Hormone Panel Updated Apr 17, 2026

Cortisol

Cortisol is a steroid hormone made by the adrenal glands and measured in blood tests to show how much Cortisol is circulating at the time of collection. On a lab report, it helps describe hormone balance, time-of-day variation, and how the body is responding to stress, activity, and other factors. Because Cortisol changes across the day, the Cortisol test result is usually interpreted with the collection time and the lab’s Cortisol normal range.

What Is Cortisol?

Cortisol is a steroid hormone measured in blood as part of a Cortisol test. It is made by the adrenal glands and circulates in the bloodstream in small amounts. A Cortisol on a lab report reflects the amount present at the time of collection, which can vary across the day. It is one of the hormone values used to describe how the body is regulating stress-related chemistry and metabolism.

Why Is Cortisol Tested?

Cortisol is commonly measured in a Hormones panel and may also appear in broader hormone-focused testing. A Cortisol test helps describe the current level of circulating cortisol at the moment of collection. In routine lab review, the Cortisol on a blood test adds context about time-of-day patterns and overall hormone balance. The result is often interpreted with the lab’s reference interval and collection time.

Already have your Cortisol results?

Upload your blood test to BloodSight and see what each result means in context.

Get Started

Cortisol Normal Range

Group Range Unit
Adult Male 5–23 mcg/dL
Adult Female 5–23 mcg/dL

Reference ranges may vary by laboratory and individual factors.

What Does High Cortisol Mean?

A high Cortisol test result means the measured cortisol level is above the lab’s Cortisol reference range for that sample time. Many labs consider morning cortisol values above about 19 to 23 mcg/dL, or 525 to 635 nmol/L, as high, depending on the method and timing. High Cortisol generally reflects a stronger concentration of circulating hormone at the time of draw. On a lab report, this can happen when the blood sample is concentrated or when the body is producing more cortisol than usual.

Associated factors

Stress or recent physical strain — short-term hormone release can raise measured Cortisol.
Time of day — Cortisol is naturally higher in the morning, so a morning Cortisol test can look high compared with later samples.
Dehydration — reduced plasma volume can concentrate the measured Cortisol.
Pregnancy — binding proteins rise and can increase total Cortisol on a blood test.
Recent intense exercise — activity can temporarily increase circulating Cortisol.
Smoking — nicotine exposure can shift hormone levels and raise Cortisol.
Caffeine intake — stimulant intake may increase short-term Cortisol levels.
Certain hormone medicines — some medicines can increase measured Cortisol or affect how it is reported.
Obesity-related metabolic variation — body composition can influence baseline Cortisol patterns.
Acute illness or recovery from injury — temporary physiologic stress can raise Cortisol.

What Does Low Cortisol Mean?

A low Cortisol test result means the measured cortisol level is below the lab’s Cortisol normal range for that sample time. Many labs consider morning cortisol values below about 5 mcg/dL, or 138 nmol/L, as low, depending on the method and timing. Low Cortisol generally reflects a smaller concentration of circulating hormone at the time of draw. On a lab report, it can also reflect shifts in binding proteins or timing of collection rather than a long-term pattern.

Associated factors

Late-day collection — Cortisol falls through the day, so afternoon or evening samples can read low.
Overhydration — extra fluid can dilute blood values and lower measured Cortisol.
Recent long-term steroid medicine use — some medicines can suppress the body’s own Cortisol output.
Reduced calorie intake — lower energy intake can decrease hormone production.
Major body composition changes — changes in body mass can shift baseline Cortisol levels.
Heavy alcohol intake — alcohol exposure can affect hormone regulation and lower Cortisol in some settings.
Certain hormone medicines — some treatments can change measured Cortisol or its binding proteins.
Unusual pituitary signaling — altered signaling can reduce adrenal Cortisol output.
Chronic sleep disruption — altered daily rhythm can flatten the normal Cortisol pattern.
Normal morning-to-evening rhythm — later samples can show low Cortisol even when the daily pattern is normal.

How Cortisol Relates to Other Values

Cortisol is often reviewed with other hormone values from the same panel and with timing information from the draw. In broader lab work, it may be compared with glucose, sodium, potassium, and albumin because these values help describe fluid balance and overall blood chemistry. If Cortisol is checked alongside hematocrit (Hct), red blood cell count (RBC), and mean corpuscular volume (MCV), the result can help separate hormone-related variation from changes in red cell concentration. A Cortisol test result is read with the collection time because the Cortisol normal range depends on when the sample was taken.

What Factors Affect Cortisol Levels?

Age can affect Cortisol patterns, especially the daily rise and fall that appears in blood tests. Sex hormones can shift Cortisol binding and change the reported value. Hydration, recent exercise, smoking, alcohol intake, and caffeine can all influence a Cortisol test result. Time of day is one of the biggest factors, so the Cortisol normal range is usually tied to the collection time. Different lab methods can also produce slightly different reference ranges for the same Cortisol sample.

How It Is Tested

Cortisol is measured from a blood sample drawn from a vein, and the lab reports the concentration of cortisol in the serum or plasma. Results are usually reported in mcg/dL or nmol/L, depending on the lab method. On a lab report, the Cortisol on a blood test is interpreted against the lab’s time-specific reference range.

