# Cancer metabolism

Category: Metabolism

"Cancer metabolism" or stress metabolism typically involves an excess of the adaptive hormones, resulting from an imbalance of the demands made on the organism and the resources available to the organism. Excessive stimulation depletes glucose and produces lactic acid, and…

9 passages · 2 authors · 2014–2025 · Most-cited: [Ray Peat](https://bioenergeticoracle.com/md/voices/ray-peat/index.md)

Canonical page: https://bioenergeticoracle.com/concepts/cancer-metabolism

## Synthesis

**Cancer metabolism** is a state of *impaired respiration* in which cells regress to a primitive form of energy production, aerobic glycolysis, even in the presence of oxygen. [Source 2, 7] Otto Warburg discovered this in 1923, observing that cancer cells produce large amounts of lactic acid rather than oxidizing glucose fully to carbon dioxide, a failure of the **Pasteur effect** where respiration normally suppresses fermentation. [Source 2] Peat argued that this is not a genetic defect but a basic adaptive survival process, a metabolic condition triggered when anything—carcinogens, radiation, or prolonged oxygen deprivation—interferes with oxidative metabolism. [Source 5, 7] The cell, facing an energy crisis, dedifferentiates and reverts to glycolysis, a less efficient pathway that extracts far less energy from fuel and produces lactic acid as a waste product. [Source 7]

The shift to cancer metabolism is driven by a systemic energetic failure characterized by excessive stimulation and substrate depletion. When cells are dangerously overstimulated, **oxygen** and **glucose** become depleted, forcing the conversion of glucose to lactate; when glucose is exhausted, glutamine is converted to lactate. [Source 4] This creates a *reductive stress* state, an electron-rich, pseudohypoxic condition that blocks the enzyme pyruvate dehydrogenase and further inhibits glucose oxidation. [Source 4] Peat described how increased **cortisol** activates the Randle effect, shifting the organism toward the oxidation of fat and protein rather than glucose, while also activating fatty acid synthase to produce fatty acids from amino acids and pyruvate in a "futile cycle" that liberates ammonia, which further suppresses respiration and stimulates glycolysis. [Source 1] The flooding of the body with free fatty acids, particularly **polyunsaturated fatty acids**, amplifies inflammatory-carcinogenic processes and produces resistance to thyroid, insulin, and cortisol. [Source 4, 6]

At the cellular level, the metabolic derangement involves a fundamental disruption of electron flow. Szent-Györgyi conceptualized the difference between the primitive and differentiated states as a matter of electron acceptors: in cancer, **pyruvic acid** acts as the electron acceptor, forming lactic acid, whereas in healthy oxidative metabolism, **oxygen** serves as the far more powerful terminal electron acceptor, enabling a higher-voltage energy flow. [Source 7] Dinkov has extended this framing, explaining that excessive fatty acid oxidation blocks electron transport chain complex II via depletion of **flavin adenine dinucleotide (FAD)**, causing a buildup of electrons that the cell resolves by jettisoning its energetically expensive oxidative machinery and reverting to glycolysis. [Source 9] The cancer cell then compensates for its inefficient energy production by massively upregulating glucose transporters, not because it is "addicted" to sugar, but because it perceives a lack of glucose due to its failure to oxidize it properly. [Source 9]

This metabolic state is self-reinforcing and systemic. Lactic acid itself is an irritant that increases the expression of **hypoxia-inducible factor (HIF)**, which in turn causes cells to depend even more on converting glucose to lactic acid. [Source 6] The cancer cell attempts to drain away the excess electrons generated by this reductive imbalance by synthesizing fat, then oxidizing that fat with whatever oxygen is available—a process that is less efficient regarding oxygen use and deepens the oxygen deficiency. [Source 8] Peat emphasized that sugar deprivation, such as ketosis, actually turns on the Warburg effect and the stress reaction, worsening the condition. [Source 8] He identified **progesterone** as a substance that affects all features of cancer metabolism in the right way, while noting that promoters like histamine, serotonin, and muscarinic cholinergic signals have safe antagonists that are underutilized. [Source 3] Aging itself involves a metabolic shift in the direction of cancer metabolism, with increased fat oxidation, decreased glucose oxidation, and a progressive inability to fully restore the high-energy resting state of cells. [Source 4]

## People also ask

### How does impaired respiration lead to cancer metabolism?

Peat argued that when anything interferes with oxidative metabolism, cells face an energy crisis and dedifferentiate, reverting to aerobic glycolysis—a primitive, less efficient energy pathway that produces lactic acid instead of fully oxidizing glucose.

