# Cholesterol

Category: Metabolism

In animals, cholesterol is the basic sterol molecule, which is massively converted into other substances, including the steroid hormones. Thyroid hormone and vitamin A are required for this conversion.

11 passages · 1 author · 2007–2025 · Most-cited: [Ray Peat](https://bioenergeticoracle.com/md/voices/ray-peat/index.md)

Canonical page: https://bioenergeticoracle.com/concepts/cholesterol

## Synthesis

**Cholesterol** is the fundamental sterol molecule in animals, serving as the essential raw material that is massively converted into steroid hormones, a process requiring **thyroid hormone** and **vitamin A**. [Source 1] Peat argued that cholesterol is not merely a membrane component but is distributed throughout the cell, associated with chromosomes and the *cytoskeleton*, where it stabilizes structure and enables normal cell division. [Source 3] He emphasized that cholesterol acts as a broad-spectrum protective substance, an *anti-stress hormone* that can neutralize toxins and protect red blood cells from disintegration under stresses like hyperthermia. [Source 5, 9]

The synthesis and regulation of cholesterol are intimately tied to metabolic rate. Peat explained that hypothyroidism directly causes serum cholesterol to rise as metabolism slows, and that thyroid supplementation normalizes it by facilitating the conversion of cholesterol into protective steroids and bile salts. [Source 5] He noted that a healthy liver, given adequate energy from sugars and minerals, can produce sufficient cholesterol, and that dietary intake has little effect on blood levels in healthy individuals. [Source 7] When an organism is stressed, cholesterol elevates adaptively to provide the precursor for **pregnenolone** and downstream defensive steroids; a chronically high level often indicates a *conversion issue* where the thyroid-driven transformation into these hormones is impaired. [Source 9, 11]

Peat consistently challenged the dogma that high cholesterol is a primary cause of disease, citing evidence that it is protective for longevity and cognition. He referenced a nursing home study where the optimal cholesterol for longevity was **270 mg/dL**, and the Framingham study showing that levels below 200 mg/dL after age 50 were associated with a sharply higher incidence of dementia. [Source 3, 7, 11] He pointed out that the inflammatory nature of atherosclerosis was clear to early pathologists, and that the real culprit in plaque formation is the oxidation of **polyunsaturated fatty acids (PUFA)**, whose breakdown products attract macrophages and degrade the ABCA1 protein responsible for cholesterol removal. [Source 6, 10] The "foam cells" in plaques are filled with oxidized lipids, not simply cholesterol. [Source 10]

The lipoprotein carriers of cholesterol have been mischaracterized by mainstream medicine. Peat stated that **LDL**, often labeled "bad cholesterol," is extremely good because it serves as the direct source for producing **progesterone** and **DHEA**. [Source 4] He noted that the HDL/LDL ratio suggesting freedom from heart disease conversely suggests susceptibility to cancer, and that deliberately interfering with cholesterol synthesis with drugs like statins is biologically catastrophic, as it makes it impossible to produce essential brain steroids. [Source 4, 8, 11] Early trials of cholesterol-lowering interventions were halted when they revealed increased cancer mortality in the treatment groups. [Source 8]

At a cellular level, cholesterol functions as both a *lubricant* and a stabilizer of the protoplasmic solution, decreasing cell rigidity by increasing protein mobility. [Source 10] It is essential for the organized interactions between DNA and the nuclear matrix; experimental cholesterol starvation arrests cell division in a tetraploid state, a precursor to aneuploidy and cancer. [Source 2] In the brain, excitatory stimulation lowers cholesterol, while meaningful environmental enrichment increases it, and the age-related accumulation of **cholesterol esters** at the expense of free cholesterol contributes to neurodegeneration. [Source 2] Peat concluded that cholesterol's physiological meaning touches on movement, stability, differentiation, memory, and sensitivity—essentially everything physiological. [Source 6]

## People also ask

### How does thyroid function affect cholesterol levels?

Peat argued that hypothyroidism directly causes serum cholesterol to rise because a slowed metabolism fails to convert cholesterol into protective steroids and bile salts, while thyroid supplementation normalizes it by facilitating that conversion.

