Cortisol, AM Unit Converter

Cortisol is the body's primary stress hormone. It plays a central role in metabolism, immune function, blood pressure regulation, and the stress response.

Cortisol follows a strong circadian rhythm, peaking in the early morning and gradually declining throughout the day to reach its lowest levels around midnight. An AM cortisol test measures levels during this natural morning peak, typically between 7 and 9 AM.

About 75-80% of cortisol in the blood is bound to cortisol-binding globulin (CBG), roughly 15% is bound to albumin, and only about 5-10% circulates as free, biologically active hormone. Standard blood tests measure total cortisol (both bound and free).

Cortisol is produced by the adrenal cortex (the outer layer of the adrenal glands, which sit on top of each kidney). Its release is controlled by the hypothalamic-pituitary-adrenal (HPA) axis: the hypothalamus releases CRH, which signals the pituitary to release ACTH, which then stimulates the adrenal glands to produce cortisol.