How to Prepare

For a Cortisol test, no fasting is usually required unless another test on the same panel has its own instructions. Collection time matters because Cortisol changes during the day.

Frequently Asked Questions

What is a normal Cortisol level?
A normal Cortisol level depends on the time of collection and the lab method. Many morning reference intervals are around 5 to 23 mcg/dL, but the Cortisol normal range can differ by lab. The Cortisol test result should always be read with the listed reference range on the report.
What does Cortisol stand for?
Cortisol does not stand for a longer acronym; Cortisol is the hormone name itself. In a blood test, Cortisol refers to the circulating steroid hormone measured in the sample. On a lab report, it is usually listed simply as Cortisol.
What does a high Cortisol mean on a lab report?
A high Cortisol means the measured value is above the lab’s Cortisol reference range for that collection time. This can reflect a concentrated sample, a morning draw, or a temporary increase in hormone output. A high Cortisol test result is interpreted with timing and other lab values, not by the number alone.
What does a low Cortisol mean on a lab report?
A low Cortisol means the measured value is below the lab’s Cortisol normal range for that collection time. Late-day collection, dilution from extra fluid, or reduced hormone output can all be linked with low Cortisol. The Cortisol test result is most useful when compared with the reference range printed on the report.
Can hydration affect Cortisol?
Yes. Hydration can affect Cortisol because extra fluid may dilute the sample and lower the measured concentration, while less fluid can make it look higher. This is one reason a Cortisol on a blood test is read together with the collection context.
What is the difference between Cortisol and glucose?
Cortisol is a hormone value, while glucose is a sugar measurement. Cortisol on a lab report reflects hormone level at the time of draw, and glucose reflects the amount of circulating sugar. They are often reviewed together because both can shift with time of day, activity, and other factors.
What unit is Cortisol measured in?
Cortisol is commonly measured in mcg/dL or nmol/L. Some laboratories use one unit format, while others report the same Cortisol test result in the other unit. The report should list the unit beside the value and the Cortisol normal range.
How much can Cortisol change between tests?
Cortisol can change a lot between tests because it follows a daily rhythm. A morning sample can be much higher than an afternoon sample, even when the same person is tested on the same day. This is why the Cortisol test is interpreted with the time of collection.
Is Cortisol different for men and women?
Cortisol can be reported with the same general reference range for adult men and women, but hormone states can shift the measured value. Pregnancy, hormone medicines, and differences in binding proteins can change the Cortisol test result. The lab report should be read using the listed reference interval for that specific method.
Why is Cortisol tested in a Hormones panel?
Cortisol is included in a Hormones panel to show the amount of circulating cortisol at the time of collection. It adds context about daily rhythm, hormone balance, and how other markers may relate to the result. On a lab report, the Cortisol test is most useful when paired with the panel’s reference range and draw time.
What does Cortisol on a blood test mean?
Cortisol on a blood test means the lab measured the amount of cortisol in the blood sample. The result reflects the level at the moment of collection and is affected by time of day. The Cortisol normal range on the report helps show whether the value is high Cortisol, low Cortisol, or within range.

Disclaimer

This content is for informational and educational purposes only. It is not intended as medical advice, diagnosis, or treatment recommendation. Reference ranges may vary by laboratory. Always discuss your results with a qualified healthcare professional.

Related Tests

Testosterone

Testosterone is a hormone measured in blood that helps describe hormone balance and related body functions. On a lab report, Testosterone on a blood test is often reviewed for pattern changes over time and alongside other markers. The Testosterone normal range depends on sex, age, lab method, and the units used.

→
Free Testosterone

Free Testosterone is the unbound portion of testosterone circulating in blood. It is the fraction not attached to carrier proteins, so it is the part most available for biologic activity. On a blood test, Free Testosterone helps show how much testosterone is circulating in a usable form and is often read alongside total testosterone and sex hormone–binding globulin (SHBG).

→
Estradiol E2

Estradiol (E2) is the main form of estrogen measured in blood, and an Estradiol test reports how much E2 is circulating at the time of collection. E2 on a lab report is commonly used in hormone panels to track normal variation across sex, age, and treatment patterns.

→
Progesterone

Progesterone is a steroid hormone measured in blood to show how much of this hormone is circulating at the time of testing. On a lab report, Progesterone helps describe hormone patterns across different sex and reproductive states, and results are often read as part of a broader Hormones panel. The Progesterone test result is usually reported in ng/mL or nmol/L, and the Progesterone reference range depends on age and sex.

→
DHEA-Sulfate DHEA-S

DHEA-Sulfate (DHEA-S) is a steroid hormone made mainly by the adrenal glands and measured in blood. On a DHEA-S lab report, the value helps show how much sulfate-bound androgen precursor is circulating. Results are often read with age, sex, and other hormone markers because normal DHEA-S levels vary widely.

→
Parathyroid Hormone PTH

Parathyroid Hormone (PTH) is a hormone measured in blood to show how much parathyroid signal is circulating at the time of the test. PTH on a lab report helps describe how the body is regulating calcium and related minerals. The result is often interpreted with other markers and the Parathyroid Hormone reference range for the same lab method.

→