Hydrogen Peroxide Therapy for Cancer?
Hydrogen peroxide (H2O2) is a chemical compound that is naturally produced in the human body, widely found in nature, and has a range of different applications, and has been included in regimens for alternative cancer therapies.
Hydrogen peroxide is commonly known as a bleaching agent, antiseptic and disinfectant. It has potent oxidizing properties and kills almost all types of harmful pathogens . It is frequently used today as a topical antibacterialA substance that kills bacteria or stops them from growing and causing disease. or bleaching product for skin, hair or other superficial uses including wound cleaning, acne, and even skin cancer  .
It was first discovered in the 1800s and began to be used as a treatment for numerous diseases. The first scientific studies on the medical use of hydrogen peroxide appeared in the literature after World War I with impressive results on survival rates of pneumonia patients .
Charles H. Farr, MD, PhD, also known as the “father of oxidative medicine”, popularized the therapeutic benefits of intravenous (IV) hydrogen peroxide. Hydrogen peroxide is an oxidative therapy, which increases tissue and cell oxygen concentrations to high levels. It also stimulates the immune system to eliminate pathogens and cancerous cells.
Dr. Farr conducted experimental research in patients and observed that IV hydrogen peroxide treatment could rapidly relieve allergic reactions, influenza symptoms, chronic candidiasis, and acute viral and bacterial infections. He also demonstrated that hydrogen peroxide had potent anti-tumor effects . Many alternative practitioners believe that hydrogen peroxide is a wonder molecule and panacea for numerous conditions.
Early researchers wrongly believed that hydrogen peroxide only had toxic effects on cells in the body. Scientific research now shows that hydrogen peroxide is an essential metabolite and important signaling molecule that is involved in many of life’s most important biological processes  . White blood cells naturally produce hydrogen peroxide as the first line of defense against infections and invading organisms such as parasites, viruses, bacteria, fungi, and yeasts .
The ability of cells to produce hydrogen peroxide is essential for life. It is not a toxic byproduct, but rather a requirement for health and survival. Proteins, carbohydrates, fats, vitamin and mineral metabolism, immunity, and other essential functions all require hydrogen peroxide.
The biological importance of hydrogen peroxide and its ability to fight infections is universally accepted. However, when it comes to oral ingestion or injections directly into the bloodstream there is controversy in the medical community. Claims of therapeutic benefits, especially for cancer, are heavily debated with some believing it is ineffective and dangerous .
This article seeks to provide more details about hydrogen peroxide therapy for cancer, how it works, what the science says, what the risks are, and give further insight into the claims of benefits for cancer patients.
Hydrogen peroxide was discovered in 1818 by Louis-Jacques Thénard who called it eau oxygénée (oxygenated water). Since the 1850s hydrogen peroxide has been widely used for a range of different purposes, including bleaching, as an oxidizing agent, disinfectant in food and even fuel for rockets .
The first documented medical use of hydrogen peroxide was described by Love et al as an effective treatment for numerous diseases, including scarlet fever, diphtheria, whooping cough, asthma, hay fever, and tonsillitis  . The first reports in the medical literature on the benefits of hydrogen peroxide therapy came from the doctors Oliver and Cantab. In 1920, they reported to the Lancet that intravenous infusions were used to successfully treat pneumonia patients in the epidemic following World War I. They only treated cases they deemed hopeless as there were still perceived risks around the therapy. They managed to save 50% of the patients they treated who would have almost certainly died otherwise  .
Despite promising early results, medical interest in further research into hydrogen peroxide waned in the 1940s due to the emergence of new prescription drugs and modern medicine . In the 1960s, there was a resurgence of interest and studies found that hydrogen peroxide could be used to promote oxidation. This is when oxidative therapy was pioneered. Oxidative therapy is postulated to stimulate the immune system by using oxygen, ozone gas, or hydrogen peroxide and was used to treat certain cancers, skin diseases, and even polio .
However, Dr. Charles Farr, with the studies he conducted in the 1980s, is generally considered to be the most prominent pioneer and researcher on oxidative therapy and the intravenous infusion of hydrogen peroxide to treat a wide range of conditions  . Later, Fr. Richard Willhelm promoted the therapeutic use of hydrogen peroxide to treat cancer. He defined hydrogen peroxide as ‘God's given immune system’.
