Ray Peat on aging

December 4, 2025

Young vs. aging brain – cholesterol

"The healthy young brain contains a very large amount of cholesterol, almost entirely in its pure, non-esterified or free form – more than 99.5%, according to Orth and Bellosta (2012, cited in Bjorkhem and Meaney, 2004). The aging, degenerating brain contains an increasing amount of esterified cholesterol."

– September 2018 – Ray Peats Newsletter

Nighttime parathyroid hormone activity and calcium loss

"During the night, parathyroid hormone levels normally rise (Radjaipour 1986; Logue 1989, 1990; Fraser 1998), and especially in old age, this leads to a significant loss of calcium from the bones. Consuming a large portion of the daily calcium intake before bedtime reduces the nocturnal rise in PTH and the calcium loss from the bones."

– September 2017 – Ray Peats Newsletter

Hair loss as an indication of metabolic problems

"Hair loss should be taken seriously – like obesity or high blood pressure – as an indication of a systemic metabolic problem. The metabolism of the hair follicle contains clues about aging, tissue regeneration and cancer."

– September 2017 – Ray Peats Newsletter

Benefits of coconut oil for thyroid and health

"The easily oxidizable short- and medium-chain saturated fatty acids in coconut oil provide an energy source that protects our tissues from the toxic, inhibitory effects of unsaturated fatty acids and reduces their thyroid-suppressing effect. Animal studies over the last 60 years suggest that these effects also offer protection against cancer, heart disease, and premature aging. Other anticipated effects include protection against excessive blood clotting, protection of the fetal brain, protection against various stress-related problems including epilepsy, and some protection against sun-induced skin damage."

Nutrition for Women

The role of estrogen in cellular renewal and responses to threats

"Estrogen is the hormone of new beginnings, a kind of biochemical eraser that can delete recently stored information and restore the underlying original capacity for growth. When we are threatened – by injury or aging – we need the ability to renew cells."

Nutrition for Women

The effect of estrogen on the production of prolactin and growth hormone

"Estrogen promotes the production of prolactin, a protein hormone, and its close analogue, growth hormone. Ionizing radiation, aging, and oxygen deficiency all cause biochemical changes similar to those caused by estrogen."

Nutrition for Women

The effects of estrogen on experience and memory formation

"Argumentation patterns are stabilized as knowledge and as developmental changes in tissue: growth and aging and their effects. An excess of estrogen or other factors that impair proteolysis could block the ability to experience. The difficulty in remembering dreams is probably related to this synthetic (non-proteolytic) parasympathetic dominance during sleep."

Nutrition for Women

Nutritional factors in relation to aging and reproduction

"Even in wealthy cultures, protein deficiency, inappropriate physical activity, and emotional stress contribute to premature aging of the individual and to harm to offspring."

Nutrition for Women

Estrogen, reproductive aging, and cancer theories

"This antioxidant effect of estrogen suggests that research on reproductive aging is approaching Warburg's theory that impaired respiration is the primary defect in cancer, and also Selye's observation that the effect of estrogen is similar to the initial shock phase of the stress response."

Nutrition for Women

Prevention of premature aging through essential nutrients

"All essential nutrients are constantly needed to prevent the body's decline. At various times, nutrients such as vitamin C, pantothenic acid, or vitamin E have been identified as methods for preventing premature aging. In our culture, many people have severe deficiencies in these nutrients, but any nutrient deficiency can cause degenerative changes."

Nutrition for Women

Aging and Cushing's syndrome: Fat distribution and vitamin E

"The distribution of fat is similar in old age and in Cushing's syndrome. It is known that vitamin E alters enzyme activities in such a way as to balance this distribution, and this could occur in cases caused by hormonal disorders, not just by aging alone."

Nutrition for Women

Normalization of the immune system through testosterone and progesterone

"Some of the changes associated with aging are likely related to autoimmune reactions, in which the body attacks itself; both testosterone and progesterone normalize the immune system and suppress autoimmune problems."

Nutrition for Women

The role of vitamin E in efficient oxidation and energy

"In cells, vitamin E inhibits destructive and wasteful oxidation (such as occurs in aging and cancer) and makes the normal oxidation process more efficient, so that more usable energy is provided for a given amount of oxygen."

