Is hydrogen peroxide an effective cancer treatment?

If you’re researching natural cancer treatments, chances are hydrogen peroxide is on your radar. H2O2 is not, however, a panacea; it is not a solution or remedy for diseases, including cancer.

But for head and neck cancer patients, a clinical trial is underway that could prove to be a game-changer.

A mild antiseptic, hydrogen peroxide can prevent infection of minor cuts, scrapes, and burns. H2O2 has many applications – rocket fuel (!), cosmetics, and cleaning products – but it is not recognized as a health supplement by the U.S. Food and Drug Administration.

The FDA classifies hydrogen peroxide as GRAS – generally recognized as safe – for humans at low doses. Still, H2O2 may cause irritation, burning, and blistering of the skin. If you get it in your eyes, it could cause burning or even an abrasion on the cornea. Breathing in hydrogen peroxide at higher concentrations can irritate airways, shortness of breath, cause tightness in your chest, or hoarseness.

And swallowing it, especially at higher concentrations, can cause vomiting, inflammation, or damage to hollow organs.

Researchers have studied H2O2 for more than 100 years. Some people believe that drinking or injecting a solution with a 35% concentration of food-grade H2O2 cures cancer. This is not the case. In fact, ingesting food-grade hydrogen peroxide can cause severe health problems, including stroke-like symptoms. [1]

And here’s a fun fact: Do you know why hydrogen peroxide comes in a tinted bottle? H2O2 decomposes in the presence of light! Hence, because of its instability, hydrogen peroxide typically is stored with a stabilizer in a weakly acidic solution in a dark-colored bottle. (Thanks, Bill Nye!)

In the mid-1900s, scientists studied the effects of hydrogen peroxide and cancer on animals. There were some favorable findings, but most of the results that hydrogen peroxide had limited effects on cancer.

So, is there a place for hydrogen peroxide in the fight against cancer? The answer is yes – and no. Here’s how today’s science addresses H2O2 …

The ‘Warburg Effect’ and cancer

Otto Warburg won a Nobel Prize in 1931 for discovering that cancer cells produce energy via a process called glycolysis, the first step in the breakdown of glucose to extract energy for cellular metabolism. (Noncancerous cells produce energy via oxidative phosphorylation – and can use glycolysis when there isn’t enough oxygen.) [2]

The “Warburg Effect” is when cancer cells survive without oxygen. This led researchers to ponder if low oxygen levels cause cancer. From there, the hypothesis was born that oxygenating compounds, including hydrogen peroxide, would kill cancer cells. The premise is that by flooding cancer cells with more oxygen than they can handle, the cells will die (necrosis).

However, there has been renewed interest in Warburg’s work and, oddly, his diet. Warburg was obsessed with his diet. While he believed cancer was preventable, he also thought chemicals added to food and used in agriculture cause tumors.

Today, researchers continue to dig into how diet – specifically, sugar-heavy diets – result in elevated levels of insulin and could steer cells to the Warburg effect and, ultimately, cancer.

What is hydrogen peroxide?

Hydrogen peroxide is a pale blue liquid, which appears colorless in a dilute solution, and is slightly thicker than water. H2O2 is a weak acid with strong oxidizing properties; this makes it a powerful bleaching agent, mostly used for paper, and also handy as a disinfectant and as an oxidizer. Hydrogen peroxide in the form of carbamide peroxide is widely used for tooth whitening (bleaching).

Hydrogen peroxide, which has a bitter taste, is a colorless liquid at room temperature. Gaseous H2O2 occurs naturally in the air but decomposes readily to oxygen and water and releases heat. While hydrogen peroxide is not flammable, it is an oxidizing agent that can cause spontaneous combustion with organic material. In high concentration, H2O2 is a component of rocket fuels, used as a bleach for textiles and paper, for producing foam rubber and organic chemicals.

At low temperatures, hydrogen peroxide is a crystalline solid with a strong, irritating odor. (If you’ve ever smelled a pulpwood plant, you know the stench.) In 1998, the Environmental Protection Agency approved H2O2 as a substitute for chlorine in water and sewage treatment.

Hydrogen peroxide and the human body

H2O2 is a component of living cells and plays an important role in host defense and oxidative biosynthetic reactions. There also is evidence that at low levels, H2O2 is a signaling agent, particularly in higher organisms. [3]

H2O2 can modulate both contraction and growth-promoting pathways with more far-reaching effects. The accumulation of hydrogen peroxide in the skin causes vitiligo, a long-term skin condition characterized by patches of the skin losing their pigment. [4]

There is scientific evidence that suggests hydrogen peroxide plays a role in cancer development. Data shows that cancer cells produce high amounts of H2O2, which has been linked to alterations in cancer, including DNA changes, cell proliferation, resistance to apoptosis, metastasis, angiogenesis, and hypoxia-inducible factor 1 (HIF-1) activation. [5]

On the other hand, there is evidence that H2O2 can induce apoptosis in cancer cells. Also, several anticancer drugs are enhanced, at least in part, by hydrogen peroxide.

Hydrogen peroxide and the FDA

The FDA became concerned about the human consumption of hydrogen peroxide in the 1980s. Companies were marketing high-strength versions not only to people with cancer but also to other ailments, including AIDS.

In 1989, the FDA advised the public not to use H2O2 internally and warned that it can cause serious harm or death. In 2006, the FDA again advised hydrogen peroxide “can cause serious harm or death when ingested.”

“No one has presented any evidence that hydrogen peroxide taken internally has any medical value,” said Dr. Steven Galson, a former acting Surgeon General of the United States. “In fact, consuming hydrogen peroxide in the manner touted by these websites could lead to tragic results.”

