Vitamin C and Cancer: The Hidden Truth

What if there was a safe and effective way to lengthen the lives of terminal cancer patients who had exhausted their conventional treatment options?

There is.  Nearly 80% of alternative clinics use large doses of intravenous vitamin C (ascorbate) for a variety of health conditions including cancer. (1)  And they do so because studies in the late 1970s showed that this practice extended the lives of terminal cancer patients by an average of 200-300 days.  In 10% of cases, patients deemed "hopeless" and "utterly untreatable" lived at least several more years.

The practice dates back to the 1940s, when Dr. Klenner used it to treat a variety of infectious diseases.  And it is now making inroads in integrative oncology clinics after being neglected for nearly a half century.

Cancer patients who are regularly treated with ascorbate experience fewer side effects such as fatigue, nausea, pain, vomiting, and appetite loss.  They also have better performance status, better quality of life, and longer survival. (2-4) 

The mainstream oncology community is still largely opposed to ascorbate, however.  There are a variety of reasons, but chief among them are the belief that alternative therapies will:

  • steer people away from conventional treatment.
  • interfere with chemotherapy because ascorbate is an anti-oxidant. 

The problem with this line of reasoning is that pharmacological doses of this vitamin are not anti-oxidant: they are pro-oxidant.  Second, it may offer lengthened survival to terminal cancer patients that have exhausted their conventional options.

Let’s look at all of this in more detail.

Evidence for Using High-Dose IV Vitamin C 

A landmark study was published in 1976 by Linus Pauling (Nobel Prize winner in chemistry, 1959) and his colleague Ewan Cameron.  This study demonstrated that 10 g. intravenous ascorbate per day for 10 days, followed by 10 g. oral ascorbate per day thereafter, resulted in a two- to seven-fold increase in survival in 100 terminal cancer patients, depending on the type of cancer. (5)

Each of these 100 patients was considered terminal: untreatable and “totally hopeless” by at least two physicians. 

In this 1976 study, survival time across all cancers was more than 210 days for those treated with vitamin C, compared to only 50 days for the untreated matched controls.  

Because the result was received with skepticism, they published a new study in 1978, in which they discarded the original 1000 control patients from the study and re-analyzed the original treatment group of 100 patients with newly selected controls.  Ironically, the mean survival time in the treated group was found to be even greater this time.  

Those treated with vitamin C lived 300 days more than the matched controls. (6)

This seems like powerful evidence in favor of using high-dose intravenous ascorbate.  But the doses are huge: more than 100 times the FDA’s Recommended Daily Allowance from food.  

What happened? 

This created a storm of controversy in the scientific community.  Shortly thereafter, two more studies were conducted at the Mayo Clinic attempting to replicate these results. (7, 8)  Vitamin C was dismissed as a cancer treatment.  Why?

The Mayo studies found no difference in symptoms or survival between treatment and control groups using 10 g. ascorbate for treatment.  However, there is one very crucial difference between these two sets of studies.  The cancer patients in the Mayo Clinic studies did not get the preliminary 10 days of intravenous treatments: they received only oral ascorbate.

This is a critical distinction. (9, 10)    Studies performed by Mark Levine and colleagues at the National Institutes of Health over the past several decades have shown that ascorbate administered intravenously causes plasma levels up to 100 times higher than that achievable by the same dose administered by mouth! (11-15)      

New studies also demonstrate that at such high doses, ascorbate does not act as an antioxidant.  Instead, it does the opposite: it acts a pro-drug to deliver hydrogen peroxide to tissues, and cancer cells are especially sensitive to it in comparison to healthy cells. 

Let’s look at a bit more additional evidence that ascorbate is an effective cancer treatment.

More Detective Work: Vitamin C Levels and Survival

  • Pauling and Cameron observed that cancer patients are significantly depleted of ascorbate, and this substantially increases their requirements. (5)  
  • Cancer patients who are deficient in ascorbate prior to therapy achieve lower plasma levels post-infusion. (16)
  • When a patient has higher inflammation or tumor burdens (as measured by CRP or tumor antigen levels) they will achieve lower plasma levels after receiving intravenous ascorbate. (16)
  • Patients with metastatic tumors also achieve lower post-infusion plasma levels of ascorbate than patients with localized tumors. (16)
  • Higher tumor ascorbate levels are correlated to increased length of survival in colorectal cancer patients. (17)

In plain terms, the greater the burden of cancer, infection, or toxins, the more quickly one will deplete stores of ascorbate. 