### Why did Peat consider LDL to be beneficial rather than harmful?

Peat stated that LDL is extremely good because it serves as the direct source for producing essential protective steroids like progesterone and DHEA, and that interfering with its synthesis using statins is biologically catastrophic.

### What role does cholesterol play in protecting cells during stress?

Peat described cholesterol as a broad-spectrum anti-stress hormone that stabilizes cell structure, protects red blood cells from disintegration under stresses like hyperthermia, and provides the precursor for defensive steroids such as pregnenolone.

## Related concepts

- [Cholesterol (HDL, LDL)](https://bioenergeticoracle.com/md/concepts/cholesterol-hdl-ldl/index.md)
- [Free Fatty Acids (FFAs, NEFA)](https://bioenergeticoracle.com/md/concepts/free-fatty-acids-ffas-nefa/index.md)
- [Adrenaline](https://bioenergeticoracle.com/md/concepts/adrenaline/index.md)
- [Age Pigment (Lipofuscin)](https://bioenergeticoracle.com/md/concepts/age-pigment-lipofuscin/index.md)
- [Albumin](https://bioenergeticoracle.com/md/concepts/albumin/index.md)
- [Aldosterone](https://bioenergeticoracle.com/md/concepts/aldosterone/index.md)

## Cited passages

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

### Source 1 — Glossary

Ray Peat · Glossary

> Cholesterol
>
> In animals, cholesterol is the basic sterol molecule, which is massively converted into other substances, including the steroid hormones. Thyroid hormone and vitamin A are required for this conversion.

### Source 2 — Cholesterol in Context Part II: A Formative Medium

Ray Peat · Newsletter · 2018

> Within the cell nucleus, there is a highly organized substance, the nuclear matrix, that interacts closely with the rest of the cytoskeleton, permitting DNA to be expressed according to the cell’s need as it responds to its environment. Cholesterol and other lipids are essential for the specific highly organized interactions between DNA and the rest of the cell (Albi and Villani, 2009). When cultured cells are experimentally “cholesterol starved” they are unable to complete the mitotic process, and are arrested in a tetraploid state, with twice the normal number of chromosomes (Martínez-Botas, et al., 1999). In this arrested state they are unstable and, if cell division resumes, likely to form aneuploid (abnormal number of chromosomes) cancer cells. The tetraploid state becomes frequent in aging skin; one of the effects of ultraviolet light is to inhibit the formation of cholesterol. Aging and premature death of the skin cells is a better outcome than cancerization; both can be produced by cholesterol deprivation.
>
> Cholesterol is involved in the maintenance of stem cells and the control of their maturation into functioning cells. A “cholesterol chelator,” cyclodextrin, which interferes with cellular cholesterol, causes cardiac stem cells to mature into functioning heart muscle cells: “β-CD performed its function by increasing the free intracellular cholesterol” (Shi, et al., 2017). Another group using a cyclodextrin to reduce the accumulation of the age pigment lipofuscin, found that the cyclodextrin increased cholesterol synthesis (Gaspar, et al., 2017). Excitatory transmission appears to contribute to the loss of cholesterol in the brain during aging; the amount of cholesterol in synapses decreases with aging (Sodero, et al., 2011). Although excitatory (glutamatergic) stimulation lowers brain cholesterol, environmental enrichment (meaningful experience) increases it (Levi, et al., 2005), and also reverses the age-related decline in the neurosteroids derived from cholesterol (Rossetti, et al., 2015).
>
> In the brain, the accumulation of cholesterol esters (at the expense of free cholesterol) increases with age and contributes to neurodegeneration.

