# Myelination

Category: Metabolism

Myelin is a multilayered enclosure of the axons (the long processes) of nerve cells, composed of proteins and complex lipids, including cholesterol. The layered material is a flat, thin extension of the cytoplasm of the oligodendroglial cells.

9 passages · 2 authors · 2009–2019 · Most-cited: [Ray Peat](https://bioenergeticoracle.com/md/voices/ray-peat/index.md)

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

## Synthesis

**Myelination** is the process by which **oligodendrocytes**—glial cells with sheet-like processes—wrap themselves in thin layers around the conductive axons of nerve cells, forming a multilayered enclosure called myelin composed of proteins and complex lipids, including **cholesterol**. [Source 1, 2] This process is fundamentally dependent on **thyroid hormone**; oligodendrocytes absorb T3 under the influence of thyroid, and their absorption is promoted by *butyrate*, an anti-stress substance found in butter and coconut oil. [Source 2] Peat argued that thyroid is responsible for both myelination and hormone formation, and that in conditions like multiple sclerosis, the problem is specifically with myelination rather than with the nerve cells themselves. [Source 5]

Peat rejected the standard textbook view that myelin functions primarily as an electrical insulator enabling *saltatory conduction*, calling this idea a "fetish" that obstructed progress in biology. [Source 4] Instead, he emphasized that oligodendrocytes are **steroid-synthesizing** cells that produce *pregnenolone* when activated, and he considered it obvious to ask whether their local production of pregnenolone in response to stress or fatigue is relevant to the conduction processes of the nerves they surround. [Source 2, 4] The brain's white matter is extremely rich in cholesterol, and maintaining sufficient energy—through sugar, thyroid, and progesterone—is necessary to synthesize cholesterol and myelin fast enough. [Source 7] Stress activates enzymes that attach fatty acids to cholesterol, forming esterified cholesterol, a process promoted by estrogen and associated with tissue deterioration. [Source 7]

The breakdown of myelin, according to Peat, is driven by a chronic, slight *energy deprivation* that causes tissue edema. [Source 6] When energy is low—for example, when thyroid is deficient—cells take up water and swell, and while myelin is being taken down in the normal turnover process, it cannot be resynthesized efficiently because the organism cannot make sufficient pregnenolone and progesterone. [Source 6] **Thyroid, progesterone, and pregnenolone** are all involved in the formation of new myelin and in the prevention of the edema that damages it, while saturated fatty acids also support myelin reformation. [Source 6, 8] The methylation pathway is additionally involved in making the myelin coating of nerves, with a substantial portion of the body's methylation capacity directed toward synthesizing creatine for cellular energy. [Source 9]

Peat connected myelination to broader developmental and degenerative processes. He noted the historical, erroneous belief that babies do not experience pain before myelination is complete around 18 months, a view he considered a form of "mind blindness" or autism-like lack of empathy. [Source 3] In old age, brain steroids fall to about 5% of their youthful levels, yet glial cells become more numerous and myelin formation typically continues without problem, unlike in multiple sclerosis where myelination specifically fails. [Source 5] This suggested to Peat that Alzheimer's disease might involve a specific premature loss of brain pregnenolone production, while MS involves a deficiency of thyroid or of T3 within the oligodendrocytes, leaving those cells deficient in their ability to produce pregnenolone locally for the nerve fibers they surround. [Source 5]

## People also ask

### How does thyroid hormone affect myelination?

Peat argued that thyroid hormone is fundamentally necessary for myelination because oligodendrocytes absorb T3 under its influence, and without sufficient thyroid, these cells cannot efficiently synthesize the myelin sheath or produce local pregnenolone.

### Why did Peat reject the idea that myelin is just an electrical insulator?

Peat considered the insulator view a "fetish" that blocked progress, emphasizing instead that oligodendrocytes are steroid-synthesizing cells that produce pregnenolone when activated, which he thought was relevant to nerve conduction.