### Why do cancer cells consume so much glucose if they don't use it efficiently?

The corpus explains that cancer cells perceive a lack of glucose because they fail to oxidize it properly, so they massively upregulate glucose transporters to compensate for inefficient energy production, not because they are addicted to sugar.

### What role do fatty acids play in shifting metabolism toward cancer?

Peat described how excessive free fatty acids, especially polyunsaturated fats, amplify inflammatory processes and produce resistance to thyroid, insulin, and cortisol, while excessive fatty acid oxidation can block the electron transport chain and force a reversion to glycolysis.

## Related concepts

- [Cancer](https://bioenergeticoracle.com/md/concepts/cancer/index.md)
- [Antioxidants](https://bioenergeticoracle.com/md/concepts/antioxidants/index.md)
- [Free radicals](https://bioenergeticoracle.com/md/concepts/free-radicals/index.md)
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## Cited passages

Passage numbers match the `[Source N]` markers in the synthesis above.

### Source 1 — Glossary

Ray Peat · Glossary

> Cancer metabolism
>
> "Cancer metabolism" or stress metabolism typically involves an excess of the adaptive hormones, resulting from an imbalance of the demands made on the organism and the resources available to the organism. Excessive stimulation depletes glucose and produces lactic acid, and causes cortisol to increase, causing a shift to the consumption of fat and protein rather than glucose. Increased cortisol activates the Randle effect (the inhibition of glucose oxidation by free fatty acids),
> accelerates the breakdown of protein into amino acids, and activates the enzyme fatty acid synthase, which produces fatty acids from amino acids and pyruvate, to be oxidized in a "futile cycle," producing heat, and increasing the liberation of ammonia from the amino acids. Ammonia suppresses respiratory, and stimulates glycolytic, activity.

### Source 2 — 100 Years of Cancer Metabolism

Ray Peat · Newsletter · 2016

> # 100 Years of Cancer Metabolism
>
> "The cure of human cancer will be the resultant of biochemistry of cancer and of biochemistry of man." — Otto Warburg
>
> Since around 1950, the culture of biology and medicine in the U.S. has been re-engineered in ways that make it incompatible with older ideas on the same subjects, the way new computers are designed so that they can't use old programs. Many people are now writing about "cancer metabolism," especially Otto Warburg's 1923 discovery of cancer's "aerobic glycolysis," but most of them are taking his ideas out of context, to make them fit into the idea that the prime cause of cancer is a genetic defect, whose metabolic consequences might make it possible to kill the mutated cells without harming the rest of the organism. When Warburg observed the production of large amounts of lactic acid by cancer cells in the presence of oxygen, and described it as "impaired respiration," with an absence of the "Pasteur effect," he was placing the cancer problem exactly at the center of the question of the nature of life. One of the implications of his idea was that cancer was a basic adaptive survival process of cells, exactly the sort of thing that would suggest that a "precisely targeted poison" would fail. In Greece more than 2000 years ago, there was already a general understanding of metabolism, in which breathing was seen to be required for maintaining consciousness, vital heat production, assimilation of foods, and organization of functions. The details of oxidative metabolism were mostly unknown until the second quarter of the 20th century, and are still being worked out. In Louis Pasteur's time, the leading chemists believed that fermentation, the production of alcohol from sugar, was produced by lifeless catalysts, activated by oxygen. Pasteur, without knowing any of the details of cell physiology, was able to show that fermentation was an internal process of living organisms, and that they did this in the absence of oxygen. In the presence of oxygen and sugar, the yeast grew without producing alcohol—respiration inhibits fermentation. (The Pasteur Effect that Warburg referred to is the suppression of lactic acid production from glucose in the presence of oxygen.)
>
> Pasteur's work was good physiological chemistry, but the mechanists called it "vitalism," and thought it was unscientific.

