Detailed definition
Cortisol is a C21 steroid hormone produced by the zona fasciculata of the adrenal cortex under stimulation from adrenocorticotropic hormone (ACTH) released by the anterior pituitary. ACTH itself is regulated by hypothalamic corticotropin-releasing hormone (CRH), forming the hypothalamic-pituitary-adrenal (HPA) axis. Cortisol follows a circadian rhythm with peak levels in the early morning and trough in late evening. It mobilizes glucose from glycogen and gluconeogenesis, suppresses inflammation, modulates immune cells, and influences mood, cognition, and cardiovascular tone. Cortisol's relationship to menopause is bidirectional. Disrupted sleep from night sweats elevates evening cortisol and flattens the diurnal curve, which feeds insomnia and metabolic dysregulation. Estradiol withdrawal also appears to alter HPA axis reactivity, and some studies show flatter or higher cortisol curves in postmenopausal women. Salivary cortisol panels are sometimes ordered in a menopause workup, though the clinical value of routine adrenal testing in symptomatic perimenopause is limited.
Why it matters in menopause
Many women presenting with menopausal exhaustion, weight gain, and sleep disruption are told they have "adrenal fatigue" — a diagnosis the Endocrine Society does not recognize. Real adrenal insufficiency is a serious medical condition with specific lab findings; chronically elevated stress cortisol from disrupted menopause sleep is a different problem and is best addressed by treating the sleep disruption (often with bedtime progesterone) rather than by salivary cortisol panels and adrenal supplements.