About Cortisol
Cortisol is your body's primary stress hormone, released by the adrenal glands in a circadian rhythm that peaks within 30–45 minutes of waking and gradually drops through the day. It regulates blood sugar, immune responses, blood pressure, energy metabolism, and the sleep-wake cycle — but chronic cortisol elevation from sustained stress, poor sleep, or adrenal dysfunction disrupts all these systems simultaneously. A morning serum cortisol gives a useful snapshot; a four-point salivary cortisol test provides a more complete picture of the full daily rhythm.