Ray Peat on Serotonin

Short answer: Ray Peat rejected the idea of serotonin as the happiness chemical. He described it as a signal of stress and energy shortage, tied to hibernation, inflammation and learned helplessness, and wrote about lowering it through diet, gut health and thyroid function.

What Ray Peat wrote about serotonin

He placed serotonin in the biology of withdrawal. It rises with stress and depression, and he connected that to its role in hibernation, an extreme form of harm avoidance. A diet high in polyunsaturated fat increases the tendency to hibernate, probably by raising the brain's uptake of tryptophan. Source: Serotonin: Effects in disease, aging and inflammation, Serotonin, depression, and aggression: The problem of brain energy

About 95% of the body's serotonin is in the intestine. Irritation of the gut causes endotoxin and serotonin to be absorbed, and that raises cortisol. Source: Serotonin: Effects in disease, aging and inflammation

He noted that the symptoms of too much serotonin overlap with the symptoms of low thyroid, and that hypothyroidism is a very common cause of high serotonin. Source: Serotonin, depression, and aggression: The problem of brain energy, Serotonin: Effects in disease, aging and inflammation

He criticized the tryptophan and SSRI story. Animal studies with anti-serotonin agents show more playfulness and faster learning, and an overdose of SSRIs or 5-HTP causes serotonin syndrome, which anti-serotonin drugs relieve. Source: Serotonin, depression, and aggression: The problem of brain energy

He connected serotonin to stress hormones: the excess tryptophan from muscle increases serotonin, and serotonin stimulates cortisol. Source: Gelatin, stress, longevity

He read Parkinson's disease this way too. The benefit of dopamine may come from its opposition to serotonin, and 5-HTP can make the symptoms worse. Source: Serotonin, depression, and aggression: The problem of brain energy

What he suggested in practice

• Avoid fermentable fibers and starches that resist digestion.
• Eat a raw carrot or bamboo shoots to lower endotoxin and serotonin.
• Use gelatin to balance the tryptophan in muscle meat. Gelatin contains no tryptophan.
• Correct low thyroid function. He wrote that when thyroid is supplemented until symptoms resolve, serotonin has probably normalized.
• Activated charcoal now and then.

Where he wrote about it

This topic comes up in 52 of the articles on his site. These are the most relevant ones:

• Tryptophan, serotonin, and aging · original on raypeat.com ↗
• Serotonin, depression, and aggression: The problem of brain energy · original on raypeat.com ↗
• Serotonin: Effects in disease, aging and inflammation · original on raypeat.com ↗
• Thyroid, insomnia, and the insanities: Commonalities in disease · original on raypeat.com ↗
• Intelligence and metabolism · original on raypeat.com ↗
• Multiple sclerosis, protein, fats, and progesterone · original on raypeat.com ↗
• Autonomic systems · original on raypeat.com ↗
• Gelatin, stress, longevity · original on raypeat.com ↗

My take

Serotonin is the gut's troublemaker. It drives intestinal inflammation, helps Gram-negative bacteria communicate and slows energy production in the brain. I lower it with salt, sugar, saturated fat, gelatin, calcium and magnesium, and a healthy gut.

Quick answers

What did Ray Peat say about serotonin?

He described serotonin as a mediator of stress, inflammation and energy conservation, not a happiness chemical. He linked high serotonin to low thyroid function, gut irritation, polyunsaturated fats and excess tryptophan.

How did Ray Peat suggest lowering serotonin?

By avoiding fermentable fiber, eating raw carrot, balancing muscle meat with gelatin, correcting low thyroid function, and keeping the intestine free of irritation.

What did Ray Peat say about SSRIs?

He argued that the theory behind them is wrong, that serotonin excess causes many of the symptoms they are meant to treat, and that anti-serotonin agents improve learning and playfulness in animals.