### Source 3 — 100 Years of Cancer Metabolism

Ray Peat · Newsletter · 2016

> Lidocaine can be used systemically in small doses, even by transdermal absorption. Opioids stimulate cancer growth and metastasis, but they are still often used (Byrne, et al., 2016). In severe prolonged stress, the body's stress-limiting parasympathetic nervous system can become counter-productive, promoting excitotoxicity, inflammation, and tumor growth. Although it's known that the growth and invasiveness of several types of cancer are stimulated by muscarinic cholinergic signals (including organophosphate insecticides), there seems to be little interest in using belladonna or atropine for treatment. Anticholinergic drugs can alleviate some of the symptoms of cancer, as well as contributing to a restoration of normal metabolism. Histamine and serotonin are other metabolic cancer promoters for which there are safe antagonists. Progesterone affects all of the features of cancer metabolism in the right way. The belief that the only way to eliminate cancer is to kill "every malignant cell" including the "cancer stem cells" was based on the belief that cancer is the result of genetic changes. Even as people are moving away from absolute genetic determinism and are recognizing that there is such a thing as cancer metabolism, they are still focusing on the need to kill the cancer cells, using a combination of surgery, radiation, and chemotherapy.
>
> Recently, an article in the New York Times Sunday Magazine (Sam Apple, "Starving the Beast," May 15, 2016) about the new interest in killing cancer metabolically, quoted James Watson, of DNA fame, as saying "I never thought, until about two months ago, I'd ever have to learn the Krebs cycle. Now I realize I have to." A thorough understanding of the Krebs cycle could lead to an interest in the Pasteur effect, and a reconsideration of the nature of cancer.
>
> [references]

### Source 4 — 100 Years of Cancer Metabolism

Ray Peat · Newsletter · 2016

> These signals include hormones, nutrients, nerve activity, and even nucleic acids circulating in microvesicles or exosomes. During aging, the proportion of unsaturated fat in the body increases, and during stress and inflammation when free fatty acids are released into the blood stream they interfere with oxidative metabolism, while amplifying the inflammatory-carcinogenic processes, providing arachidonic acid, which activates nitric oxide synthesis (Priante, et al., 2005) and is the precursor for prostaglandin synthesis and activator of excitatory processes including protein kinase C (PKC), which is another redox-sensitive regulatory protein (Chu, et al., 2004). Weight loss is often the first symptom that a person notices before a cancer is diagnosed. In cancer, as in sepsis, trauma, and aging, there is a shift toward the oxidation of fat rather than glucose. The flooding of the body with free fatty acids shifts the whole body more strongly toward the pseudohypoxic state of reductive stress, and produces resistance to thyroid, insulin, and cortisol. In starvation, hypoglycemia leads to increased growth hormone secretion (Goldstein, et al., 2011) and an adaptively decreased rate of metabolism, but in the metabolism of a cancer patient, the growth hormone-induced shift to fat oxidation and hypoglycemia fails to decrease energy expenditure. Inflammatory signals contribute to the growth hormone increase, interfering with insulin and the efficient use of glucose. Cellular starvation, beginning with the tumor focus of metabolic inefficiency, increases inflammation, shifting the fuel metabolism, creating pseudohypoxia, in a vicious progression. The cell-quieting effect of sugar oxidation probably involves the greater production of carbon dioxide with a shift of the electronic balance toward a more oxidized and coherent state. Aging itself involves a metabolic shift in the direction of cancer metabolism, with a relative inability to reduce energy expenditure in the basal, fasting state, and with increased fat oxidation, decreased glucose oxidation (Al-Jaouni, et al., 2002). The nature of sleep changes with aging, with a decrease of the restorative deep "slow wave" sleep in old age; this is probably an example of the progressive inability to fully restore the high energy resting state of cells.
>
> With stress and aging, the body's equilibrium on average is less oxidized, and this affects the so-called antioxidants in food.