### Source 3 — Cholesterol Is an Important Molecule KMUD 2008

Ray Peat · Interview · 2008

> **Herb Doctor:** I know that you are very keen to emphasize the nutritional side of a person's lifestyle, rather than simply prescribing drugs or even herbal supplements. In relation to diet, i know the topic of high cholesterol is a fairly touchy subject, given that many (if not most) of the statin drugs have been implicated in causing severe side-effects. What’s your opinion on the cause of high cholesterol? And how high a cholesterol value do you consider high? And how would you approach it’s treatment?
>
> **Ray Peat:** There was a study a few years ago of women in nursing homes, or rest homes, or convalescent hospital situations, and they followed them from the time they entered until they died and watched how the level of cholesterol corresponded to their longevity and ability to function. The optimal cholesterol level for that purpose, living a long time and keeping their mentality sound, was 270 mg/dl.
>
> **Herb Doctor:** The current laboratories and doctors recommend that it should be under 200.
>
> **Ray Peat:** There was a Framingham study, I think it was about 20 years ago, which looked at the cholesterol level of people as they passed the age of 50, in ordinary life situations. And they saw that those who did not have above a 200 mg/dl cholesterol level were more likely to become demented. It's been known for 80 or 90 years that cholesterol is an antitoxin, anti-inflammatory, basic protective substance. It's like a protective hormone in the cell. In experiments with animals, the learning ability, and the measurable ability of the animal improves, just by increasing the amount of cholesterol. And cell division involves cholesterol right in the apparatus that allows the cell to divide normally. It stabilizes red blood cells. Every level of physiology is protected by adequate cholesterol.

### Source 4 — Glossary

Ray Peat · Glossary

> Cholesterol (HDL, LDL)
>
> HDL and LDL are often called "good cholesterol" (High Density Lipoproteins) and "bad cholesterol" (Low Density Lipoproteins) because of a slight association between their ratio and heart disease, but in fact the ratio that suggests freedom from heart disease suggests susceptibility to cancer. LDL ("bad") is extremely good because it is used as the source for producing progesterone and DHEA.

### Source 5 — Cholesterol in Context: Part I

Ray Peat · Newsletter · 2018

> # Cholesterol in Context: Part I
>
> “Twenty morons at the right places can kill a science.” — Erwin Chargaff, quoted by Gilbert Ling*
>
> I decided to write about cholesterol again because the U.S. government and most medical doctors continue to say absurd things about it. Individuals can protect themselves by refusing to swallow their toxic misinformation, but our common environment is being degraded in many ways by the consequences of this massive deception.
>
> It’s useful to know something of the forces that have gone into creating the cholesterol demon of popular culture, but the essential thing is to recover the main line of investigation of cholesterol’s role in the development of life and consciousness.
>
> According to an old edition of W.G. MacCallum’s pathology textbook, “It has been shown that certain lipoid substances, especially cholesterine, can act as inhibiting or neutralizing agents toward such haemolytic poisons as saponin, cobra poison, etc., through forming with them an innocuous compound. Hanes showed that the relative immunity of puppies from chloroform poisoning is due to the large amount of cholesterin esters in their tissues. When artificially introduced into the tissues of adult animals a similar protection is conferred.”
>
> Several people in the 1930s and ’40s showed that hypothyroidism caused atherosclerosis, and thyroid supplementation corrected it. In people whose thyroid gland was removed, their serum cholesterol increased as their rate of metabolism slowed, and when they were given desiccated thyroid to normalize their metabolic rate, their serum cholesterol was immediately correspondingly normalized. In the early 1930s, Broda Barnes showed that heart disease developed in hypothyroid people, not in people whose metabolism was properly maintained by the thyroid hormone.
>
> Later, many experimenters, building on older observations, showed that the rising cholesterol had a defensive function. For example, when the amount of cholesterol flowing into an ovarian artery was increased, the amount of progesterone flowing out of an ovarian vein increased proportionally, as the raw material was converted to the product. A major function of the thyroid hormone is the conversion of cholesterol into steroid hormones, including the “bile salts,” but that function has to be considered in relation to structural and energetic processes that are affected by both thyroid and cholesterol.
>
> Since then, numerous publications have described cholesterol’s effect in protecting red blood cells from factors that would normally cause them to disintegrate.