Nutrition for Women

Importance of nutrients for mitochondrial function and aging

"In old age, the walls of blood vessels tend to harden due to calcium. In at least some tissues, calcification is known to begin in degenerating mitochondria, and mitochondria tend to degenerate in aging tissue. Nutrients such as iodine, vitamin E, magnesium, and vitamin B2 are particularly important for maintaining the function of the mitochondria, which produce the majority of our energy."

Nutrition for Women

Potential therapeutic use of thyroxine in aging, radiation sickness and cancer

"Since aging and X-rays have some biochemical effects similar to those of estrogen, they could also antagonize thyroxine; this suggests that large doses of thyroxine could be used in senility, radiation sickness, and cancer."

Nutrition for Women

Aging theory: Accumulation of racemic molecules influences biology

"An interesting theory of aging states that racemic molecules accumulate over time; these molecules are known to possess different physical and biological properties."

Nutrition for Women

The role of vitamin C in collagen synthesis and the reversal of aging processes

"One of the oldest known functions of vitamin C is its role (hydroxylation) in the synthesis of collagen for connective tissue. In high concentrations, it can also depolymerize (make more soluble) collagen, thereby reversing one of the key features of the aging process."

Nutrition for Women

Adjusting vitamin E requirements to the intake of unsaturated oils

"Unsaturated oils can also stimulate a dangerous type of oxidation, in which they degrade in a way that appears to accelerate the aging process. One of the more conservative researchers on vitamin E recently (in AJ Clin. Nutr. , 1974) revised his assessment of the required amount of vitamin E: He wrote that the requirement increases from 15 mg/day to about 50 mg/day when a person consumes a lot of unsaturated oils (fish, seeds, etc.)."

Nutrition for Women

Chemicals to maintain cellular energy charge and biological function

"Although electrical energy is closely linked to life, there are two chemicals involved in maintaining the energy charge of cells, and this energy charge is most directly related to biological function and structure. Creatine phosphate (CrP) is a kind of energy reservoir for muscles, and in the case of vitamin E deficiency, creatine leaks from the muscles. Aging also appears to be associated with deficient creatine phosphate reserves (Verzar). Adenosine triphosphate (ATP) is more directly involved in all forms of life functions, for example, maintaining the resting potential of nerves and muscles, and controlling secretion, protein retention, and the elimination of toxins."

Nutrition for Women

Reversing the effects of aging through deep slow-wave sleep

“Many of the changes caused by daily stresses are reversed during deep slow-wave sleep. The amount of slow-wave sleep decreases with age. A few animal studies have found that artificially extended sleep durations reversed some of the major problems of aging. Progesterone may increase the amount of slow-wave sleep, presumably due to its effect on body temperature.”

– November 2020 – Ray Peats Newsletter

Reduced functionality and structural changes in old age

"With aging, reduced functionality of the organism and structural changes go hand in hand."

– November 2018 – Ray Peats Newsletter

Aging skin, progesterone and vitamin D

"It has been known for several decades that the production of progesterone and DHEA steadily declines with age, and in recent years it has been found that aged skin produces only half as much vitamin D as young skin when exposed to the sun. Old skin contains about half as much cholesterol as young skin, so it is not surprising that the substances derived from it are reduced."

– November 2018 – Ray Peats Newsletter

The cholesterol content of aging skin and its appearance

"The characteristic cloudiness of aged skin is the result of an accumulation of layers of dead cells on the surface. While the vital underlying skin cells contain significantly less cholesterol than normal, the inactive cells contain an increased amount of cholesterol sulfate. When the level of free cholesterol in the skin is experimentally increased, the skin regains its ability to shed the dead superficial cells. If it is experimentally lowered, such as by a statin, the skin takes on the structure and appearance of aged skin. Aging appears to be a state of cholesterol deficiency."

– November 2018 – Ray Peats Newsletter

Excitatory signal transmission and brain cholesterol

"Excitatory signaling appears to contribute to the loss of cholesterol in the brain during aging; the amount of cholesterol in synapses decreases with age (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 cholesterol-derived neurosteroids."