There is certainly controversy in the scientific literature about the use of hydrogen peroxide when ingested orally or injected intravenously. Some studies warn that the treatment, as promoted by alternative or integrative medicine practitioners, is potentially dangerous .
However, hydrogen peroxide is approved for topical use in concentrations of 1% to 45% for a range of clinical purposes including wound care, promoting venous insufficiency ulcer healing, acne, actinic keratoses, skin cancers and other novel applications continue to be explored .
Recent studies have shown that cancer cells produce hydrogen peroxide . Some researchers have hypothesized that it may actually act as a fertilizer in the tumor microenvironment that fuels cancer growth. High levels of peroxides cause oxidative stress, which drives accelerated aging, DNA damage, inflammation and cancer metabolism .
However, catalase is the primary enzymeA protein that speeds up chemical reactions in the body. that detoxifies hydrogen peroxide in the body. Therefore, it is theorized that a catalase-deficiency may predispose toward the development of cancer rather than hydrogen peroxide being the culprit itself. It appears that the inability to detoxify hydrogen peroxide due to a catalase deficiency promotes tumor initiation and disease progression .
Research shows that hydrogen plays a vital role in normal cellular function and signaling, but at supraphysiological concentrations (more than normally occurs in the body) causes oxidative damage and cytotoxicity (toxicity to cell) . Hence, hydrogen peroxide can have both positive (signaling) and negative (damage) effects depending on the level of hydrogen peroxide, enzyme activity and the cell type under investigation .
Clinical research shows that hydrogen peroxide has cytotoxic effects on cancer cells and can counteract tumor hypoxia, which is a major constraint in the efficacy of radiotherapy  . These properties are exploitable for the treatment of cancer in combination with radiation therapy. A 2020 clinical trial has shown positive results in 12 patients with locally advanced breast cancer and demonstrated that local injections of hydrogen peroxide directly into tumors are a safe and simple intervention with the potential for high impact and efficacy .
These studies corroborate the early findings of doctors in the 1960s from the Baylor University Medical Center, TX, USA, who studied the effect of hydrogen peroxide combined with radiotherapy as a cancer treatment. The results of their studies included an 88-year-old man with squamous cell carcinoma of the cheek, who, after treatment, was alive and cancer-free 6 years later. The study also included a 29-year-old man with a fungating mass under the tongue and gangrene of the jaw who made a full recovery after treatment . Both cases, under normal circumstances, would not have been expected to survive more than a few months. The researchers modestly reported that their preliminary results “suggest an improvement in the radiotherapeutic ratio” .
In summary, it certainly seems that hydrogen peroxide has a role to play in the treatment of cancer, but more research is still required to confirm if it is a safe and effective treatment in its own right. Evidence suggests that it may have potential therapeutic applications, is safe and effective for topical use or local injections in conjunction with conventional treatments.
Hydrogen peroxide is approved for topical use for certain dermatologic conditions and may help in the treatment of skin cancer . It has been shown to be a safe and effective method to combat tumor hypoxia and improve the efficacy of conventional treatment for superficial tumors . As a primary cancer treatment more research is still needed, but its immune signaling effects and anti-tumor properties may have potential therapeutic applications in cancer care.
Hydrogen peroxide treatment is an oxidative therapy that stimulates oxidation. This is believed to increase cellular energy metabolism, support detoxification, and activate the immune system to fight cancer. According to proponents of hydrogen peroxide therapy the potential benefits include:
- Immune system activation
- Triggers production of white blood cells, interferon, tumor necrosis factor, and other cytokines that combat infections and fight cancer.
- Anti-viral, antibacterial and antifungalA drug that treats infections caused by fungi. properties
- Improves the efficiency of antioxidant enzymes
- Increases blood and tissue oxygen levels
- Anti-angiogenic (stops formation of new blood cells)
- Inhibits growth of anaerobic organisms and kills pathogens
- Kills cancer cells
- Anti-tumor effects
- Inhibits tumor growth
- Helps to prevent metastases and disease progression
- Neutralizes toxinsA poison made by certain bacteria, plants, or animals, including insects. and aids in detoxification
- Improves mitochondrial function
Purported mechanism of action:
For many years after its discovery hydrogen peroxide was viewed as a toxic molecule to human tissues. However, more recent research informs us that it is a ubiquitous endogenous molecule of life that plays a key pro-survival role in diverse physiological processes, including the activation of immune cells to target and breakdown cancer cells  .
