For decades, vitamin C has had the reputation as the go-to vitamin to support the immune system. Now, many people are turning to high-dose vitamin C as a treatment, especially for chronic diseases and cancer.

Is this something that you should consider? Let’s find out.

What Does High-Dose Vitamin C Do?

As its name suggests, high-dose vitamin C, or HDIVC, is a treatment involving very high doses of vitamin C, usually administered intravenously. Doses are generally above 1 gram per day, often around 10 to 15 grams. Compare that to the RDA of 75 milligrams for non-pregnant, non-lactating adult women and 90 mg for adult men, based on the levels set by the Institute of Medicine Food and Nutrition Board.

The theory behind this treatment is that the intravenous administration bypasses the digestive system, leading to higher levels in the blood, which makes it easier to benefit from vitamin C. In lower doses vitamin C is an antioxidant, but at high doses, vitamin C turns into a pro-oxidant.  This explains the theory of why it may be beneficial for chronic disease and cancer.

What Conditions Can It Treat?

According to a study published in PLoS One, HDIVC has been used to help:

  • Fatigue
  • Infections, such as the flu or common cold
  • Cancer
  • Scurvy, or vitamin C deficiency

One of the most studied conditions treated with HDIVC is cancer, with research dating to the 1970s and the work of Dr. Linus Pauling, according to the National Cancer Institute.

Benefits of High Dose Vitamin C

Vitamin C is an important antioxidant vitamin that plays a role in many different body processes, including making collagen, healing wounds and repairing the body. Large doses of vitamin C ensure that your body has sufficient levels of the essential vitamin and becomes a pro-oxidant which may combat unhealthy cells This might enhance:

  • Bone and tissue health
  • Antioxidant status
  • Immune health
  • Resilience
  • Reduced inflammation

The Biochemistry and Physiology

Radical oxygen species (ROS) and other charged particles known as free radicals are normal byproducts of reactions in the body that cause damage when in excess. Antioxidants, such as vitamin C, mitigate these charged molecules – rendering them harmless.

Although antioxidants protect against oxidative stress, too many can lead to a pro-oxidant state, meaning they actually create free radicals. This might not be all bad; in fact, it might be why high doses of vitamin C kill cancer cells.

According to a study published in Redox Biology, high dose vitamin C works specifically on cancer cells because a common ROS, hydrogen peroxide, is a byproduct of the breaking down of excess levels of vitamin C. Tumor cells are less able to handle the hydrogen peroxide, so they are more likely to die.

Mitigating Herxheimer Reactions

Vitamin C might also help mitigate a Herxheimer reaction. This occurs after a treatment kills viruses or bacteria, but the byproducts trigger an exacerbation of symptoms. High-doses of vitamin C and other antioxidants mitigate this reaction by reducing oxidative stress and the associated inflammation, relieving the symptoms.


I was diagnosed with testicular cancer and I did a tremendous amount of research on alternative therapies and I came across high dose vitamin C. In addition to my conventional treatment, I was adjunctively treated with high dose vitamin C. The vitamin C allowed me to get through treatment – provided me more energy throughout the day. Happy to say that I am cancer free now & feeling great! Thanks to my medical team including my naturopathic doctors at LIVV!

Marco S.

Side Effects

In one human safety trial published in Cancer Cell, the only side effects mentioned were dry mouth and rare but brief high blood pressure episodes. Consuming high quantities of vitamin C orally can lead to diarrhea, but this generally does not occur with IV doses. A small percentage of people have a higher risk of side effects, including those:

  • At risk of hemochromatosis, or excess iron levels
  • With G-6-PD deficiency
  • With certain kidney disorders
  • Taking certain drugs

What Do I Need To Do Before Being a Candidate For HDIVC?

Not everyone is a candidate for HDIVC. Consider whether you:

  • Have any of the above risk factors
  • G6PD deficiency
  • Take medication for which vitamin C is a known disruptor, such as some cancer medications, statins and Warfarin
  • Have a condition for which vitamin C might benefit
  • Experience symptoms of vitamin C deficiency

If you feel that you are a candidate, then discuss it with your doctor before heading to a facility offering high-dose vitamin C treatment. It is important to note that the Food and Drug Administration (FDA) has yet to approve its use to treat any medical condition, including cancer.

Dr. Jason Phan NMD – LIVV Natural Health | Naturopathic Medical Doctor specializing in IV Vitamin Therapy, PRP (platelet rich plasma)/Regenerative Medicine, Lifestyle Medicine, and Optimal Living.