– November 2018 – Ray Peats Newsletter

Methods for reducing the formation of cholesterol esters

"Besides eliminating polyunsaturated fatty acids (n-3 and n-6) from the diet to reduce cholesterol ester formation and mitigate the age-related decline in cholesterol synthesis, progesterone supplementation is one way to reduce ester formation (Synouri-Vrettakou and Mitropoulos, 1983; Miller and Melnykovych, 1984; Jeng and Klem, 1984; Mulas et al., 2011; Anchisi et al., 2012). Lidocaine is another cholesterol ester formation inhibitor (Bell, 1981; Bell et al., 1982) that is likely to be beneficial in some degenerative conditions."

– November 2018 – Ray Peats Newsletter

Urgency to revisit holism to explain developmental processes

"The holistic view of the organism and its adaptive potential, as advocated by Hippocrates and Aristotle, has been rejected by the new science of recent centuries. Reclaiming and creatively utilizing this perspective has become urgent if we want to understand the processes of development, including aging and degenerative diseases."

– November 2017 – Ray Peats Newsletter

Iron accumulation: Stress, aging and oxidative damage

"The accumulation of iron in tissues during stress and aging makes them more susceptible to serious damage during periods of oxygen deficiency, as the iron atoms catalyze reactions such as lipid peroxidation."

– November 2017 – Ray Peats Newsletter

The role of heme oxygenase in progressive phenotypic improvement

"The true function of heme oxygenase is to support a progressive improvement in the organism's phenotype—rather than the aging, inflammation, fibrosis, and cancer that are currently the ultimate result of its activity. Heme oxygenase and the enzymes that produce NO, HCN, and H₂S may simply require guidance from an organism's response to an enriched environment."

– November 2017 – Ray Peats Newsletter

Thymus atrophy: causes and restorative factors

“Factors that cause thymus atrophy include cortisol and other glucocorticoid hormones, estrogen, prostaglandins, polyunsaturated fatty acids, lipid peroxidation, nitric oxide, endotoxin, hypoglycemia, and ionizing radiation. Progesterone and thyroid hormones support thymus restoration and offer protection by counteracting all of these atrophy-causing factors. Increasing dietary sugar intake may correct some of the metabolic changes associated with aging.”

– November 2016 – Ray Peats Newsletter

Estrogen, serotonin, and manipulation by pharmaceutical companies

"The manipulation of information about estrogen by pharmaceutical companies was even more extreme than their handling of serotonin. Activated under stress – along with serotonin – it is one of the most important activators of corticotropin-releasing hormone (CRH), which activates the pituitary gland and adrenal glands, promotes inflammation, and is a key factor in PPD (Glynn and Sandman, 2014; Hahn-Holbrook, 2016), as well as in other forms of depression, aging, and Alzheimer's disease."

– May 2019 – Ray Peats Newsletter

The effects of pregnancy on women's brain structure

“In women, MRI scans (Hoekzema et al., 2017) show that the brain’s gray matter shrinks considerably during pregnancy, similar to the changes seen in advanced age, and in some women these changes were still present two years later. However, another study found a very rapid recovery of brain structure in the second month after giving birth. In these healthy women, the brain recovery in this two-month period corresponded to a rejuvenation of five years (Luders et al., 2018).”

– May 2019 – Ray Peats Newsletter

Stress, metabolic energy and system integration

"In a healthy state, the stimulation of CRH production by histamine, serotonin, endorphins, IL-1, nitric oxide, and/or estrogen leads to the activation of complex and appropriate anti-stress responses. However, if stress is very intense or prolonged, or if nutrition has been inadequate, all activating signals—including CRH itself and the anti-stress glucocorticoids—can produce effects that are not integrated into the organism's functions as it copes with its problems. These effects generate symptoms and ultimately lead to degenerative processes and aging. This failure of integration is almost always the result of insufficient metabolic energy."

– May 2019 – Ray Peats Newsletter

Nutritional and age factors in chronic inflammation

"Poor nutrition, aging and other stressors weaken our anti-inflammatory defenses and lead to chronic systemic inflammation."

– March 2021 – Ray Peat's Newsletter

Link between chronic inflammation, aging and degeneration

"Prolonged exposure to environmental conditions far removed from the ideal conditions of a healthy pregnancy leads to a systemic inflammatory state, and this chronic inflammation leads to the degenerative processes of aging, associated with a failure of tissue renewal processes."