Hydrogen peroxide is a reactive oxygen species (ROS) that directly creates oxidative stress as a molecular oxidant and indirectly through free radical generation . It is well established that oxidative stress damages cells and is associated with the onset and progression of many diseases . For this reason, all aerobic (requires oxygen) organisms have antioxidant enzymes that limit oxidative stress (imbalance of ROS) and detoxify excess reactive oxygen species such as hydrogen peroxide . Antioxidant enzymes have been shown to function as peroxide sensors and are emerging as key regulators of the many pathways that respond to hydrogen peroxide .
When a patient undergoes hydrogen peroxide therapy for cancer, it is administered intravenously, which means directly into the vein. Hydrogen peroxide enters the bloodstream and is broken down into water and oxygen by an enzyme called catalase in the plasma and white blood cells. Later, it penetrates the cell membrane of red blood cells and reacts with catalase within the cell releasing yet more oxygen .
The treatment increases the oxygen content of the cells and tissues to levels that parallel or exceed that of hyperbaric oxygen therapy . It is a powerful pro-oxidant that has been shown to wipe out harmful pathogens and kill cancer cells in animal studies . The biological killing activities and anti-cancer effects of hydrogen peroxide may also be linked to the fact that it stimulates natural killer cells and monocytes (immune cells) to produce interferon, tumor necrosis factor, and other cytokines (signaling molecules) involved in regulating cell growth and modulating the immune response to fight cancer .
Furthermore, it is well known that cancer thrives in a low oxygen environment. The phenomenon is called tumor hypoxia. The microenvironment of a tumor is generally characterized by low pH values, high glutathione levels, an overproduction of hydrogen peroxide and severe hypoxia. These hallmark characteristics lead to increased angiogenesis (formation of new blood vessels), tumor progression, metastases (cancer spread) and treatment resistance .
Hydrogen peroxide, once broken down by catalase, supersaturates the bloodstream and tissues with oxygen, which is believed to inhibit the growth of anaerobic organisms and cancer cells. This is known as hyperoxia, which has potential anti-tumor effects and may help to prevent disease progression . It also oxidizes toxins and biological waste products, which increases the rate of metabolism in the mitochondria (powerhouses of the cell). This increases available energy for cellular repair and regeneration .
Tumor hypoxia is also a major constraint in the use of radiotherapy and certain types of chemotherapy. Hydrogen peroxide is therefore also used in conjunction with conventional treatment to enhance efficacy, especially radiotherapy .
Risks and Side Effects
If you are considering hydrogen peroxide as an alternative therapy for cancer caution is advised. There are risks involved with hydrogen peroxide treatment and self-administration is not recommended.
In clinical settings, provided treatment guidelines are adhered to, hydrogen peroxide therapy has been shown to be relatively safe in terms of topical application, intratumoral injections and intravenous use in dilute concentrations. However, it is not advised to take hydrogen peroxide orally as this can cause serious side-effects, especially in higher concentrations, and damage the stomach  .
Injecting high concentrations of hydrogen peroxide can cause:
- Inflammation of the blood vessels at the injection site
- Oxygen bubbles that block flood flow and lead to gas embolisms, which can be fatal
- Destruction of red blood cells (red cell hemolysis)
- Kidney failure
Oral ingestion of high concentrations of hydrogen peroxide can cause:
- Mouth, throat, and stomach burns
- Foaming at the mouth
- Stomach bloating
- Loss of consciousness
- Trouble breathing
Inhaling the vapors of 35 percent hydrogen peroxide can cause breathing problems. You can also develop blisters and burns if your skin comes into contact with it .
Is hydrogen peroxide a beneficial treatment for cancer?
Hydrogen peroxide may have a role to play in treatment of cancer. However, scientific research is still lacking on hydrogen peroxide as a primary cancer treatment. There is evidence to show it may be beneficial to improve the efficacy of conventional treatments such as radiotherapy. If you are considering the treatment you should discuss it with your oncologist.
Is it safe? What are the risks?
Hydrogen peroxide can be administered safely and effectively to aid in the treatment of cancer. However, if misused, hydrogen peroxide can be toxic and cause serious side-effects or even death.
How is hydrogen peroxide administered as a cancer therapy?