### What role does energy deprivation play in myelin breakdown?

According to Peat, chronic low energy causes tissue edema that prevents efficient myelin resynthesis during normal turnover, because the organism cannot make enough pregnenolone and progesterone to support new myelin formation.

## Related concepts

- [Multiple Sclerosis](https://bioenergeticoracle.com/md/concepts/multiple-sclerosis/index.md)
- [Oligodendrocytes](https://bioenergeticoracle.com/md/concepts/oligodendrocytes/index.md)
- [Adrenaline](https://bioenergeticoracle.com/md/concepts/adrenaline/index.md)
- [Cytochrome P450scc.](https://bioenergeticoracle.com/md/concepts/cytochrome-p450scc/index.md)
- [Glial](https://bioenergeticoracle.com/md/concepts/glial/index.md)
- [Thymus Gland](https://bioenergeticoracle.com/md/concepts/thymus-gland/index.md)

## Cited passages

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

### Source 1 — Glossary

Ray Peat · Glossary

> Myelination
>
> Myelin is a multilayered enclosure of the axons (the long processes) of nerve cells, composed of proteins and complex lipids, including cholesterol. The layered material is a flat, thin extension of the cytoplasm of the oligodendroglial cells.

### Source 2 — Multiple Sclerosis and Other Hormone-Related Brain Syndromes

Ray Peat · Article · 2013 · https://raypeat.com/articles/articles/multiple-sclerosis-hormone-related-brain-syndromes.shtml

> 2. Cytochrome P450scc. The cytochromes are \"pigments,\" in the same sense that they contain the colored \"heme\" group that gives hemoglobin its color. P450 means \"protein that absorbs light at a wavelength of 450. The scc means \"side-chain cleaving,\" which refers to the removal of the 6 carbon atoms that distinguish cholesterol from pregnenolone. Other Cyt P450 enzymes are important for their detoxifying oxidizing action, and some of these are involved in brain metabolism.
> 3. Glial means \"glue-like,\" and glial cells are mostly spidery-shaped cells that used to be thought of as just connective, supportive cells in the brain.
> 4. Mitochondria (the \"thread-like bodies\") are the structures in cells which produce most of our metabolic energy by respiration, in response to the thyroid hormones.
> 5. Mucoid--refers to a mucoprotein, a protein which contains some carbohydrate. A glycoprotein; usually not intended as a precise term.
> 6. Myelination. Myelin is a multilayered enclosure of the axons (the long processes) of nerve cells, composed of proteins and complex lipids, including cholesterol. The layered material is a flat, thin extension of the cytoplasm of the oligodendroglial cells.
> 7. Oligodendrocytes are one of the kinds of glial (or neuroglial) cells, and structurally they are unusual in having sheet-like, rather than just thread-like processes; they have a sensitivity (\"receptors\") to stress and valium, and produce pregnenolone when activated. Under the influence of thyroid hormone, they wrap themselves in thin layers around the conductive parts of nerve cells, leaving a multilayered \"myelin\" coating. Their absorption of thyroid hormone is promoted by butyrate, an anti-stress substance found in butter and coconut oil.
> 8. Steroidogenesis is the creation of steroids, usually referring to the conversion of cholesterol to hormones.