### Source 5 — Ask the Herb Doctor: Skin Cancer Part 2

Ray Peat · Interview · Dec 21, 2018

> **Ray Peat:** In the 1950s and early 1960s, I was studying literature and painting mostly. Then, from 1968 to 1972, I did a graduate program for a PhD in biology. My approach to research is probably influenced by my literature background—thinking of propaganda analysis and sensitivity to how people use language to manipulate preconceptions. I think everyone looking at the internet has to spend more time thinking about propaganda analysis and how advertising has invaded and practically taken over many of the medical journals.
>
> **Andrew Murray:** Just very quickly, tell people what your specialty was when you graduated and what you looked at in your research.
>
> **Ray Peat:** My dissertation was on the biochemical changes involved in reproductive aging, working on the hamster uterus mostly. I saw how many factors parallel aging in the biochemical pattern that they create. Estrogen excess, progesterone deficiency, vitamin E deficiency, and exposure to radiation all create the same typical age pattern of metabolism. It is at its most extreme in cancer metabolism. That was why I was so interested in Otto Warburg's work at the time I was starting graduate school. American biochemists were turning against Otto Warburg, despite his Nobel Prize, because he was saying that cancer is a metabolic condition, not a gene mutation. Now, 50 years later, the US and European cultures are finally coming around to looking at what Warburg did almost 100 years ago.

### Source 6 — Cancer: Disorder and Energy

Ray Peat · Article · 2014 · https://raypeat.com/articles/articles/cancer-disorder-energy.shtml

> Lactic acid increases the expression of HIF, while HIF causes cells to shift metabolically to depend on converting glucose to lactic acid, that is, to adopt the "cancer metabolism." HIF is recognized as a fundamental problem in "cancer therapy," since HIF allows the cancer to resist the treatment, but the treatment increases HIF.
>
> Radiation, chemotherapy, and surgery all activate these processes of cell replacement, and unless something has changed to improve the organism's recuperative ability, it isn't clear why the cells which replace the missing part should be more able to satisfactorily complete the recovery process than the original cells were. Even the amount of radiation in a single dental x-ray is enough to activate the excitatory-inflammatory processes, and a "therapeutic" x-ray to any part of the body excites similar, but much greater, processes throughout the body. But the ideology of "the cancer cell," and the Gompertz Growth Law, guide the practice of cancer treatment.
>
> Many years ago, Harry Rubin was impressed by hearing from a pathologist that he had been able to find diagnosable cancer somewhere in the body of every person over the age of 50 that he had autopsied. If everyone has cancer by the age of 50, that means that cancer is harmless for most people, and that small cancers might frequently appear, and be spontaneously removed as part of the body's regular house-cleaning. One of the reasons that spontaneous regression of tumors seems so rare is undoubtedly that most tumors are quickly cut out by surgeons.
>
> Preventing injury should be a basic consideration, but the medical slogan, "first do no harm," just doesn't apply to the cancer treatment industry, and this results from the doctrine of "the cancer cell," which is something to be destroyed or kept from multiplying. In the process of diagnosing a cancer, and during the course of treating it, the patient is usually subjected to multiple x-ray examinations, sometimes given radioactive drugs that supposedly concentrate in hidden tumors to emit positrons, and often has toxic contrast agents injected even for MRI examinations. These procedures, even before the destructive "therapies" begin, are adding to the body's inflammatory burden, interfering with the body's ability to complete a healing process. Decisions about pain control usually disregard the effects of the drugs on tumor growth and general vitality—for example, the opiates stimulate histamine release, which increases inflammation and tumor growth.

### Source 7 — Lactate, metabolic regression, & political-medical implications

Ray Peat · Newsletter · 2020

> The futile “War on Cancer” looked for the cause of cancer in viruses and mutant genes, and denied that metabolism could be relevant. The Human Genome Project and the application of genetic engineering to virology, immunology, and other branches of medicine involved a similar belief in the irrelevance of metabolism.
>
> Otto Warburg and Albert Szent-Györgyi shared a general view of life, in which simple life forms could be sustained by glycolysis (forming lactic acid), while oxidative metabolism, with its capacity to extract many times more energy from a given amount of fuel, is necessary to produce and maintain more complex forms of life. Both of them understood cancer to involve a regression to a primitive form of energy metabolism, glycolysis, which produces lactic acid rather than carbon dioxide. (When glycolysis occurs despite the presence of oxygen, it’s called aerobic glycolysis.)
>
> Warburg showed that in cancer, cellular respiration fails to suppress the production of lactic acid, as it does in normal cells, and that cancer can develop as a result of prolonged oxygen deprivation (with the associated lactic acid production). He observed that anything (including carcinogenic chemicals and radiation) that interferes with oxidative metabolism can lead to a series of changes: inflammation, followed by fibrosis, followed by atrophy and death, or sometimes instead of cell death, some of the cells become cancerous, losing their fixed identity as a differentiated element of a specific kind of tissue, and regress, dedifferentiate, to a primitive lactate-producing metabolism with a tendency to migrate to new locations.
>
> Szent-Györgyi, ten years younger than Warburg, recognized the importance of his work, and began a long project of attempting to understand what it is about oxidative metabolism that not only suppresses the formation of lactic acid, but that accounts for the properties of differentiated life. He believed that it was the movement of electrons in the cell substance that animated cells, and that in the living state there are characteristic differences in the force with which the cell substance manages its electronic system. In the primitive, dedifferentiated state, pyruvic acid is the electron acceptor, turning into lactic acid, and in the fully differentiated state, oxygen is the more powerful electron acceptor, making possible a more intense energy flow (through several intermediate steps), at higher voltage.