Hydrogen peroxide is most commonly used topically to aid in the treatment of certain skin conditions and skin cancers. It can also be given as an injection directly into tumors to increase oxygen levels, counteract tumor hypoxia, and improve the efficacy of conventional therapies. Intravenous hydrogen peroxide may also be recommended by integrative medicine practitioners as an oxidative therapy to activate the immune system and help to combat cancer.
 Douglass, William Campbell MD. Hydrogen Peroxide – Medical Miracle (H202). Rhino Publishing. Panama. 1990.
 Murphy EC, Friedman AJ. Hydrogen peroxide and cutaneous biology: Translational applications, benefits, and risks. J Am Acad Dermatol. 2019 Dec;81(6):1379-1386. https://pubmed.ncbi.nlm.nih.gov/31103570/
 Farr, C. H. MD, PhD. The Therapeutic use of Intravenous Hydrogen Peroxide. A Review. Experimental Evidence of Physiological Effect and Clinical Experience. 1986.
 Veal, Elizabeth A. et al. Hydrogen Peroxide Sensing and Signaling. Molecular Cell, Volume 26, Issue 1, 1 – 14. https://doi.org/10.1016/j.molcel.2007.03.016
 Atwood, Kimball. (2007). Charles H. Farr and the purported scientific and medical rationale for intravenous hydrogen peroxide. Scientific Review of Alternative Medicine. 11. 11-18. https://www.researchgate.net/publication/288204519_Charles_H_Farr_and_the_purported_scientific_and_medical_rationale_for_intravenous_hydrogen_peroxide
 Armogida, M., Nisticò, R. and Mercuri, N.B. (2012), Therapeutic potential of targeting hydrogen peroxide metabolism in the treatment of brain ischaemia. British Journal of Pharmacology, 166: 1211-1224. https://doi.org/10.1111/j.1476-5381.2012.01912.x
 Nathan CF, Cohn ZA. Antitumor effects of hydrogen peroxide in vivoThis means "in the body.". J Exp Med. 1981 Nov 1;154(5):1539-53. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2186528/
 Murphy EC, Friedman AJ. Hydrogen peroxide and cutaneous biology: Translational applications, benefits, and risks. J Am Acad Dermatol. 2019 Dec;81(6):1379-1386. https://pubmed.ncbi.nlm.nih.gov/31103570/
 Yang G, Ji J, Liu Z. Multifunctional MnO2 nanoparticles for tumor microenvironment modulation and cancer therapy. Wiley Interdiscip Rev Nanomed Nanobiotechnol. 2021 Nov;13(6):e1720. https://pubmed.ncbi.nlm.nih.gov/33908171/
 Laurinda Mordh, RN, BSN. Hydrogen Peroxide. An Oasis of Healing. https://www.anoasisofhealing.com/hydrogen-peroxide/
 Hu, R., Saito, A. I., Mitsuhashi, T., Inoue, T., Ota, T., Ujihira, T., Yoshida, K., Sasai, K.”Radiosensitization using hydrogen peroxide in patients with cervical cancer”. Molecular and Clinical Oncology 15.1 (2021): 142. https://doi.org/10.3892/mco.2021.2304
 Lisanti MP, Martinez-Outschoorn UE, Lin Z, Pavlides S, Whitaker-Menezes D, Pestell RG, Howell A, Sotgia F. Hydrogen peroxide fuels aging, inflammation, cancer metabolism and metastasis: the seed and soil also needs “fertilizer”. Cell Cycle. 2011 Aug 1;10(15):2440-9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3180186/
 Nimalasena et al (2020). Intratumoural hydrogen peroxide with radiotherapy in locally advanced breast cancer: results from a Phase I clinical trial. International Journal of Radiation Oncology*Biology*Physics. 108. 4. 2020. https://www.sciencedirect.com/science/article/pii/S0360301620313092
 Love, I. N. “PEROXIDE OF HYDROGEN AS A REMEDIAL AGENT.: Read before the St. Louis Medical Society, February 4, 1888.” Journal of the American Medical Association 10.9 (1888): 262-265. https://media.ellinikahoaxes.gr/uploads/2020/08/love1888.pdf
 Bottaro, Angelica. What Is Hydrogen Peroxide Therapy? Exploring the grey area of oxidative therapy for cancer. Very Well Health. Sept 2021. https://www.verywellhealth.com/hydrogen-peroxide-therapy-5198732
 Cafasso, Jacquelyn. Can Hydrogen Peroxide Cure Cancer? Healthline. August 2020. https://www.healthline.com/health/hydrogen-peroxide-cancer
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 supplementA product, generally taken orally, that contains one or more ingredients (such as vitamins or amino acids) that are intended to supplement one's diet and are not considered food. 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. 
