There a lot of differing views reports on pH levels and cancer. Some say that cancer only grows in acidic bodies. Some say that an alkaline body can prevent or cure cancer.

Many others disagree calling it a "myth".

What this question is:

Is there a link between pH levels and cancer?

What this question isn't:

This question isn't about alkaline diets, ash diets or any other diets or whether they work or not.


I'm aware that the body is naturally slightly alkaline. I mean average pH.

  • Does this (at least partially) answer your question? skeptics.stackexchange.com/questions/13604/…
    – nico
    Apr 1 '14 at 6:18
  • @nico: There are different claims. Acid causes (all) cancer versus fungus causes (all) cancer.
    – Oddthinking
    Apr 1 '14 at 8:12
  • 1
    @Oddthinking: I know they are different claims, I am not saying this is a duplicate. Still, bicarbonate is an antiacid, so the other question (although it does not answer this one) can give some interesting references on the importance of pH for cancer treatment.
    – nico
    Apr 1 '14 at 9:26
  • There are so many variables in whether or not you'll contract cancer (although genetics seem to be a strong indicator) that it's basically impossible to say that X causes cancer without hard evidence that it was the only variable involved. We know things like cigarettes, ionising radiation and certain mutagenic chemicals can cause cancer from medical experiments. Unless there's a rigorous medical experiment that proves body PH is a factor then any claims that it is are dubious.
    – GordonM
    Jul 18 '17 at 16:24
  • the PH of the body isn't even uniform and it's very carefully regulated by numerous systems. Trying to mess up your body's PH can kill you and won't cure your cancer.
    – magisch
    Jul 19 '17 at 13:59


cancer only grows in acidic bodies ... an alkaline body can prevent or cure cancer.

This is certainly over-simplistic, probably meaningless, almost certainly useless.

Average body pH

I suspect this is not a meaningful thing to attempt to measure. In terms of cancer, it may be no more meaningful than average body thickness, average body density or average body conductivity.

Our bodies are made up of many materials with varying pH:

Stomach:                2.0  ±1
Stomach with food:      4.5  ±0.5
Adipose:                7.0  ±0.1
Blood:                  7.40 ±0.05
Small Intestine:        8    approx
Muscle tissue spaces:   alkaline
Muscle fibre interior:  acid    
Urine:                  4.6 - 8       

Should we make an average by volume?, by mass? Should it be a weighted average? Should we measure and monitor the pH of hundreds or thousands of different tissues, fluids and other materials in our bodies?

Cancer and pH

Cancer is essentially uncontrolled excessive cell division and growth. Therefore we might reasonably interpret the question in terms of intracellular fluid pH and ignore the pH of other materials/fluids in the body.

Cellular pH is regulated. The body has mechanisms that maintain the pH of cells independently of other internal and external factors.

However Cellular pH does play a role in tumor cell survival [4]

pH Control

Can we deliberately alter our cellular pH?

In general, no. We cannot easily or safely manipulate our cellular pH outside normal ranges. Our cells have mechanisms to regulate pH. If pH goes outside the normal ranges we become ill and may die. [5]



Intracellular pH is difficult to measure and may vary in different types of cells and in different parts of cells.

pH of the plasma (i.e. pH of the plasma of whole blood = conventional "blood" pH) is controlled at 7.4 (7.35 - 7.45).

From D.Brooks, University of Nebraska-Lincoln


The normal human stomach has a pH which can range from approximately 1-3 but is usually closer to 2. When there is food in the stomach the pH can raise to as high as 4-5. After the food leaves the stomach bicarbonate ions are secreted to neutralize and alkalinize the mixture. The pH of the small intestine is approximately 8.

From University of California Santa Barbera


It is only the interior spaces that are alkaline, whereas the interior of the muscle fibres is actually acid.

From University of Rochester


One of the major obstacles to the successful treatment of cancer is the complex biology of solid tumour development. Although regulation of intracellular pH has been shown to be critically important for many cellular functions, pH regulation has not been fully investigated in the field of cancer. It has, however, been shown that cellular pH is crucial for biological functions such as cell proliferation, invasion and metastasis, drug resistance and apoptosis. Hypoxic conditions are often observed during the development of solid tumours and lead to intracellular and extracellular acidosis. Cellular acidosis has been shown to be a trigger in the early phase of apoptosis and leads to activation of endonucleases inducing DNA fragmentation. To avoid intracellular acidification under such conditions, pH regulators are thought to be up-regulated in tumour cells. Four major types of pH regulator have been identified: the proton pump, the sodium-proton exchanger family (NHE), the bicarbonate transporter family (BCT) and the monocarboxylate transporter family (MCT). Here, we describe the structure and function of pH regulators expressed in tumour tissue. Understanding pH regulation in tumour cells may provide new ways of inducing tumour-specific apoptosis, thus aiding cancer chemotherapy.

