Cortisol
Cortisol is the body's main stress hormone, produced by the adrenal glands to regulate metabolism, energy, and the response to threat while modulating immune function and inflammation.
Cortisol is a steroid hormone produced by the adrenal glands that regulates metabolism, blood sugar, and the body's response to stress. As the primary glucocorticoid, it helps mobilize energy during threat detection, suppresses non-essential functions like digestion, and modulates immune activity. Its levels naturally rise in the morning and fall at night, following a circadian rhythm essential for health.
What this means in real life
When a student faces an exam, their body releases cortisol to sharpen focus and boost energy. After the test, levels drop. But if someone worries constantly about exams for months, cortisol stays high, leaving them exhausted and prone to illness.
What it isn’t
Cortisol is not adrenaline—adrenaline is the quick 'fight or flight' rush you feel instantly, while cortisol is the slower hormone that sustains your stress response over hours or days.
Commonly misused online
Social media often blames 'high cortisol' for every modern ailment (weight gain, aging, mood) without acknowledging that cortisol is necessary and only harmful when chronically dysregulated, not simply present.