– March 2021 – Ray Peat's Newsletter

Stem cell depletion and senescence in aging tissues

"The loss of stem cells and the accumulation of senescent cells, which should have been replaced from the stem cell supply, are a general feature of aging, although tissues differ in the rate of stem cell loss according to their specific stresses."

– March 2021 – Ray Peat's Newsletter

Aging and PUFA accumulation increase prostaglandin production.

"As we age, more and more polyunsaturated fatty acids accumulate in our tissues, the production of prostaglandins increases, and the balance is less able to be fully restored."

– March 2017 – Ray Peat's Newsletter

Stress causes a decrease in testosterone and an increase in estrogen.

"In men, testosterone levels decrease due to stress and aging, and its conversion to estrogen is increased by stress and inflammation. Endotoxin specifically increases the conversion of testosterone to estrogen."

– March 2017 – Ray Peat's Newsletter

Age-related changes in the brain, exacerbated by estrogen

"With age, iron and polyunsaturated fatty acids accumulate in the brain. Estrogen slows the removal of dopamine, thus increasing its potential to react toxically with iron and highly unsaturated fatty acids, particularly arachidonic acid and DHA; it also tends to increase the production of prostaglandins and nitric oxide. Progesterone's anti-effects likely explain the lower incidence of Parkinson's disease in women compared to men."

– March 2017 – Ray Peat's Newsletter

Questioning the theory of antioxidant protection

"The enzyme that breaks down superoxide – superoxide dismutase (SOD) – is sold as a dietary supplement, in line with the cultural narrative that aging is caused by oxidative stress and that antioxidants protect. This view is increasingly being challenged as a reductive cellular state is recognized as a common factor in shock, stress, and degeneration."

– July 2019 – Ray Peats Newsletter

Information loss as a theory of aging and death

"The replacement of energy with information, the abstraction of the world, led to theories according to which the aging and death of organisms result from the inevitable entropic loss of information – the damage to DNA through somatic mutations caused by oxidative damage – as well as to a theory about the fate of the universe as entropic heat death."

– July 2017 – Ray Peats Newsletter

Aging, metabolic changes and the tendency towards cancer-like metabolism

"Aging itself involves a metabolic shift towards cancer metabolism, with a relative inability to reduce energy expenditure in the basal fasting state, as well as increased fatty acid oxidation and decreased glucose oxidation."

– July 2016 – Ray Peats Newsletter

Obstacles to understanding key biological concepts

"Some of the best-known ideas in biology – including genes, membranes and receptors – have hindered, and continue to hinder, our understanding of aging, cancer, stress, shock, epilepsy, regeneration, perception and thinking."

– January 2019 – Ray Peats Newsletter

Research into extending development and health

"The possibility of extending the developmental phase, delaying or eliminating aging, and restoring normal differentiation in cancerous tissue arose from the work of experimental embryologists who recognized the importance of studying the physicochemical properties of the living substance itself."

– January 2019 – Ray Peats Newsletter

The biological shift towards fat: Adaptive mechanisms of energy utilization

"The biological changes associated with the shift in fuel use from glucose to fatty acids and amino acids during stress, aging, and dementia have been termed deprivation syndrome ."

– January 2017 – Ray Peats Newsletter

Aging increases fatty acids in the brain.

"With age, the proportion of polyunsaturated fatty acids increases, and some of the arachidonic acid is incorporated into the brain. Particularly during the night, the highly unsaturated fatty acids intensify excitatory processes, including the formation of prostaglandins and other pro-inflammatory compounds."

– January 2017 – Ray Peats Newsletter

Factors that disrupt the balance of respiratory enzymes and PUFAs

"Vitamin E deficiency or an excess of PUFAs, due to ionizing radiation, oxygen deficiency, or aging. All these conditions involve impairment or reduced activity of the crucial respiratory enzyme cytochrome c oxidase."

– January 2016 – Ray Peats Newsletter

Identification of reductive stress through metabolic conditions

"With aging and during stress, the metabolism of animals shifts towards reduction, with a higher ratio of lactate to pyruvate, of NADH to NAD, of ascorbate to dehydroascorbate, etc. – a state of reductive stress."

– January 2016 – Ray Peats Newsletter

Age-related muscle loss, fat gain, and decreased insulin sensitivity

“Some of the obvious changes of aging, such as the loss of muscle mass (Martinez-Moreno et al., 2007), the increase in body fat (Bahadoran et al., 2015) and the decreased sensitivity to insulin (Ropelle et al., 2013), are caused by increased nitric oxide.”

