Ray Peat on Cortisol and Stress

Short answer: Ray Peat described cortisol as the hormone that keeps you alive by taking you apart. It rises when sugar and energy run short, breaks down muscle and thymus, and shrinks the brain. He lowered it with food, light and the protective hormones, not with willpower.

What Ray Peat wrote about cortisol

Cortisol protects cells in an emergency by blocking over-stimulation and supplying material for energy. But it can kill the cells that depend on glucose, such as nerve cells and thymus cells, leading to immune deficiency and brain damage. Source: Cataracts: water, energy, light, and aging

He pointed to Cushing's disease: too much cortisol shrinks the brain, and when the cortisol is normalized the brain size is restored. Source: The dark side of stress (learned helplessness)

Sugar is the first answer. He lists sugar as reducing cortisol, adrenaline and free fatty acids, and wrote that sugar together with fat and minerals, as in milk, is needed to lower cortisol and keep the thyroid working. Source: Lactate vs. CO2 in wounds, sickness, and aging; the other approach to cancer, Multiple sclerosis, protein, fats, and progesterone

Wild monkeys have low cortisol on a fruit diet and higher cortisol when they eat less sugar. Source: Sugar issues

Eating only muscle meat mimics stress. Its tryptophan raises serotonin, and serotonin stimulates more cortisol. Source: Gelatin, stress, longevity

Gut irritation raises it through endotoxin and serotonin. Source: Serotonin: Effects in disease, aging and inflammation

Darkness raises it. So does the long night without food, until breakfast lets it fall. Source: Stem cells, cell culture, and culture: Issues in regeneration, TSH, temperature, pulse rate, and other indicators in hypothyroidism

Progesterone restrains it, by damping the ACTH stress response and limiting cortisol's harmful actions. Cortisol in turn drives estrogen production in fat. Source: Preventing and treating cancer with progesterone, Breast Cancer

A deficient thyroid leaves cortisol in excess relative to pregnenolone and progesterone. That ratio is how he defined the energy-deficient state. Source: The transparency of life: Cataracts as a model of age-related disease

What he suggested in practice

• Sugar with minerals: milk and fruit.
• Breakfast, and something salty and sweet before bed.
• Gelatin with meat.
• Light, especially in winter.
• A daily raw carrot.
• Vitamin B1 and niacinamide, which he lists with sugar among the things that lower stress hormones.

Where he wrote about it

This topic comes up in 66 of the articles on his site. These are the most relevant ones:

• Estrogen — Age Stress Hormone · original on raypeat.com ↗
• Glycemia, starch, and sugar in context · original on raypeat.com ↗
• Immunodeficiency, dioxins, stress, and the hormones · original on raypeat.com ↗
• Multiple sclerosis, protein, fats, and progesterone · original on raypeat.com ↗
• Stem cells, cell culture, and culture: Issues in regeneration · original on raypeat.com ↗
• Hot flashes, energy, and aging · original on raypeat.com ↗
• TSH, temperature, pulse rate, and other indicators in hypothyroidism · original on raypeat.com ↗
• The dark side of stress (learned helplessness) · original on raypeat.com ↗

My take

The gut, muscle and brain carry the most cortisol receptors. More cortisol means less muscle, lower brain volume, slower gut motility and a weaker gut barrier. I keep it down with carbs, salt, sleep and sunlight.

Quick answers

What did Ray Peat say about cortisol?

That it is an emergency hormone which, when chronically high, breaks down muscle, thymus and brain tissue, and that it rises whenever sugar and cellular energy are short.

How did Ray Peat suggest lowering cortisol?

With enough sugar together with minerals, as in milk and fruit, with breakfast and food at bedtime, gelatin, salt, light, good thyroid function and the protective hormones progesterone and pregnenolone.