FDA has never approved high-strength hydrogen peroxide to be taken internally and considers hydrogen peroxide at 35 percent strength dangerous, even if handled according to the manufacturer's directions. High-strength hydrogen peroxide — more than 10 times stronger than the solution used in over-the-counter drugs to disinfect minor cuts — is highly corrosive. [6]

Ingesting hydrogen peroxide can cause gastrointestinal irritation or ulceration. Intravenous (IV) administration of hydrogen peroxide can cause inflammation of the blood vessel at the injection site, gas embolisms (bubbles in blood vessels), and potentially life-threatening allergic reactions.

“When you swallow just a little bit of this food-grade hydrogen peroxide, quite a bit comes out into your stomach and into your intestines and can get absorbed [into the blood stream] and cause bad things,” says Dr. Stephen Hendriksen with Hennepin Healthcare in Minnesota. Ingesting 2 ounces of hydrogen peroxide (about four tablespoons) releases 1.5 gallons of gas into the body.

“When these things go bad, they go bad very suddenly,” adds Dr. Eric Lavonas, a toxicologist with the Rocky Mountain Poison and Drug Center who has treated patients who have ingested hydrogen peroxide. [7]

“I don’t recommend or see the value of taking it at all,” said Lavonas, noting he’s not aware of the chemical having a proven role in the treatment of any disease.

Hydrogen peroxide and cancer

OK, we’re going to put on our science goggles and get into the weeds. Taking a big swig of hydrogen peroxide is not beneficial. In fact, it can do more harm than good if you embrace the bottom-up approach. But that doesn’t mean H2O2 does not have a place in addressing cancer.

Oxygen-derived free radicals, aka reactive oxygen species (ROS), play a part in immunity, cell growth, and cell signaling. However, too much ROS is lethal to cells; and an overabundance of these molecules leads to diseases.

The primary physiological function of NADPH oxidase (NOX) is the production of ROS. These enzymes play roles in the functioning of wound healing, defense, cell differentiation, proliferation, and gene expression. When the NOX enzymes are altered they can be associated with the progression of cancer. [8]

However, NOX enzymes can modulate the proliferation and differentiation of stem cells which makes them a potential tool and target in stem cell therapies, tissue engineering, and regenerative medicine.

Altered versions of NOX enzymes have been seen in different cancers [9]. Because of the effects of ROS increase, invasiveness, and spread of cancer cells, NOX enzymes have been proposed as targets in cancer therapies, including lung, colon, thyroid, and prostate cancer [9-11].

Now, that’s about 200 words without one mention of “hydrogen peroxide.” So, here’s where H2O2 comes into the discussion:

GC4419 (avasopasem manganese) is a highly selective dismutase mimetic. It is being developed by Galera Therapeutics to address radiation-induced severe oral mucositis (SOM). SOM is a complication that head and neck cancer patients endure after radiotherapy. Often, these patients suffer significant pain and the inability to eat solid food or drink liquids. [12]

Radiation therapy increases superoxide radical levels, which are believed to cause most of the side effects, including oral mucositis. Dennis Riley, Ph.D., with Galera Therapeutics says the synthetic enzyme GC4419 “mimics the function of the naturally-occurring superoxide dismutase, an enzyme that converts superoxide to molecular oxygen and hydrogen peroxide.

After a successful Phase 2b clinical trial, the FDA granted Fast Track and Breakthrough Therapy designations to avasopasem manganese for the reduction of SOM. A Phase 3 clinical trial is currently recruiting patients to determine if GC4419 administered prior to intensity-modulated radiation therapy (IMRT) reduces the severity of oral mucositis in patients who have been diagnosed with locally advanced, non-metastatic squamous cell carcinoma of the head and neck.

Summary of Science

Hydrogen peroxide (H2O2) is a mild antiseptic; it is used to prevent infection of minor cuts, scrapes, and burns. It is not recognized as a health supplement by the U.S. Food and Drug Administration.

Still, there is evidence that H2O2 can induce apoptosis (cell death) in cancer cells. In fact, several anticancer drugs are enhanced, at least in part, by hydrogen peroxide.

However, scientific research suggests hydrogen peroxide also can play a role in cancer development. Data shows that cancer cells produce high amounts of H2O2, which has been linked to alterations in cancer, including DNA changes, cell proliferation, resistance to apoptosis, metastasis, angiogenesis, and hypoxia-inducible factor 1 (HIF-1) activation.

Bottom line: For cancer patients, the use of hydrogen peroxide should only come from the direction of a doctor.


  1. Questions for pseudoscience: Hydrogen Peroxide Therapy.
  2. Lactate for carcinogenesis may explain ‘Warburg Effect.’
  3. Hydrogen Peroxide: A Signaling Messenger.
  4. Hydrogen Peroxide Regulates the Cholinergic Signal in a Concentration Dependent Manner.
  5. Dual Role of Hydrogen Peroxide in Cancer: Possible Relevance to Cancer Chemoprevention and Therapy.
  6. High-Strength Hydrogen Peroxide.
  7. How Peddlers of ‘Food-Grade’ Hydrogen Peroxide Exploit the Sick.
  8. Natural Compounds as Modulators of NADPH Oxidases.
  9. NADPH Oxidases NOXs and DUOXs as Putative Targets for Cancer Therapy.
  10. Reactive Oxygen Species in Stem Cells.
  11. Curcumin inhibits the invasion of lung cancer cells by modulating the PKCα/Nox-2/ROS/ATF-2/MMP-9 signaling pathway.
  12. Galera Therapeutics Announces Two-Year Tumor Outcomes Data for GC441.