Cortisol (Morning) Test

Cortisol is the body's primary stress hormone, produced by the adrenal glands, and it plays essential roles in regulating metabolism, blood pressure, immune response, and the body's reaction to physical and emotional stress.

Cortisol naturally follows a distinct daily rhythm, rising to its peak shortly after waking in the morning and gradually declining throughout the day to its lowest point around midnight — a pattern that's fundamental to how this test is interpreted.

Because of this rhythm, a morning cortisol test captures the hormone at its expected peak, making abnormal results — either unusually high or unusually low at this specific time — particularly meaningful for identifying adrenal gland dysfunction.

Conditions affecting cortisol production can range from mild and manageable to serious and requiring urgent treatment, which is why this test is often just the first step in a broader adrenal function workup when results fall outside the expected range.