Cortisol is a glucocorticoid hormone synthesized and secreted by the zona fasciculata of the adrenal cortex in response to adrenocorticotropic hormone (ACTH) from the anterior pituitary. It plays a central role in the hypothalamic-pituitary-adrenal (HPA) axis and is the primary stress-response hormone in humans. Cortisol levels exhibit a well-characterized diurnal rhythm, peaking in the early morning and declining to a nadir in the late evening. Cortisol regulates glucose metabolism by promoting gluconeogenesis and glycogenolysis, modulates immune and inflammatory responses, influences protein and lipid catabolism, and maintains vascular tone and fluid balance. Its release is governed by a negative feedback loop in which elevated cortisol suppresses CRH and ACTH secretion from the hypothalamus and pituitary, respectively. Chronic physiological or psychological stress, illness, and circadian disruption can significantly alter this regulatory axis.
Cortisol is a glucocorticoid hormone produced by the adrenal cortex in response to ACTH signaling from the pituitary. It regulates glucose metabolism, immune function, blood pressure, and the inflammatory response. Cortisol follows a strong diurnal rhythm, with peak levels occurring within 30-60 minutes of waking and a nadir around midnight.
Chronically elevated cortisol is associated with Cushing syndrome, characterized by central adiposity, muscle wasting, hyperglycemia, and immune suppression. Low morning cortisol may indicate adrenal insufficiency (Addison disease) or HPA axis suppression from exogenous glucocorticoid use. Single-timepoint cortisol has limitations due to pulsatile secretion and diurnal variation.
Exercise is a potent acute stimulus for cortisol release, with magnitude proportional to intensity and duration. Post-exercise cortisol elevation is a normal part of the stress-recovery cycle. However, persistently elevated cortisol — particularly resting morning cortisol — in the context of declining performance and mood changes is a recognized feature of overtraining syndrome (non-functional overreaching).
Turnaround Time
3 days (up to 12 days)
Method
Immunoassay (ECLIA)
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Cortisol is a glucocorticoid hormone synthesized and secreted by the zona fasciculata of the adrenal cortex in response to adrenocorticotropic hormone (ACTH) from the anterior pituitary. It plays a central role in the hypothalamic-pituitary-adrenal (HPA) axis and is the primary stress-response hormone in humans.
Cortisol is a glucocorticoid hormone produced by the adrenal cortex in response to ACTH signaling from the pituitary. It regulates glucose metabolism, immune function, blood pressure, and the inflammatory response.
Chronically elevated cortisol is associated with Cushing syndrome, characterized by central adiposity, muscle wasting, hyperglycemia, and immune suppression. Low morning cortisol may indicate adrenal insufficiency (Addison disease) or HPA axis suppression from exogenous glucocorticoid use.
The Cortisol test starts at $7.90 at Labcorp, Quest, or BioReference. No doctor's visit and no insurance needed; we do not bill insurance. Fitomics Insider members pay from $6.90.
Results for the Cortisol test are typically ready about 3 days after your draw, and up to 12 days for some samples. Your results land in your Insider portal.
No. When you order the Cortisol test from Fitomics Research Labs, a licensed physician in our 50-state network reviews and signs your requisition after checkout, and it lands in your portal and inbox. Then visit any Labcorp, Quest, or BioReference patient service center for your draw; results post to your Insider portal.
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