– January 2016 – Ray Peats Newsletter

Restoring energy by inhibiting energy-limiting systems

"During aging and many stress-related conditions, it can be therapeutically beneficial to use substances that block our energy-limiting systems in order to allow the restoration of full energy production."

– January 2016 – Ray Peats Newsletter

Reversing skin aging with steroids and restoring hair growth

“People who studied the effects of steroids on aging skin found that the steroids that reversed the structural age-related changes in the skin (progesterone, testosterone, pregnenolone) sometimes restored hair growth.”

– Generative Energy: Restoring The Wholeness Of Life

Oxygen, iron, and their roles in aging and tissue degradation

"I think that oxygen waste is a key event in the aging process. Just as a cut potato needs oxygen to produce melanin, so do our tissues. Iron tends to accumulate in our tissues with age, and iron appears to be a factor in oxygen waste (especially in age pigment)."

– Generative Energy: Restoring The Wholeness Of Life

Analysis of the paradoxical properties of older blood

“Two clear differences have been found between old and young blood. The albumin in old blood is in a more oxidized state. (I believe it was the well-known gerontologist Verzar who first reported this.) Although the blood—at least in aging people—contains much less oxygen, something causes the albumin in older blood to be more oxidized. The other striking feature of older blood also seems paradoxical at first glance: the red blood cells are younger. That is to say, in an old person, the red blood cells are more fragile—possibly because they are damaged more quickly by oxidation—and are replaced sooner; on average, they are therefore many weeks younger than the cells of a healthy young person.”

None of these characteristics are truly paradoxical. Poor oxygenation is a stressor and causes glucose waste as well as compensatory mobilization of fat from stores. The relatively reducing environment in the cytoplasm leads to the mobilization of iron from stores—in its toxic reduced (ferro)form. Products of the peroxidative interaction of iron with unsaturated fatty acids are detectable in the blood (and other tissues) during stress, particularly pronounced in older animals.

– Generative Energy: Restoring The Wholeness Of Life

Dietary restriction and protein metabolism in old age

"One of the fundamental metabolic changes in old age is the slowing of the protein turnover rate in cells, and it appears that dietary restriction increases the protein turnover rate in aging animals. I think it is likely that both unsaturated fatty acids and the amino acid cysteine contribute to the age-related slowing of protein metabolism."

– Generative Energy: Restoring The Wholeness Of Life

Denckla's theory of a death hormone of the pituitary gland in the aging process

"W. Donner Denckla proposed that there is a death hormone in the pituitary gland that appears during puberty and initiates the aging process by suppressing oxygen utilization. He claimed that simply administering a thyroid hormone would not protect against it and that it was an independent hormone, even though it appeared to occur in tissue extracts in association with prolactin and growth hormone. Although I think there is still much to learn about pituitary hormones, I don't believe Denckla discovered anything other than puberty."

– Generative Energy: Restoring The Wholeness Of Life

Characteristic skeletal changes and stress hormones in old age

"The skeletal changes (shrinkage, curvature of the back, forward displacement of the lower jaw) that are so typical of old age in humans also occur in other animals with age and under the influence of stress hormones."

– Generative Energy: Restoring The Wholeness Of Life

Aging and the role of estrogen in the availability of reactive electrons

"In my experiments, I found that both aging and estrogen stimulation caused a strong increase in the availability of reactive electrons, which I measured by their reaction with a dye. These electrons originate from an interactive system that includes the proteins (cysteine) and glutathione, as well as various cofactor catalysts such as ascorbic acid and NADH."

– 2001 – February

Impairment of metabolism due to intensive training caused by the effects of lactic acid

"Intense training damages cells in a way that cumulatively impairs metabolism. There is clear evidence that glycolysis, the process by which glucose is converted into lactic acid, has toxic effects that suppress respiration and kill cells. Within five minutes of physical exertion, the activity of the enzymes that oxidize glucose decreases. Diabetes, Alzheimer's disease, and general aging involve increased lactic acid production as well as accumulated metabolic (mitochondrial) damage."

– 2000 – July

Exercise increases free fatty acids and lactate levels in the blood.

