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Studies of IV Vitamin C

Posted by Geoff Beaty on 23 July 2021
Studies of IV Vitamin C

Vitamin C is a nutrient found in food and dietary supplements. It is an antioxidant and also plays a key role in making collagen. 

High-dose vitamin C may be taken by mouth or given by an intravenous (IV) infusion (through a vein into the bloodstream). When taken by IV infusion, vitamin C can reach higher levels in the blood than when the same amount is taken by mouth.

Some studies of IV high-dose vitamin C in patients with cancer have shown improved quality of life, as well as fewer side effects. 

In general, high-dose vitamin C given by IV has caused very few side effects in clinical trials. However, IV vitamin C may cause serious side effects in patients with kidney disease, G6PD deficiency, or hemochromatosis.

The evidence:

In a small study of 14 patients with advanced pancreatic cancer, IV vitamin C was given along with chemotherapy and targeted therapy (erlotinib). Five patients did not complete the treatment because the tumour continued to grow during treatment. The nine patients who completed the treatment had stable disease as shown by imaging studies. Patients had very few side effects from the vitamin C treatment.

In another small study of 9 patients with advanced pancreatic cancer, patients were given chemotherapy once a week for 3 weeks along with IV vitamin C twice a week for 4 weeks during each treatment cycle. The disease did not progress over an average of 6 months in these patients. No serious side effects were reported with the combined treatment.

In a 2014 study of 27 patients with advanced ovarian cancer, chemotherapy alone was compared with chemotherapy and IV vitamin C. IV vitamin C was given during chemotherapy and for 6 months after chemotherapy ended. Patients who received IV vitamin C had fewer side effects from the chemotherapy.

Patients with non-small cell lung cancer or glioblastoma multiforme in two pilot trials were given standard therapy plus IV vitamin C. Patients had better overall survival and fewer side effects compared to the control groups.

More studies of combining IV high-dose vitamin C with other drugs are being done. These include a number of clinical trials combining IV vitamin C with arsenic trioxide, showing mixed results.

Have any side effects or risks been reported from high-dose vitamin C?

IV high-dose vitamin C has caused very few side effects in clinical trials. However, high-dose vitamin C may be harmful in patients with certain risk factors.

In patients with a history of kidney disease, kidney failure has been reported after treatment with high-dose vitamin C. Patients who are likely to develop kidney stones should not be treated with high-dose vitamin C.

One study reported too much fluid in the body (fluid overload) related to IV vitamin C. This may have been caused by the IV delivery method and not the vitamin C.

Case reports have shown that patients with an inherited disorder called G6PD deficiency should not be given high doses of vitamin C, because it may cause hemolysis (a condition in which red blood cells are destroyed).

Because vitamin C may make iron more easily absorbed and used by the body, high doses of vitamin C are not recommended for patients with hemochromatosis (a condition in which the body takes up and stores more iron than it needs).


Author:Geoff Beaty
Tags:NewsEvidence Based ResearchMost PopularCancerIntravenous Vitamin C


  • The Institute for Functional Medicine
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