One of the foremost experts in clinical applications of ascorbate, Dr. Thomas Levy, has noted that he must use more ascorbate today to achieve the same effect in patients when compared to the amounts Dr. Klenner used in the 1940s.  He believes this is because people are more nutritionally depleted and exposed to toxins in the modern world, which rapidly eliminates the body's supplies. (18) 

When these burdens are high, ascorbate is constantly being used to neutralize toxins through the donation of electrons.  Cameron has also pointed out that the frequency of dosing is important. (19)  The Cameron/Pauling 1976 study patients used ascorbate on a daily basis. 

What about the idea that ascorbate counteracts chemotherapy?  This is a common assertion of oncologists, leading them to go so far as to tell patients even to avoid blueberries.

One high profile clinical study carried out by Levine and colleagues showed that the combination of IV ascorbate with two chemotherapies inhibited ovarian cancer in mice more than the chemotherapy alone.  The ascorbate also reduced chemotherapy-associated toxicity in human patients with ovarian cancer, and it increased the amount of time until they relapsed back into cancer. (13) Similar results have been seen in pancreatic cancer patients. (20)

Although ascorbate usually simply slows the growth of the cancer, in some rare cases remission can occur.  Pauling and Cameron noted that around 10% of the terminal cancer patients treated with ascorbate lived an unusually long time of several years or more.

Why Isn’t Vitamin C Already Mainstream? 

It’s pretty simple.  Administering high doses of vitamins now has a tainted association with “alternative medicine” due to its supposed de-bunking by the Mayo Clinic.  Not even a chemistry Nobel Prize Winner like Linus Pauling can escape accusations of quackery (just do a brief web search for his name and Vitamin C).

It seems a bit unbelievable to the medical profession that something simple and non-technological could work so well at slowing the growth of cancer.  That’s because they were hamstrung by the belief that large doses of ascorbate are anti-oxidant rather than a pro-drug that creates hydrogen peroxide with selective toxicity.  This is a common thread in much medical history.  Doctors resisted handwashing for decades in the 1800s because they didn't understand how it works.

Second, in the 1960s, the FDA started demanding that drugs not only be tested for safety, but also efficacy.  This is a major hurdle toward adoption of any new therapy: it can cost drug companies hundreds of millions of dollars just to conduct the studies that prove that the drugs work.  

There’s no financial incentive to pour this type of research into a vitamin.  There’s nothing to be patented and thus, no financial reward to offset the huge amounts of money required to fund more studies. Studies will thus remain small and limited in number. (21) 

How Does High Dose IV Vitamin C Work?

Even a genius like Linus Pauling did not understand the mechanisms for why ascorbate was effective against cancer.  More than four decades later, we're still discovering more mechanisms of action, too.  I list the known mechanisms below.

Hydrogen Peroxide Generation 

Large amounts of ascorbate in the bloodstream result in the creation of hydrogen peroxide through Fenton reactions when ascorbate encounters metal ions.  These reactions occur close to cell membranes. (22-24)

Because these reactions are localized in the extracellular space, and because cancer cells are much more sensitive to hydrogen peroxide than normal cells, this creates oxidative stress in close proximity to cancer cells that they can’t handle nearly as well as normal cells. (13, 15, 20)

Cancer cells produce superoxide in greater than normal amounts, which can interact with the hydrogen peroxide produced via ascorbate creating deadly hydroxyl radicals that also disproportionately affect them. (25, 26) 

Other mechanisms of action include:

  • disrupting the cell cycle of division (27)
  • causing apoptosis (a type of programmed cell death) (27)
  • suppressing angiogenesis (development of a blood supply to a tumor) (27)
  • oxidizing glutathione in cancer cells, making them more susceptible to oxidative damage (13)
  • disrupting disulfide bond formation in proteins (13)
  • depleting cellular ATP (the cell’s source of energy) in the cancer cell (13, 26, 27)
  • inducing DNA and protein damage in the cancer cell through hydroxylation and demethylation (13, 26) 
  • increasing immunity (26)

As you can see, there are many biochemical mechanisms for how ascorbate fights cancer.  It is difficult to obtain so many different effects with drugs that have single, defined mechanisms of actions.  