### Source 3 — Autism and Causality

Ray Peat · Newsletter · 2018

> This is sometimes called mind blindness, or emotion blindness.
>
> When I was in graduate school, a psychology professor told me that the reason babies don’t need anesthesia during surgery is that, before myelination in their brain is complete around the age of 18 months, they don’t experience pain. A biology professor said that we can’t know that animals experience pain because they can’t speak. Many years before that, Sigmund Freud had written that without language, there is no consciousness. In the US in the 1990s, a survey found that the great majority of circumcisions were performed without any anesthetic; the usual explanation was either that it didn’t cause pain, or if it did, the baby didn’t remember it. I always understood that my professors, and a large proportion of the medical and scientific professions, suffered from some sort of mental defect, but I didn’t have a name for it. Now I understand that it is a form of autism, mind blindness. Without a recognition of another’s mind, there can be no empathy.
>
> > Touch is ten times stronger than verbal or emotional contact, and it affects damn near everything we do.
> >
> > — Ashley Montagu
>
> It used to be common for doctors to tell new mothers that babies shouldn’t be picked up whenever they cried, and nursery workers are still often instructed to minimize physical contact with the babies, and formula feeding, with early weaning, has been promoted by most doctors, and is still the rule in the US and several other countries. Several studies have shown a decline in the empathy of medical students in their third year, when they begin taking care of patients; the stress of excessively long hours of work is probably a factor. Studies of beginning college students have shown much lower empathy levels (or at least an increased willingness to express their lack of empathy) than in previous generations, suggesting that something is happening in the culture to make a lack of empathy more socially acceptable. By many of the accepted definitions of autism, the medical profession fosters autism, and our general culture is becoming more autistic.
>
> In the family of defining features of autism—mind blindness, communicative difficulty, lack of eye contact, avoidance of physical contact with people, repetitive movements, narrow interests, reduced understanding of the continuing succession of events—there is a common factor, namely, inflexibility.

### Source 4 — Multiple Sclerosis and Other Hormone-Related Brain Syndromes

Ray Peat · Article · 2013 · https://raypeat.com/articles/articles/multiple-sclerosis-hormone-related-brain-syndromes.shtml

> It is easier to study the myelin sheath in peripheral nerves, and the electrical activity of a nerve is the most easily studied aspect of its physiology. Certain experiments seemed to indicate a \"jumping\" (saltatory) kind of conduction along the nerve between Schwann cells, and it was argued that the insulating function of the myelin sheath made this kind of conduction possible. This idea has become a standard item in physiology textbooks, and its familiarity leads many people to assume that the presence of myelin sheaths in the brain serves the same \"insulating\" function.
>
> For a long time it has been known that heat production during nerve conduction reveals a more continuous mode of conduction, that doesn't conform to the idea of an electrical current jumping around an insulator. Even if the myelin functioned primarily to produce \"saltatory conduction\" in peripheral nerves, it isn't clear how this process could function in the brain. I think of the issue of \"saltatory conduction at the nodes of Ranvier\" as another of the fetish ideas that have served to obstruct progress in biology in the United States. A more realistic approach to nerve function can be found in Gilbert Ling's work. Ling has demonstrated in many ways that the ruling dogma of \"cell membrane\" function isn't coherently based on fact. He found that hormones such as progesterone regulate the energetic and structural stability of cells. Many people, unaware of his work, have felt that it was necessary to argue against the idea that there are anesthetic steroids with generalized protective functions, because of their commitment to a textbook dogma of \"cell membrane\" physiology.
>
> I think the myelinating cells do have relevance to nerve conduction, but I don't think they serve primarily as electrical insulators. If the adrenal cortex were inside the heart, it would be obvious to ask whether its hormones aren't important for the heart's function. Since the oligodendrocytes are steroid-synthesizers, it seems obvious to ask whether their production of pregnenolone in response to stress or fatigue isn't relevant to the conduction processes of the nerves they surround.
>
> ## OLD AGE
>
> A biologist friend of mine who was about 85 became very senile. His wife started giving him thyroid, progesterone, DHEA and pregnenolone, and within a few days his mental clarity had returned.

### Source 5 — Multiple Sclerosis and Other Hormone-Related Brain Syndromes

Ray Peat · Article · 2013 · https://raypeat.com/articles/articles/multiple-sclerosis-hormone-related-brain-syndromes.shtml

