Hormones
Cortisol
LOINC 2143-6 · mcg/dL
Ranges
Reference range: 6.2–19.4 mcg/dL
What it is
Cortisol is a hormone from the adrenal glands that helps manage stress, blood sugar, blood pressure and metabolism. It follows a daily rhythm.
Why it matters
It helps assess adrenal and pituitary function and is used to investigate conditions of too much or too little cortisol.
What high values can mean
A higher value can relate to stress, certain medications or conditions that overproduce cortisol.
What low values can mean
A lower value can indicate the adrenal glands are underactive, which needs medical attention.
How to improve it
Cortisol reflects the stress-response system; managing stress and sleep supports a healthy rhythm, but abnormal results need evaluation.
Food & lifestyle
Good sleep, stress management and regular routines support a healthy cortisol rhythm.
Preparing for the test
Timing matters: cortisol is usually highest in the morning, so samples are often drawn around 8 a.m. — follow your lab.
When to talk to a doctor
Discuss a clearly high or low cortisol with a doctor, who interprets it with the time of day.
Related markers
Sources
- MedlinePlus (NIH)
- Testing.com (AACC)
Content reviewed on June 26, 2026
Medical disclaimer
This content is for educational purposes only. It is not medical advice and does not diagnose, treat, or prevent any condition. Reference ranges vary between laboratories — always use the range printed on your report and discuss your results with a healthcare professional.
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