a promising multi-targeting agent in the treatment of cancer – PMC (PMID: 34717701)
