Peat Archive

Ray Peat viewed cortisol as one of the key stress hormones whose chronic elevation drives aging and disease. While cortisol serves essential functions in acute stress (mobilizing fuel, suppressing inflammation), Peat emphasized that chronically elevated cortisol — driven by inadequate nutrition, thyroid deficiency, PUFA consumption, and other stressors — breaks down muscle and bone, promotes fat storage, suppresses immune function, and damages the brain.

Peat noted that cortisol and thyroid hormone have opposing actions: cortisol promotes gluconeogenesis (making glucose from protein), while thyroid supports efficient glucose oxidation. When thyroid function is low, the body relies more on cortisol to maintain blood sugar, creating a destructive cycle. He recommended addressing cortisol excess through frequent eating (sugar + protein), thyroid support, adequate sleep, and avoiding PUFAs.