### Source 8 — Ask the Herb Doctor: The Metabolism of Cancer

Ray Peat · Interview · Jul 15, 2016

> ## Cancer, Excitation, and Oxygen
>
> **Sarah Murray:** So it's a backup mechanism? When the body isn't using oxygen properly, it converts to using sugar inefficiently, creating waste and over-exciting the cell?
>
> **Ray Peat:** Yes. When it is either deficient in oxygen or overstimulated so that it uses up all the oxygen, it is the same thing as suffocating. There is no oxygen to turn off the production of lactic acid. The lactic acid itself is an irritant and stimulant. It shifts the cell away from the use of oxygen towards the production of more lactic acid.
>
> **Sarah Murray:** It’s a vicious cycle.
>
> **Ray Peat:** Lactic acid produces an imbalance in the electrons. It takes up some electrons to be formed, but in the process, it increases the alkalinity inside the cell. It creates a circle of more electrons than it can take up. One way the cancer cell tries to return to normal is to use those excess electrons—that can't be consumed by converting pyruvic acid to lactic acid—to synthesize fat. Interestingly, the cancer cell turns on the enzymes that synthesize fat as a way to drain away more electrons. Then, as oxygen becomes available, the respiratory process will burn fat. So, the cancer cell is eating all the sugar it can get, tearing down the body's tissue to use amino acids, and converting the energy from glycolysis to fat. It then oxidizes the fat with whatever oxygen it has. Oxidizing fat is less efficient regarding oxygen use, so it adds to the problem of oxygen deficiency.

### Source 9 — #367 Cancer pt2. Inflammation, Metabolism, & Ozempic. With Georgi Dinkov & Alannah Connealy.

Georgi Dinkov · Interview · Mar 29, 2025

> **Georgi Dinkov:** keeping that machinery takes energy, the cells will simply become more effective and say, why am I keeping this energetically expensive machinery in the form of all these proteins involved in oxidative phosphorylation? I'm going to get rid of it and start producing energy the dirty, cheap way, which is glycolysis. So really, glycology is like the coal plant, while the oxidative phosphoration is like the, I don't want to say nuclear plant because there's a bad connotation, but in terms of efficiency, that's really the comparison. So let's say we'll go back to coal burning, which creates a lot of bad byproducts. It really doesn't produce that much energy compared to per unit of raw material used compared to, let's say, the nuclear power plant, putting radiation aside completely in terms of efficiency. And that's really cancer. The cancer metabolism is that excessive glycolysis, overproduction of lactic acid, and then really lack of complete oxidation of glucose to carbon dioxide in water, which is what happens when you're using oxygen properly. Combined with that, we also see in cancer patients, insulin resistance, which should immediately kind of like, you know, if there's an endocrine doctor there, he or she should immediately think, okay, there's an oversupply of fatty acids because we now know that is the fatty acids that are causing the insulin resistance. It's not the sugar. Yes, the sugar is being wasted. And because the sugar is wasted in the cancer cell, the cancer cells increase their uptake of sugar to compensate for the perceived lack of it because they don't oxidize it properly. So a common test for cancer is to inject radioactive glucose solution into a patient and then put them in a PT scan and then see which part of the body starts to light up because that means that part is really uptaking a lot more glucose than the rest. And because the glucose is radioactive, they can pinpoint it. That usually means there's a tumor there.

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