"Physical exertion—like aging, obesity, and diabetes—increases the concentrations of circulating free fatty acids and lactate. But ordinary, integrated physical activity activates the body's systems in an organized way and increases carbon dioxide and blood flow."

- 2000 - July

Mitochondrial metabolism as a central problem in aging and disease

"Mitochondrial metabolism is now considered the fundamental problem in aging and in several degenerative diseases."

– 2000 – July

DNA repair and cellular skin regeneration after sun exposure

"DNA repair is well understood in ordinary nuclear chromosomal genes. The other type of repair, in which non-mutated cells replace genetically damaged cells, has frequently been observed in facial skin: During intense sun exposure, mutated cells accumulate; but after a period without damaging radiation, the skin is once again composed of healthy, young cells. Just as we can see that the skin recovers from genetic damage previously considered permanent and cumulative—simply by avoiding the damaging factor—we are also beginning to view mitochondrial aging as both preventable and repairable."

– 2000 – July

Iron and calcium enrichment in old age and under stress

"Iron and calcium tend to accumulate with age or under stress, and both promote excitation-related damage; bicarbonate helps to keep iron in its inactive state and probably has a similar effect against a wide range of excitatory substances."

– 1999 – December – Ray Peat's Newsletter

Imperfection and adaptability of organisms under stress conditions

"Shock, inflammation, aging, and death have been proposed as survival-enhancing based on this totalitarian genetic view. Could it not be that organisms are simply not perfect and that some things just go systematically wrong? That is to say, an organism has a certain strength, resilience, or adaptability, but if it finds itself in excessively difficult conditions, processes can arise that never offered any survival advantage, as several otherwise useful defense mechanisms begin to hinder each other."

– 1998 – Ray Peats Newsletter – 4

Misconceptions about cellular mechanics lead to ineffective treatments.

"The inadequacy of the mental image of a cell with pumps and motors leads to shock being treated with things that produce shock, heart failure with things that produce heart failure, and aging with things that accelerate aging."

– 1998 – Ray Peats Newsletter – 4

Inhibition of connective tissue aging by carbon dioxide

"As we age, connective tissue hardens due to the chemical cross-linking of large molecules. If amino groups are well saturated with carbon dioxide, this type of reaction should be inhibited."

– 1998 – Ray Peats Newsletter – 3

The role of inflammation in aging and degenerative diseases

"What we call inflammation provides a good conceptual link between studies on excitotoxicity or cellular stress and newer approaches to treating aging and degenerative diseases, which are based on ideas of regeneration and development. Controlling inflammation becomes part of promoting regeneration."

– 1998 – Ray Peats Newsletter – 2

The decline in testosterone with age and hormonal changes

"Since the time of Brown-Séquard and Eugen Steinach, it has been generally accepted that declining testicular function is a typical feature of aging, and testosterone was probably the first hormone whose consistent decline with age was clearly established."

– 1998 – May – Ray Peats Newsletter

Decline in thyroid hormone T3 and aging effects

"The active thyroid hormone T3 decreases with age, and this inevitably reduces the production of pregnenolone and progesterone."

– 1998 – May – Ray Peats Newsletter

Increase in the estrogen/antiestrogen ratio in older men and women

"In aging women and men, when the breast and prostate atrophy, their estrogen/anti-estrogen ratio increases."

– 1998 – May – Ray Peats Newsletter

Decline in progesterone and pregnenolone in aging men

"Progesterone and pregnenolone levels also decrease in aging men."

– 1998 – May – Ray Peats Newsletter

The similarity between estrogen and aging in cellular calcium uptake

"Oxygen deficiency causes tissues to retain calcium (and iron), as does estrogen in many cases, since it—similar to the aging process—promotes cellular uptake of calcium. Because porphyrins strongly bind metals, it has been suggested that they may play a role in mediating metal deposition in stressed tissues."

– 1997 – Ray Peats Newsletter

Lactic acid as an indicator of respiratory deficiency

"In general, lactic acid in the blood can be considered a sign of faulty respiration, as the breakdown of glucose to lactic acid increases to compensate for a lack of oxidative energy production. Normal aging appears to involve a tendency towards excessive lactic acid production, and age pigment is known to activate this process."