Hindsight is 20/20.  Even though Linus Pauling didn’t understand why ascorbate worked, modern science is piecing the mechanisms together today, over 40 years later.  And as the research continues to unfold, it’s clear that high-dose ascorbate can be safely added to most conventional first line cancer treatments. (27)


How to Use Vitamin C

If I had cancer, I would choose a similar protocol to that recommended by Dr. Thomas Levy, Vitamin C expert. (28)   

  • Daily or several times weekly intravenous vitamin C of 50-100g
  • 5-10 g. (5000 mg.) daily liposomal vitamin C by mouth

That's it.

You can find a medical practitioner in your area that offers intravenous ascorbate just by doing a web search of “IV Vitamin C” with your geographic area.  

I cannot stress the importance of IVs enough.  I see a lot of health bloggers simply recommending large intakes of vitamin C from supplements and food.  The Mayo Clinic studies showed that this doesn't work!

For all of the reasons I’ve explained, it’s impossible to achieve the blood levels required to fight cancer with ordinary ascorbate by mouth, even at large ingested doses.  It simply will not pass over into the bloodstream because absorption is tightly regulated by the digestive system.  This is why high doses of ascorbate cause diarrhea: it will simply be excreted before you can absorb it.

For various reasons, IV ascorbate may be unavailable to many people.  What if you live in an extremely rural area or a foreign country?  What if you cannot find a practitioner to administer IV Vitamin C at all? 

If I was in such a situation, I would rely on liposomal vitamin C by mouth.  Even for cancer patients taking IV Vitamin C, Dr. Levy believes that taking daily liposomal vitamin C is a good idea.    

I recommend the Lipospheric Vitamin C from Livon Labs for several reasons:

  • it is the brand recommended by an expert physician in ascorbate, Dr. Levy
  • it is the oldest company in the business and not a “copycat” brand
  • it is only a few cents more expensive per dose than cheaper brands which may not have developed the technology to encapsulate the vitamin as well

Why Liposomal Vitamin C?  

Liposomal vitamin C is a relatively new technological development.  It is ascorbate loaded into a bubble of phospholipids, which are the same molecules your cell membranes are made of.  Very much like intravenous ascorbate, the liposomes can bypass normal digestive barriers in order to deliver it directly to cells or organelles within cells!  (18) 

There are 40 years of research behind the liposomal delivery of drugs.  There is still much more research for intravenous ascorbate than liposomal ascorbate, but Dr. Levy has stated that in patients with viral infections, he has observed that a 5 g. daily dose of liposomal vitamin C is equivalent to a 50 g. intravenous dose. (18)  So there's reason to believe that it could work for cancer also.

In one study, when ascorbate was delivered to cancer cells along with chemotherapy in a liposome, the chemotherapy was more effective than it was on its own!  Ascorbate also protected cells from the stress of the chemotherapy. (29, 30)  That's the exact same result from the human studies of ovarian and pancreatic cancer using IV vitamin C.  

I do not recommend making liposomal vitamin C at home, although there are many recipes online for how to do so.  Sonication and blending will not result in the levels of encapsulation that are possible in a professional lab.


Always discuss any supplementation or alternative treatment regimen with your physician. To aid you in this regard, I’ve provided a list of chemotherapies and supplements that ascorbate may interact with synergistically or antagonistically and a list of medical conditions which would prevent you from using intravenous ascorbate.  


Interactions Between Ascorbate and Chemotherapy/Radiation 

Syngergistic with ascorbate: docetaxel, epirubicin, doxorubicin, cisplatin, paclitaxel, 5-fluorouracil,  tyrphostin.gemcitabine. 

Antagonistic with ascorbate: imatinib, etoposide, taurolidine, paclitaxel, -α-tocopherol ( a form of vitamin E), bortezomib. (Note that another study has found that vitamin C acts synergistically with paclitaxel.)