> Thyroid is responsible for both myelination and hormone formation. In old age, glial cells become more numerous, and nerve cells become structurally and functionally abnormal, but usually there is no problem with the formation of myelin. In MS, the problem is just with myelination, and there are no senile plaques or defects in the nerve cells themselves.
>
> These differences suggest the possibility that Alzheimer's disease involves a specific premature loss of brain pregnenolone production, but not of thyroid. Recent work suggests a central role for pregnenolone and progesterone in the regulation of consciousness (18), and possibly in the brain's detoxifying system. Elsewhere, I have suggested that vitamin A deficiency might cause the excessive production of the \"amyloid\" protein. A vitamin A deficiency severely inhibits steroid synthesis. (It is used so massively in steroid synthesis that a progesterone supplement can prevent the symptoms of vitamin A deficiency.) I suspect that vitamin A is necessary for the side-chain cleavage that converts cholesterol to pregnenolone. Iron-stimulated lipid peroxidation is known to block steroid formation, and vitamin A is very susceptible to destruction by iron and oxidation. Iron tends to accumulate in tissues with aging. Gajdusek has demonstrated that brain deterioration is associated with the retention of whatever metal happens to be abundant in the person's environment, not just with aluminum. (One type of glial cell is known for its metal-binding function, causing them to be called \"metallophils.\"). According to Gajdusek, \"calcium and other di- and trivalent elements\" are \"deposited as hydroxyapatites in brain cells\" in brain degeneration of the Alzheimer's type. (19)
>
> Even early forms of Alzheimer's disease begin at an age when the youth-associated steroids have begun to decline. If MS involves a deficiency of thyroid (or of T3 within the oligodendrocytes, where T3 normally can be made from thyroxine; many things, including protein deficiency, can block the conversion of T4 to T3), those cells would necessarily be deficient in their ability to produce pregenolone, but in young people the brain would still be receiving a little pregnenolone, progesterone, and DHEA from the adrenals and gonads.

### Source 6 — Politics Science Autoimmune Diseases and Movement Disorders

Ray Peat · Interview · 2012

> **John Barkhausen:** So, let's use an example of one of these diseases, like multiple sclerosis: the myelin sheath for some unknown reason, according to the medical authorities, becomes worn away or taken away and the nerves stop functioning and people start having trouble with motor control; they say it's caused by inflammation. How does that relate to your idea?
>
> **Ray Peat:** Anything that causes a lack of energy will cause tissue to swell up, take up water and as it swells up the tissue tries to renew itself. Cells are always renewing themselves in a tremendous churning process of taking down the old stuff and putting up new stuff. For example, someone said that during the night, I think it was 60% of our molecules in our brain, the fat substance, that consists a big part of the brain, 60% of them are totally resynthesized every night. And just an hour after death, a massive amount of the brain substance has decomposed because it isn't constantly being reconstituted. So you have to think in terms of a healthy stable organism as being in extremely intense turnover processes. So if you cut off the energy supply, the first thing that happens is the cell takes up water and that excites the restorative process to run faster. But if it takes up more and more water, that shifts the whole direction and the cells at a certain stage of excitation will de-differentiate and try to turn into a stem cell, to grow new tissue as a healing process. If there's even less energy, then that process stops. When you have just a chronic, slight energy deprivation, you get a chronic slight edema and that edema, one of the things that happens is that the myelin swells up, and while it’s being taken down it isn't being resynthesized efficiently. Thyroid, progesterone, pregnenolone and saturated fatty acids are things that support the reforming of the myelin. And when the energy is down — for example, thyroid is low — then you can't make the pregnenolone and progesterone and so you just can't synthesize it as fast as it’s being taken down.

