Ray Peat on Hans Selye

January 3, 2026

Selye's discovery of the phases of the adaptation system and stress immunization

"Hans Selye discovered that the adrenal glands are an essential part of our adaptation system. In the first stress phase, there is a shock response (with changes similar to those of estrogen dominance), associated with damage to various tissues. In the second phase, the adrenal glands protect the animal, and this protection lasts until exhaustion occurs. By subjecting rats to preliminary stress, Selye found that he could trigger an adaptation to other, subsequent stressors—a kind of immunization against stress."

Nutrition For Women

Hans Selye's view on stress and tissue activation

"According to Hans Selye, the activation or damage of tissue is the beginning of stress. The more cells involved, the greater the stress. An injury to a leg connected only by blood vessels triggers a stress response in the animal; the stress signal can therefore be transmitted via the blood, even though nerves are usually also involved. Adenine nucleotides have been suggested as a cause of shock (because they have a vasodilatory effect, like many other stress products, including phosphate), but other possibilities include histamine, various polyamines, and low blood sugar."

Nutrition For Women

Selye's stress phases and their effects on tissue

"Selye divides stress into three phases: alarm, resistance (or adaptation), and exhaustion. Three tissues usually show effects first: thymolymphatic tissue shrinks, gastrointestinal tissue becomes inflamed and bleeds, and the adrenal cortex enlarges."

Nutrition For Women

Selye's classification of steroids: anti-inflammatory and pro-inflammatory.

"Selye classifies steroids into anti-inflammatory and pro-inflammatory. Inflammation is a relatively non-specific and hopefully local reaction that serves to isolate the problem if it is a toxin or an infection. Cortisol is a typical anti-inflammatory hormone;"

Nutrition For Women

Vitamin E alleviates iron-induced stress arthritis in animals

"Hans Selye sometimes used an injected metal, such as iron salts, to experimentally sensitize animals to stress and thus facilitate the development of arthritis. He found that vitamin E could counteract this effect of iron."

Nutrition For Women

Stress affects steroids and causes degenerative diseases in the gastrointestinal system.

"Stress consumes steroids and produces the many degenerative diseases described by Hans Selye. The gastrointestinal system becomes inflamed or develops ulcers, and fibrous tissue can proliferate. The adrenal glands enlarge, and lymphoid tissue shrinks in the initial stress phase (and may enlarge later)."

Nutrition For Women

The role of vitamin C in the prevention of heavy metal toxicity

"Hans Selye has shown that vitamin C can prevent heavy metal toxicity (e.g., from mercury); it reduces the metal to a less toxic form and also helps to dissolve and eliminate it."

Nutrition For Women

Overlooked effects of stress on the gut

"While the effects of stress on the gut have been known since Hans Selye described the general adaptation syndrome (with intestinal bleeding being an early sign of stress), this has not been taken into account in any of the major studies on severe brain trauma or strokes."

March 2016 - Ray Peat's Newsletter

Selye's observations on cellular aging and adaptation

"Hans Selye observed the reaction to a small glass tube inserted under the skin of a rat. He noticed that the tube was soon enclosed by a capsule of fibrous tissue and that the cells gradually grew in a strand along the canal of the tube from the ends. These cells were isolated from the fluids that normally surround cells, and Selye found that after a short time they took on the appearance of cells from a very old animal, while the cells of the surrounding capsule remained normal. Selye drained the fluid at intervals so that it was replaced by fresh fluid and found that at the end of the rat's lifespan, the cells of this strand showed no signs of aging whatsoever."

September 1995 - Ray Peat's Newsletter

Estrogen's systemic effects and stress adaptation

"Around 1940, Hans Selye observed that the systemic effect of estrogen mimics the shock phase of the stress response. In shock, insufficient blood flow and thus insufficient oxygen supply to the tissues is the main problem, and Selye considered adrenal steroids crucial to solving this problem and enabling adaptation to stress."

July 1991 - Ray Peat's Newsletter

Estrogen treatment and the shock phase of the stress response

"Hans Selye pointed out that estrogen treatment mimics the first, shock phase of the stress response. An excess of estrogen (or any other stressor) causes the pituitary gland to release prolactin and ACTH, and both hormones act on the ovaries in such a way that progesterone production is stopped,"

October 1990 - Ray Peat's Newsletter

The protective effects of pregnenolone and progesterone in autoimmune diseases

"Besides their direct protective effect on the thymus, pregnenolone and progesterone have a vitamin A-sparing effect, and they also have that very general protective effect that Selye described as catatoxic. Both hormones have been used effectively to treat various autoimmune diseases. They tend to increase body temperature and metabolic rate, but are anti-catabolic."

November 1989 - Ray Peat's Newsletter

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