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 glucoseA type of sugar; the chief source of energy for living organisms. to extract energy for cellular metabolism. (Noncancerous cells produce energy via oxidative phosphorylationThe metabolic pathway cells use enzymes to oxidize nutrients, releasing the chemical energy of molecular oxygen, which is used to produce adenosine triphosphate (ATP). – and can use glycolysis when there isn’t enough oxygen.) 
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. 
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. 
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 apoptosisA type of cell death in which a series of molecular steps in a cell lead to its death. This is one method the body uses to get rid of unneeded or abnormal cells. The process of apoptosis may be blocked in cancer cells. Also called programmed cell death., metastasisThe spread of cancer cells from the place where they first formed to another part of the body. In metastasis, cancer cells break away from the original (primary) tumor, travel through the blood or lymph system, and form a new tumor in other organs or tissues of the body. The new, metastatic tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the lung, the cancer cells in the lung are breast cancer cells, not lung cancer cells., angiogenesis, and hypoxia-inducible factor 1 (HIF-1) activation. 
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 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. 
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. 
“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 bottoms-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 many ROS are lethal to cells; and 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. 
However, NOX enzymes can modulate proliferation and differentiation of stem cells which make 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 . 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. 
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.
Hydrogen peroxide 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. H2O2 in the form of carbamide peroxide is widely used for tooth whitening (bleaching).
The U.S. Food and Drug Administration classifies hydrogen peroxide as “generally recognized as safe” – GRAS – for humans at low doses. Still, H2O2 may cause irritation, burning, and blistering of the skin. It is not recognized as a health supplement.
There is evidence that hydrogen peroxide plays a role in cancer development, including DNA changes, cell proliferation, resistance to apoptosis, metastasis, angiogenesis, and HIF-1 activation. However, there is also evidence that H2O2 can induce apoptosis in cancer cells. (Several anticancer drugs are enhanced, at least in part, by hydrogen peroxide.)
No. In fact, ingesting food-grade hydrogen peroxide can cause severe health problems, including stroke-like symptoms.
Yes. A Phase 3 clinical trial seeks to determine if GC4419 (a synthetic enzyme) 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.
- Questions for pseudoscience: Hydrogen Peroxide Therapy. https://www.youtube.com/watch?v=FOBwg3_m_2k
- Lactate for carcinogenesis may explain ‘Warburg Effect.’ https://www.cancertutor.com/lactate-warburg-effect/
- Hydrogen Peroxide: A Signaling Messenger. https://pubmed.ncbi.nlm.nih.gov/16677071/
- Hydrogen Peroxide Regulates the Cholinergic Signal in a Concentration Dependent Manner. https://pubmed.ncbi.nlm.nih.gov/17335854/
- Dual Role of Hydrogen Peroxide in Cancer: Possible Relevance to Cancer Chemoprevention and Therapy. https://pubmed.ncbi.nlm.nih.gov/17150302/
- High-Strength Hydrogen Peroxide. https://wayback.archive-it.org/7993/20170112170534/http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm150592.htm
- How Peddlers of ‘Food-Grade’ Hydrogen Peroxide Exploit the Sick. https://undark.org/2018/08/20/food-grade-hydrogen-peroxide-cancer/
- Natural Compounds as Modulators of NADPH Oxidases. https://www.hindawi.com/journals/omcl/2013/271602/
- NADPH Oxidases NOXs and DUOXs as Putative Targets for Cancer Therapy. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6365101/
- Reactive Oxygen Species in Stem Cells. https://www.hindawi.com/journals/omcl/2015/159080/
- Curcumin inhibits the invasion of lung cancer cells by modulating the PKCα/Nox-2/ROS/ATF-2/MMP-9 signaling pathway. https://doi.org/10.3892/or.2015.4044
- Galera Therapeutics Announces Two-Year Tumor Outcomes Data for GC441. https://www.galeratx.com/galera-therapeutics-announces-two-year-tumor-outcomes-data-for-gc4419