### Source 7 — KMUD Herb Doctors — April 18, 2014 (partial recording)

Ray Peat · Interview · Apr 18, 2014

> **Caller:** Okay. Thank you so much.
>
> **Andrew Murray:** You're very welcome. Okay, I think there was another caller on the air. No, okay. The caller's gone. Okay, Dr. Peat, I've got another question for you, and it's about cholesterol. I know you've mentioned in the past that the free, the free, Not three, but a free form of cholesterol is good. And the esterified form is destructive, particularly with reference to Alzheimer's and what goes on in the brain of the Alzheimer's patient. But what causes this cholesterol to become esterified? And how is myelin, which comprises the nerve sheath, and so important to proper nerve signaling, made?
>
> **Ray Peat:** Sugar and thyroid and progesterone are... And often the limiting factors in making myelin fast enough and sugar in the system in general helps you make cholesterol. Keeping the energy up is necessary to make enough cholesterol. And the cholesterol is a stabilizing factor for every aspect of the cell, cell division. multiplication, ion regulation, and so on. And it happens that the myelin is especially rich in cholesterol. But apparently stress activates enzymes that attach fatty acids to the cholesterol as possibly some kind of adaptive reaction for changing the rate of cholesterol synthesis maybe. Anyway, estrogen is one of the factors that promotes the combination with fatty acids. The fact that so few animals are given a diet low in unsaturated fats, that has influenced the research on trying to explain what the ester form of the cholesterol means. Because when we find that, for example, if you look at an atheroma in a hardening artery, as it begins to form, there's only a little of the ester form of cholesterol. But as it ages and advances and becomes more destructive to the artery, the concentration of linoleic acid attached to the cholesterol increases progressively with deterioration and aging. And the research just hasn't been interested in looking at animals that are deprived of unsaturated fats to see if they would even form the atherosclerotic plaque at all. Many of the degenerative changes are extremely delayed when animals are made deficient in the so-called essential fatty acids. For example, in relation to diabetes, several experimenters have created... a technical deficiency of essential fatty acids by giving them a diet containing almost no linoleic or arachidonic acid. And then they poison them with the standard chemicals for creating diabetes and they're essentially impervious. They just refuse to get diabetes in the usual conditions. Their pancreas is so resistant.

### Source 8 — Multiple sclerosis, protein, fats, and progesterone

Ray Peat · Article · 2009 · https://raypeat.com/articles/articles/ms.shtml

> Progesterone has some similar effects, and is protective against excess cortisol, and is a major factor in nerve and brain restoration.
>
> Thyroid, progesterone, and pregnenolone are all involved in the formation of new myelin, and in the prevention of the edema that damages it.
>
> Since thyroid and progesterone decrease the formation of estrogen in inflamed tissue, while cortisol stimulates its formation, it would seem wise to use thyroid and progesterone for their immediate antiinflammatory effects, which include the inhibition of NO formation (Drew and Chavez, 2000), and their lack of the excitotoxic, estrogen-stimulating effects of the glucocorticoids.
>
> While the glucocorticoids are catabolic and liberate cysteine and tryptophan from muscles, thyroid and progesterone are not catabolic, and protect against the toxic consequences of those amino acids.
>
> [references]

### Source 9 — #13: Bioenergetic Concepts in Sport and Exercise, Fast Twitch Muscles, and Methylation in Context

Danny Roddy · Interview · Oct 6, 2019 · https://open.spotify.com/episode/1FQYkLEy0nAMYwh92J5r4F

> **Danny Roddy:** Let's step back for a second. What is methylation? Why is it important?
>
> **Nick:** Yeah, so it's just like... You could consider energy metabolism and the citric acid cycle as one pathway in the body that we've delineated where making energy is the main goal of that. Methylation is named because it involves the transfer of methyl groups between molecules. But it's a pathway that's involved in in making creatine, in making the myelin coating of your nerves, in DNA and RNA and all these other things that our body needs. And especially on even tying it more purely to energy metabolism, like creatine is a source of immediate energy in your cells. 60 to 80% of the capacity for methylation just goes towards making creatine. And so if you... Are you good?
>
> **Danny Roddy:** Can you still see me and hear me? Oh, there you are. Can you see me?
>
> **Nick:** Yeah, you're just breaking up a little bit there. Yeah. But if you... Yeah, if you ignore the things you need for that pathway, then... then you're diminishing your ability to make energy in sort of a cheap and effective way. And we also talked about, this was one of the weird issues I inflicted on myself, but there are some talks of the dangers of iron. And I also think it's beneficial to donate blood, but it's a really good way to cut off your... ability to supply oxygen and energy to the cells in your body is to become anemic. And sort of some of the classical things involved with red blood cell production are the nutrients involved in methylation, cells that are proliferating very quickly, the blood cells in your bone marrow. It's B6 and B12 and B9 and B2.

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