No effect: oxaliplatin, vinorelbin

Ascorbate is a potential radio sensitizer of glioblastoma and leukemia, but no in vivo studies have been conducted. (27)

Supplements to Avoid When Using IV Ascorbate

Both glutathione and N-acetylcysteine should most likely be avoided in combination with intravenous ascorbate, as they will interfere with its mechanisms of action. (27)


With proper patient screening, intravenous ascorbate is extremely safe and has minimal risk. (1, 3)  However, the following conditions may prevent you from using intravenous ascorbate: renal insufficiency, renal failure, undergoing dialysis, history of oxalate kidney stones, iron overload, glucose-6-phosphate dehydrogenase deficiency. (1, 3, 14) 

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1) Padayatty, S. J., Sun, A. Y., Chen, Q., Espey, M. G., Drisko, J., & Levine, M. (2010). Vitamin C: Intravenous Use by Complementary and Alternative Medicine Practitioners and Adverse Effects. PLoS ONE, 5(7), e11414.

2)  Fritz H, Flower G, Weeks L, Cooley K, Callachan M, McGowan J, Skidmore B, Kirchner L, Seely D. 2014. Intravenous Vitamin C and Cancer: A Systematic Review.  Integr Cancer Ther. 13(4):280-300. doi: 10.1177/1534735414534463

3) Violet, P.-C., & Levine, M. (2017). Pharmacologic Ascorbate in Myeloma Treatment: Doses Matter. EBioMedicine, 18, 9–10.

4)  Carr, A. C., Vissers, M. C. M., & Cook, J. S. (2014). The Effect of Intravenous Vitamin C on Cancer- and Chemotherapy-Related Fatigue and Quality of Life. Frontiers in Oncology, 4, 283.

5) Cameron E, Pauling L. 1976. Supplemental ascorbate in the supportive treatment of cancer: prolongation of survival times in terminal human cancer. Proc Natl Acad Sci U S A.73:3685-3689.

6) Cameron E, Pauling L. 1978. Supplemental ascorbate in the supportive treatment of cancer: Reevaluation of prolongation of survival times in terminal human cancer.  Proc Natl Acad Sci U S A. 75(9): 4538–4542.

7)  Creagan ET, Moertel CG, O'Fallon JR, et al. Failure of high-dose vitamin C (ascorbic acid) therapy to benefit patients with advanced cancer. A controlled trial. N Engl J Med 1979;301:687-90.

8)  Moertel CG, Fleming TR, Creagan ET, et al. High-dose vitamin C versus placebo in the treatment of patients with advanced cancer who have had no prior chemotherapy. A randomized double-blind comparison. N Engl J Med 1985;312:137-41.

9)  Levine, M., Espey, M. G., & Chen, Q. (2009). Losing and finding a way at C: New promise for pharmacologic ascorbate in cancer treatment. Free Radical Biology & Medicine, 47(1), 27–29.

10)  Padayatty SJ, Levine M. 2000. Reevaluation of ascorbate in cancer treatment: emerging evidence, open minds and serendipity. J Am Coll Nutr. 19(4):423-5.

11)  Levine, M., Padayatty, S. J., & Espey, M. G. (2011). Vitamin C: A Concentration-Function Approach Yields Pharmacology and Therapeutic Discoveries. Advances in Nutrition, 2(2), 78–88.

12)  Cieslak, J. A., & Cullen, J. J. (2015). Treatment of Pancreatic Cancer with Pharmacological Ascorbate. Current Pharmaceutical Biotechnology, 16(9), 759–770.

13)  Ma Y, Chapman J, Levine M, Polireddy K, Drisko J, Chen Q. Sci Transl Med. 2014. High-dose parenteral ascorbate enhanced chemosensitivity of ovarian cancer and reduced toxicity of chemotherapy. 6(222):222ra18. doi: 10.1126/scitranslmed.3007154.

14)  Padayatty, S. J., Riordan, H. D., Hewitt, S. M., Katz, A., Hoffer, L. J., & Levine, M. (2006). Intravenously administered vitamin C as cancer therapy: three cases. CMAJ : Canadian Medical Association Journal, 174(7), 937–942.

15)  Park, S. (2013). The Effects of High Concentrations of Vitamin C on Cancer Cells. Nutrients, 5(9), 3496–3505.

