What Is High Dose Vitamin C?
- July 15, 2024
- Written by : Rebecca LaMarca, MSN, APN-BC, CNS
Vitamin C, also known as ascorbic acid, is a nutrient and antioxidant primarily found in fruits and vegetables like oranges, grapefruit, kiwi, peppers and broccoli. Vitamin C is key in producing collagen and helps prevent free radical damage from occurring.1
It’s recommended that women get 75 mg of vitamin C a day and men get 90 mg per day, according to the Mayo Clinic,2 which can generally be achieved through a healthy diet. But using high dose vitamin C IV therapy has become more common in helping to treat fatigue, infections and cancer.3

High dose vitamin C benefits
Vitamin C provides many benefits, including help with iron absorption and immune system support. Beyond those well-known benefits, studies show that vitamin C also may help reduce the risk of chronic illness, manage high blood pressure and lower risk of heart disease.
Vitamin C is water soluble, which means it dissolves in water, so under normal circumstances, getting more than the daily recommended value doesn’t have added benefits. Excess water-soluble vitamins leave your body through urine, as opposed to excess fat-soluble vitamins, which get stored in the body.4
While the average person might not experience benefits from using high dose vitamin C, the continued studies on its use for cancer patients have been particularly intriguing.
Vitamin C therapy for cancer
Some studies have shown that high-dose vitamin C infusions can improve the quality of life and reduce side effects of cancer treatment. For example, the National Cancer Institute published “Intravenous Vitamin C” finding that patients with advanced cancer who received high-dose vitamin C infusions had a better quality of life and fewer side effects than those who did not receive the infusions.
Other studies have shown that high-dose vitamin C infusions can shrink tumors or slow their growth. For example, a study published in the journal “Intravenous High-Dose Vitamin C in Cancer Therapy” found that high-dose vitamin C infusions could shrink tumors in mice with pancreatic cancer.
However, despite all these positive studies, the use of high dose vitamin C to treat cancer has been controversial. The FDA hasn’t approved high dose vitamin C therapy for cancer, but according to an article by Lewis Cantley of Weill Cornell Medicine and Jihye Yun of Baylor College of Medicine, there’s been an increase in phase I and II clinical trials on the efficacy of high dose vitamin C therapy in treating cancer patients either in conjunction with their regimen or as a monotherapy.5
“Virtually all studies show improved quality of life for cancer patients by minimizing pain and protecting normal tissues from toxicity caused by chemotherapy,” Cantley and Yun wrote in 2020. “Additionally, vitamin C showed synergistic effects when combined with radiation and standard chemotherapies.”
It is important to note that high-dose vitamin C infusions can have side effects, such as nausea, vomiting, and diarrhea. These side effects are usually mild and go away on their own.
Overall, the research on high-dose vitamin C infusions for cancer is mixed. More research is needed to determine whether this treatment is effective.Patients should consult with their oncologist before pairing high dose vitamin C IV therapy with radiation or chemotherapy. Consultation with our certified functional medicine nurse practitioner who is trained under Dr. Winters can be done for all inquiring patients.
REFERENCES
- Intravenous vitamin C. (2024, May 28). Cancer.gov. https://frederick.cancer.gov/news/intravenous-high-dose-vitamin-c-cancer-therapy
- Too much vitamin C: Is it harmful? (2022, April 28). Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/vitamin-c/faq-20058030
- Intravenous vitamin C (PDQ®). (2024, April 5). Cancer.gov. https://www.cancer.gov/about-cancer/treatment/cam/hp/vitamin-c-pdq#section_3.9
- Chambial, S., Dwivedi, S., Shukla, K. K., John, P. J., & Sharma, P. (2013). Vitamin C in Disease Prevention and Cure: An Overview. Indian Journal of Clinical Biochemistry, 28(4), 314–328. https://doi.org/10.1007/s12291-013-0375-3
- Intravenous High-Dose vitamin C in cancer therapy. (2020, January 24). Cancer.gov. https://frederick.cancer.gov/news/intravenous-high-dose-vitamin-c-cancer-therapy