– 1997 – Ray Peats Newsletter

Carrel's theory: Changes in body fluids during the aging process

"Carrel's work with tissue cultures led him to believe that changes in the organism's body fluids are an essential part of the aging process. Extracts from animal embryos were used medically to treat elderly people due to their confirmed effect on cell function."

– 1995 – September – Ray Peats Newsletter

Progesterone deficiency in old age and stress-related infertility

"It has now been proven that aging animals, at the point when they become infertile, have a progesterone deficiency but continue to produce estrogen. Even in young individuals, stress around the time of ovulation prevents implantation by impairing progesterone production. If progesterone becomes deficient after the embryo has implanted, a miscarriage occurs."

– 1995 – August/September – Ray Peats Newsletter

Aging of reproduction, hypothalamic regulation and hormonal support

"About 30 years ago, researchers began to understand that reproductive aging is not caused by a lack of eggs and that the aging uterus can support a pregnancy if it receives the right hormonal support. Interest turned to the brain cells in the hypothalamus that regulate the pituitary gland."

– 1995 – August/September – Ray Peats Newsletter

Stress, estrogen and the role of the brain in menopause and aging

“Stress, especially when amplified by estrogen, leads to damage, exhaustion, and aging. The uterus and ovaries participate in the stress response, but—as Zeilmaker and Wise have shown—the brain is more directly involved in menopause than the ovaries or uterus. Coordination proves crucial for complex processes such as ovulation, fertilization, and implantation. The destruction of the nerve cells that regulate the pituitary gland makes this coordination impossible.”

– 1995 – August/September – Ray Peats Newsletter

The role of gonadotropins in ovarian and brain function during the aging process

"Gonadotropins are involved in the development, maintenance, and function of the ovaries, and their effects depend on their timing, their balance with each other, and their interaction with the steroids produced by the ovaries in response to their stimulation. Their effects are also modified by many other factors—ovarian, nervous, pituitary, uterine, and immunological. In youth, this system functions in a coordinated manner, resulting in ovulation. In old age, however, the crucial changes appear to be a reduced capacity of the ovaries and brain to produce progesterone."

– 1995 – August/September – Ray Peats Newsletter

Current studies on reperfusion injury and factors of aging

"Reperfusion injury, any stress that causes oxygen depletion and an excessively reduced (electron-rich) cellular state, the importance of lipid peroxidation and iron in the aging process, and the role of iron in damaging steroid synthesis in steroidogenic tissues have recently been important areas of research."

– 1994 – June – Ray Peats Newsletter

The heart as an indicator of stress resistance and longevity

"The heart gives us some clues about our overall resilience to stress, aging, illness, and death. The heart and brain are the most stress-resistant organs, and while moderate stress and malnutrition can cause the skin and thymus gland to lose more than 90% of their substance, only the most prolonged and intense stresses can cause the heart and brain to lose more than a quarter of their substance."

– 1992 – June – Ray Peats Newsletter

The heart's stress resistance and its glucocorticoid resistance

"The many ways in which the heart is able to withstand and even benefit from stress can be generalized to develop ways of protecting other organs and the entire body from the chronic and cumulative stresses that lead to generalized atrophy, loss of function, and aging. During stress, the heart and other working organs become resistant to glucocorticoid hormones. When a person is given radioactive testosterone, it can be seen that it reaches its highest concentration in the heart. It is the antiglucocorticoid effect of testosterone that causes it to enlarge skeletal muscles during moderate exercise."

– 1992 – June – Ray Peats Newsletter

Heart protection against stress and general aging

"When reflecting on Meerson's achievements in protecting the heart from stress, it is important to remember that the heart is our most stress-resistant organ, and that the things that protect the heart from fatal stress also protect other organs from the everyday stresses that accumulate and cause the problems of general aging. The liver, lungs, pancreas, and other vital organs are exposed to the same kinds of damage as the heart—but under relatively mild and ordinary conditions."

– 1992 – June – Ray Peats Newsletter

Oxygen deficiency in old age and in cases of estrogen excess

"The regularity with which oxygen becomes deficient in old age, under stress and in excess of estrogen suggests that a basic coordination mechanism may be involved, in which there is a shift towards conditions that activate the expression of certain genes – possibly the hypoglycemia-stress-heat shock proteins or perhaps simply the proteins of cell division and growth."