### Source 6 — Cholesterol, longevity, intelligence, and health.

Ray Peat · Article · 2007 · https://raypeat.com/articles/articles/cholesterol-longevity.shtml

> I suspect that the physiological meaning of cholesterol has to do with movement, stability, differentiation, memory, and sensitivity of the parts of the cells, that is, with everything physiological.
>
> The functions of cholesterol parallel the functions of other sterols in plants and other types of organism. Its functions have been refined and extended with the development of other steroids, such as progesterone, as biological requirements have evolved, but cholesterol is still at the center of this system.
>
> To deliberately interfere with its synthesis, as contemporary medicine does, reveals a terrible arrogance. Many participants in the cholesterol-lowering cult believe that they have succeeded in hijacking our science culture, but when the patents on another generation of their drugs have expired, the cult could begin to fade away.
>
> [references]

### Source 7 — Politics & Science: Empiricism vs Dogmatic Modeling

Ray Peat · Interview · Jul 24, 2008

> **John Barkhausen:** We are speaking with Ray Peat out in Eugene, Oregon. He's an endocrinologist and physiologist who has written a lot of books about health, nutrition, and science, and publishes *Ray Peat's Newsletter*. You can find him on the web at raypeat.com. Just yesterday we were doing a sound check and we picked up where we left off last week, talking about fats in our diet and the use of fats by humans over the years and as animal feed. You were talking about cholesterol and mentioned a fellow named Chris Masterjohn. One of the things you said that shocked me was that for years we've heard that cholesterol is something you get from fat—from butter, beef fat, or meats full of supposedly saturated fats—and that's why we're being poisoned by cholesterol. But it turns out that perhaps cholesterol isn't the boogeyman we always thought it was. It's actually something we need to function.
>
> **Ray Peat:** Yes, but regarding eating cholesterol: if you're healthy, you have to eat a tremendous amount to raise your levels. There was an experiment where they had healthy young men eat eggs until they could see an increase in blood cholesterol. It took 22 eggs before they saw a rise in the day's cholesterol. It does rise if you're very sick and can't compensate. In a practical situation where a person might want to raise their cholesterol, you can usually do it just by eating lots of fruit. The minerals and sugar in the fruit give the liver the energy it needs to make adequate cholesterol. There is a U-shaped curve of mortality. You have an ideal range of cholesterol for a given age, and when you're below that range, your mortality increases.

### Source 8 — Dogmatism in Science (Politics & Science, 2008)

Ray Peat · Interview · Jul 24, 2008

> **John Barkhausen:** What are those ranges?
>
> **Ray Peat:** The published – the people who talk about the curve – usually put the bottom of the U around 160 to 180, but when you look at the figures, the bottom really varies with age. Like one study looked at people in a nursing home situation, and saw that the ones who had the highest cholesterol, I think in that group, those with 270 lived the longest. So you have to think about the relation of the cholesterol to the stress you’re under, and consider it an anti-stress hormone.
>
> **John Barkhausen:** My father recently was told that he has to start taking statins, and a lot of people are on statins. What’s your opinion?

### Source 9 — Ray Peat Full Interview: Cholesterol, PUFA, Coconut Oil, Thyroid, and the Metabolic Truth

Ray Peat · Interview · Jul 12, 2025 · https://www.youtube.com/watch?v=lQB95tLW7eE

> **Ray Peat:** They would give a lethal dose of the poison to an animal, and if they gave it a good dose of cholesterol, it would survive an otherwise lethal dose. And that has been done repeatedly. There have been some more specific things For example, the testes are stimulated to more efficiently produce sperms in the presence of cholesterol, and the cholesterol has a direct activating effect on producing more of the defensive steroids and helping the cell do what it should do, as well as interfering with the the toxic effects of chemical stresses and physical stresses. For example, hyperthermia that will cause your red cells to break down if you add enough cholesterol. The cells won't be hurt by an otherwise deadly temperature. So it's just an incredibly broad spectrum protective substance.

