Cortisol, PM Unit Converter

Cortisol is your body's primary stress hormone, a glucocorticoid produced by the adrenal glands. It plays a central role in metabolism, immune function, and the stress response.

Cortisol follows a strong diurnal rhythm: levels peak in the early morning and decline throughout the day, reaching their lowest point around midnight. A PM cortisol test measures your levels in the late afternoon or early evening (typically between 4 and 8 PM), when they should be significantly lower than in the morning.

Measuring cortisol in the afternoon helps assess whether your body is following its normal daily pattern. Persistently elevated PM cortisol may suggest that the expected daily decline is not occurring, which can be an early sign of conditions like Cushing's syndrome.

Cortisol is produced in the zona fasciculata of the adrenal cortex, located on top of each kidney. Its release is regulated by the hypothalamic-pituitary-adrenal (HPA) axis, where the hypothalamus signals the pituitary gland to release ACTH, which in turn stimulates cortisol production.