– 1992 – June – Ray Peats Newsletter

Mechnikov's theories on aging, phagocytes, and bacterial toxins

"Although Mechnikov believed that phagocytes were responsible for the atrophy of aging, he also believed that bacterial toxins from the gut dominated the aging process."

– 1992 – August/September – Ray Peats Newsletter

Age-related decline in brain-stabilizing hormones

"With age, pregnenolone and its derivatives, progesterone and DHEA, decline sharply. The brain, the organ with the highest concentration of these stabilizing substances, has many systems to adapt to their decreasing levels, but the immune system is probably less able to compensate for these age-related changes."

– 1992 – August/September – Ray Peats Newsletter

Effects of thyroid hormones on sleep, cramps and anxiety

“Many people think of thyroid hormone as a kind of stimulant because it can cure the coma or lethargy of myxedema, but this is a highly misleading notion. In hypothyroidism, the brain-stimulating hormones adrenaline, estrogen, and cortisol are usually elevated, and the nerve-muscle relaxant magnesium is low. Normal, deep sleep is rare in a hypothyroid person. The correct dose of triiodothyronine (the active thyroid hormone) along with magnesium is a reliable treatment for insomnia, cramps, and anxiety—regardless of whether these symptoms are caused by exhaustion, aging, or alcohol withdrawal.”

– 1991 – June – Ray Peats Newsletter

Osmotic adaptation of salmon and accelerating aging hormones

“Another fish species, the salmon, which returns to freshwater to reproduce, shows the other extreme of adaptation to an osmotic problem. Having lived isotonic in the hypertonic ocean environment, maintaining its mineral content and osmolarity below that of seawater, it must suddenly adapt to extremely hypotonic freshwater. The secretion of prolactin and glucocorticoid hormones appears to facilitate this sudden adaptation, but these hormones also seem to cause an explosively rapid form of aging. I think their condition is similar to the Cushing-like symptoms commonly seen in middle-aged people.”

– 1991 – July – Ray Peats Newsletter

Link between stress hormones and aging through light research

"Having already spent several years investigating the effects of light on hormones and health, I began to realize that the existing knowledge about the involvement of stress and glucocorticoid hormones in the aging process perfectly matched my concept of winter sickness ."

– 1991 – January – Ray Peats Newsletter

Biochemical parallels between aging and estrogen dominance

"There are a large number of biochemical similarities between aging and the state of estrogen dominance – and no discernible biochemical differences between these states, apart from their history. For example, in both states the oxygen tension is relatively low, and as a result, unsaturated lipids are rapidly converted into age pigment or lipofuscin by lipid peroxidation."

– 1991 – January – Ray Peats Newsletter

Activated charcoal in the diet extends the lifespan of mice.

"The gerontologist VV Frolkis recently found that mice lived 43% longer than animals on a standard diet when activated charcoal was regularly added to their food. This is the clearest indication I have seen that intestinal toxins make a significant contribution to the aging process."

– 1991 – February/March – Ray Peat's Newsletter (1)

Intestinal toxins in the aging process: A late-acting, accelerating factor

"While Bogomoletz and Metchnikov viewed intestinal toxins as the factor driving the aging process, I see them more as a comparatively late-acting factor that accelerates a process arising from other causes. Once our detoxification mechanisms begin to fail, intestinal toxins pass through the gut with relative ease and rapidly destroy the remaining defense and detoxification systems."

– 1991 – February/March – Ray Peat's Newsletter (1)

Aging, hormonal changes and the balance of the gut flora

"The altered hormonal environment and the weakened digestion of an aging organism create a new balance between the animal and the intestinal flora, which sometimes allows the proliferation of more toxic flora."

– 1991 – February/March – Ray Peat's Newsletter (1)

Estrogen's toxic effects on the brain and aging

"Excessive blood clotting is just one of the problems that can be caused by an excess of estrogen, and I don't want to overemphasize it, as I consider its toxic effects on the brain and its acceleration of brain aging to be its worst effects."

– 1991 – April – Ray Peats Newsletter

Environmental influences that were ignored by the genetic reductionist school

"Although many types of experiments showed both prenatal and transgenerational influences of the environment on intelligence, body proportions and the rate of aging, the genetic reductionist school ignored these and defined itself as the only scientific school of biology."