### Source 10 — Cholesterol in Context: Part I

Ray Peat · Newsletter · 2018

> When a drop of water is on an oily surface it doesn’t spread, because of its strong cohesive forces, and the oil’s lack of those forces. When a drop of oil falls onto water, it spreads, becoming extremely thin. Benjamin Franklin estimated that a teaspoonful of olive oil spread over about half an acre of a pond. Oil has very weak cohesive forces, and effectively no tensile strength. The fact that cholesterol strengthens cells, keeping them from disintegrating under stress, obviously has nothing to do with a lipid bilayer membrane. That membrane doctrine has made it seem paradoxical that the loss of cholesterol should make cells stiffer, while weakening them. Gilbert Ling has, for 65 years, pointed out the numerous “paradoxes” confronted by the advocates of the lipid boundary membrane, but the membrane doctrine continues to govern most biomedical thinking, including theories of cholesterol’s role in the diseases of aging.
>
> About 40 years ago, someone noticed that the commercial cholesterol used for research was contaminated by oxidation, and that pure cholesterol didn’t produce the same toxic effects. Lipid peroxidation was observed in atherosclerotic plaques, and the breakdown products of polyunsaturated fats such as hydroxynonenal, malondialdehyde, and acrolein (from EPA, arachidonic acid, and other highly unsaturated fats in the affected blood vessel) are known to attract white blood cells such as macrophages, which accumulate in the plaques. The age pigment, ceroid or lipofuscin, that’s derived largely from PUFA and associated with the macrophage “foam cells” in the plaque, accumulates iron (Lee, et al., 1998), and by catalyzing oxidation, creates local hypoxia, leading to lactic acid production, contributing to an inflammatory process. The products of lipid peroxidation, such as azelaic acid (Riad, et al., 2018), along with lactate, lead to the calcification of tissue.
>
> Several observers have demonstrated that a protein that can remove excess cholesterol and other lipids from arteries, ABCA1 (ATP-binding cassette transporter or CERP (cholesterol efflux regulatory protein)), is degraded by polyunsaturated fatty acids.

### Source 11 — One Radio Network: Nothing is as it seems with COVID (July 20, 2020)

Ray Peat · Interview · Jul 20, 2020

> **Patrick Timpone:** Interesting. What would be, is there such a thing as like the perfect cholesterol number? I mean, the big number that everybody talks about, you know, 180, 200, or do you have a fave number that you kind of like to see?
>
> **Ray Peat:** Oh, it depends on your age. The Framingham study found that basically no one who had their cholesterol well over 200, very low incidence of dementia if they kept their cholesterol up over the age of 50. But those who were below 50, 200 had an extremely high dementia incidence. That's explained because your gonads and adrenals depend on the amount of cholesterol in the blood for making the protective steroid hormones. In an experiment with an isolated ovary, for example, they measured keeping the thyroid hormone level. They measured the amount of progesterone coming out of the vein from the ovary, and they varied the amount of cholesterol going into the artery to the ovary. And as they increased the cholesterol in the blood going in, the amount of progesterone coming out of the ovary corresponded and increased. So rising cholesterol is adaptive, keeping your brain steroid hormones up, keeping your ovarian systemic hormones up, your adrenal hormones, everything. Your brain especially depends on the adequate amount of cholesterol in the blood. And if you're Thyroid is low. That means you require more cholesterol in the blood to keep your brain supplied with steroids. And so hypothyroid people properly and adaptively have a proportionally high cholesterol.

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