From Cellular pH regulators: potentially promising molecular targets for cancer chemotherapy.


Cells must constantly maintain their pH in order to function properly. In animals, for example, the maintainence of blood pH is crucial for life. A slightly acidic pH (6.95) would result in coma and death. A slightly more basic pH (7.7) would result in convulsions and muscle spasms.


  • 1
    I think it would be important to note that the origin of these claims is most probably the fact that the environment around a tumour (and not in the whole body) is more acidic, in part due to the high metabolic rate of tumour cells. This however has no causal relation to tumour development, and it is rather a consequence of it.
    – nico
    Apr 4 '14 at 6:50
  • @nico I don't think that's true. The local acidosis around tumors promotes their growth.
    – HappySpoon
    Jun 30 '14 at 9:12
  • @HappySpoon: I am not sure I follow your reasoning... could you expand?
    – nico
    Jun 30 '14 at 10:12

Question: Is there a link between pH levels and cancer?

Yes, there is.

In this review of tumor progression and metastatic dissemination, it is stated:

Hypoxia, elevated interstitial fluid pressure, low glucose and high lactate concentration resulting from a predominant anaerobic metabolism, are responsible of low extracellular pH (pHe) in tumor tissues. As a consequence, the second metabolic hallmark of tumor environment is tumor acidosis. [1]

As a result:

  • Tumor acidity tends to correlate with cancer aggressiveness; in part, this reflects the ability of HIF-1 to promote invasiveness and angiogenesis.

  • extracellular acidity per se boosts the invasiveness and metastatic capacity of cancer cells

  • this acidity renders cancer cells relatively resistant to the high proportion of chemotherapeutic drugs that are mildly basic, and may impede immune rejection of tumors

Thus, practical strategies for raising the extracellular pH of tumors may have therapeutic utility. [2]

So a number of things are being tried experiementally including

  • oral bicarbonate in rodents inhibits metastatic activity and response to chemotherapeutic agents

  • Computer simulation used to verify the ability of sodium bicarbonate to increase pHe of tumors in vivo also indicates that the normalization of tumor acidity reduces invasiveness of tumor cells without altering the pH of blood or normal tissues

  • Well-tolerated doses of the proton pump inhibitor esomeprazole have markedly impeded tumor growth and prolonged survival in nude mice implanted with a human melanoma (inhibiting the proton pump on tumor cells leads to a lowering of intracellular pH and rise in extra-cellular pH )

  • pH regulators in tumor cells include extracellular forms of carbonic anhydrase (CA), Na+/HCO3- co-transporters, Na+/H+ exchangers (NHEs), monocarboxylate transporters (MCTs) and the vacuolar H+-ATPase (V-ATPases). The raise of pHe promoted by these inhibitors is constantly associated with a decrease of intracellular pH. Acidity of pHi tends to suppress the efficiency of glycolysis, sustaining the raise of pHe , and may exert anti-proliferative and pro-apoptotic effects on tumor cells themselves. Consequently, pH regulators might be considered true anticancer drugs.

So, modifying the extra-cellular pH around tumors, and also tumor cells intracellular pH are lines of active enquiry in treating cancer at this time.


[1] Calorini L, Peppicelli S, Bianchini F. Extracellular acidity as favouring factor of tumor progression and metastatic dissemination. Exp. Oncol. 2012 Jul;34(2):79-84. PubMed PMID: 23013757. Full text

[2] McCarty MF, Whitaker J. Manipulating tumor acidification as a cancer treatment strategy. Altern Med Rev. 2010 Sep;15(3):264-72. PubMed PMID: 21155627.

  • 6
    I'd like to see a little more context about how advanced these experiments are. This site is likely to be seen by patients and their families, and we shouldn't be seen as promoting unproven treatments.
    – Oddthinking
    Jun 30 '14 at 10:04
  • 2
    At a quick skin through it looks like your answer is saying that cancer can cause acidity in body tissues, so the acidity is an effect rather than a cause?
    – GordonM
    Jul 18 '17 at 16:26

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