16)  Mikirova, N., Casciari, J., Riordan, N., & Hunninghake, R. (2013). Clinical experience with intravenous administration of ascorbic acid: achievable levels in blood for different states of inflammation and disease in cancer patients. Journal of Translational Medicine, 11, 191.

17)  Kuiper, C., Dachs, G. U., Munn, D., Currie, M. J., Robinson, B. A., Pearson, J. F., & Vissers, M. C. M. (2014). Increased Tumor Ascorbate is Associated with Extended Disease-Free Survival and Decreased Hypoxia-Inducible Factor-1 Activation in Human Colorectal Cancer. Frontiers in Oncology, 4, 10.


19)  Cameron E. 1991. Med Hypotheses. Protocol for the use of vitamin C in the treatment of cancer. 36(3):190-4.

20)  Cieslak, J. A., & Cullen, J. J. (2015). Treatment of Pancreatic Cancer with Pharmacological Ascorbate. Current Pharmaceutical Biotechnology, 16(9), 759–770.

21)  Hoffer, L. J., Robitaille, L., Zakarian, R., Melnychuk, D., Kavan, P., Agulnik, J., … Miller, W. H. (2015). High-Dose Intravenous Vitamin C Combined with Cytotoxic Chemotherapy in Patients with Advanced Cancer: A Phase I-II Clinical Trial. PLoS ONE, 10(4), e0120228.

22)  Levine, M., Padayatty, S. J., & Espey, M. G. (2011). Vitamin C: A Concentration-Function Approach Yields Pharmacology and Therapeutic Discoveries. Advances in Nutrition, 2(2), 78–88.

23)  Levine M, Daruwala RC, Park JB, Rumsey SC, Wang Y. 1998. Does vitamin C have a pro-oxidant effect? Nature. 17;395(6699):231; author reply 232.

24)  Chen, Q., Espey, M. G., Krishna, M. C., Mitchell, J. B., Corpe, C. P., Buettner, G. R., … Levine, M. (2005). Pharmacologic ascorbic acid concentrations selectively kill cancer cells: Action as a pro-drug to deliver hydrogen peroxide to tissues. Proceedings of the National Academy of Sciences of the United States of America, 102(38), 13604–13609.

25)  McCarty, M. F., & Contreras, F. (2014). Increasing Superoxide Production and the Labile Iron Pool in Tumor Cells may Sensitize Them to Extracellular Ascorbate. Frontiers in Oncology, 4, 249.

26)  Ploumakis A, Coleman ML. 2015. OH, the Places You'll Go! Hydroxylation, Gene Expression, and Cancer. Mol Cell. 4;58(5):729-41. doi: 10.1016/j.molcel.2015.05.026.

27)  Parrow, N. L., Leshin, J. A., & Levine, M. (2013). Parenteral Ascorbate As a Cancer Therapeutic: A Reassessment Based on Pharmacokinetics. Antioxidants & Redox Signaling, 19(17), 2141–2156.


29)  Yang Y, Lu X, Liu Q, Dai Y, Zhu X, Wen Y, Xu J, Lu Y, Zhao D, Chen X, Li N. 2017. Palmitoyl ascorbate and doxorubicin co-encapsulated liposome for synergistic anticancer therapy. Eur J Pharm Sci. 105:219-229. doi: 10.1016/j.ejps.2017.05.038. Epub 2017 May 17.

30)  Davis, J. L., Paris, H. L., Beals, J. W., Binns, S. E., Giordano, G. R., Scalzo, R. L., … Bell, C. (2016). Liposomal-encapsulated Ascorbic Acid: Influence on Vitamin C Bioavailability and Capacity to Protect Against Ischemia–Reperfusion Injury. Nutrition and Metabolic Insights, 9, 25–30.


The ideas in this website are not intended as a substitute for the advice of a trained health professional. All matters regarding your health require medical supervision. Consult your physician and/or health care professional before adopting any nutritional, exercise, or medical protocol. Consult your physician about any condition that may require diagnosis or medical attention. Statements regarding certain products and services represent the views of the author alone, and do not constitute a recommendation or endorsement or any product or service.