The short answer
This page checks the claim that high-dose IV vitamin C cures cancer, using NCI sources. It is general education, not individual medical advice.
FDA has not approved IV vitamin C as a treatment for cancer.
Study results are mixed. Some found better quality of life; others found no effect on tumors.
In people with a history of kidney disease, kidney failure has been reported after IV vitamin C.
People with G6PD deficiency should not get high doses. High doses are not recommended with hemochromatosis.
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The fact: FDA has not approved IV vitamin C as a treatment for cancer. The claim being checked is that high-dose vitamin C given into a vein cures cancer. The evidence does not show that.
What IV vitamin C is
Vitamin C is a nutrient. Given IV (through a vein), it reaches much higher levels in the blood than when taken by mouth, according to NCI.
What studies in people show
NCI describes mixed results. In one study, people with cancer who got IV vitamin C had better quality of life and fewer cancer-related side effects. In another, IV vitamin C did not lower PSA levels or stop tumors from growing. Mixed results in early studies are not proof of a cure.
Known risks
NCI says IV vitamin C is generally well tolerated, but:
- In people with a history of kidney disease, kidney failure has been reported after treatment with IV vitamin C.
- People with G6PD deficiency should not get high doses, because it may cause hemolysis (red blood cells breaking apart).
- High doses are not recommended for people with hemochromatosis, because vitamin C may increase iron absorption.
What to do
Talk with your care team before trying IV vitamin C or any supplement. Do not delay or replace proven treatment. If a symptom is new or lasts, get it checked. In an emergency, call 911. For a possible poisoning or overdose, call Poison Control at 1-800-222-1222.
Common questions
Is IV vitamin C approved to treat cancer?
No. NCI states that FDA has not approved the use of IV vitamin C as a treatment for cancer.
What have studies in people found?
Results are mixed. NCI describes one study where people who got IV vitamin C had better quality of life and fewer cancer-related side effects, and another where it did not lower PSA levels or stop tumors from growing.
Is it safe?
NCI says it is generally well tolerated, but kidney failure has been reported. People with G6PD deficiency (an inherited disorder) may have red blood cells break down, and people with hemochromatosis (too much iron) should not get high doses.
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Sources last checked: 2026-10-02 what this meansLast updated: 2026-09-27Next planned review: 2027-03-27
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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