Cortisol – The body's primary stress hormone

What is Cortisol?

Cortisol is produced in the adrenal cortex and is controlled by the pituitary gland and hypothalamus in the brain. The hormone affects metabolism, blood sugar, blood pressure and the immune system, and normally follows a clear daily rhythm with a peak in the morning and its lowest levels at night.

Why is Cortisol measured in a health check?

Cortisol is measured mainly to investigate suspected over- or underproduction in the adrenal glands, for example in cases of unexplained weight loss, low blood pressure, extreme fatigue, or symptoms suggestive of Cushing's syndrome. In a health check the test can give a snapshot of the stress hormone, but it never replaces a broader assessment of long-term exhaustion.

High and low values

High value: High values can be seen with significant physical or psychological stress, certain medicines such as corticosteroids, and conditions involving overproduction in the adrenal glands. A single high value always needs to be considered in context, including the time of day and the circumstances of the blood draw.

Low value: Low values can suggest adrenal insufficiency, a condition in which the adrenal glands do not produce enough hormone. This requires medical assessment and should never be self-diagnosed from a single blood test.

Reference ranges differ between laboratories, sexes and ages and are stated in your result. The information here does not replace medical assessment.

How is a cortisol test taken in a health check?

A cortisol test in a health check is a standard venous blood test taken from the crook of the arm, just like the other markers in the sample. What sets cortisol apart from many other tests is how sensitive the result is to the time of day. The body's cortisol level follows a daily rhythm governed by the internal clock: it rises before you wake, peaks shortly after waking, and then gradually falls through the day to its lowest point at night. A cortisol blood test taken at midday or in the evening therefore says something different from one taken in the morning, and the two cannot be compared directly.

In practice, this means most health checks recommend that the cortisol test be taken in the morning, often within a couple of hours of waking, so the result can be interpreted against established patterns. If you have irregular sleeping hours, work nights, or have recently changed time zones, it's worth mentioning at the blood draw, since it affects when your own cortisol peak actually occurs. Even acute stress immediately before the blood test, such as discomfort about the needle, can temporarily raise the value without reflecting long-term stress levels.

What does the daily rhythm mean for interpretation?

The daily rhythm is the single most important factor to understand when reading a cortisol result. Because the level can normally differ several times over between morning and evening in the same healthy person, a cortisol value is almost meaningless without knowing what time it was taken. For this reason, no numerical ranges are given here — reference values are always tied to a specific time of day and to the individual laboratory's method, and they appear on the test report you receive.

In some cases healthcare providers want to see how cortisol changes over the day, for example by comparing a morning sample with one taken later, or through more advanced investigation with stimulation or suppression tests. A single health-check blood test gives a snapshot, while a full assessment of adrenal function often requires several measurement points and a doctor's interpretation of the whole picture, not just the number itself.

Can cortisol show stress and burnout?

Many people who order a health check do so precisely because they feel exhausted, stressed, or heading towards burnout, and cortisol is often one of the tests requested in the belief that it will give a clear answer. The reality is more complicated. Cortisol does respond to stress, but the response is individual, temporary, and influenced by countless factors such as sleep, meals, exercise, and mood at the exact moment the sample was taken. There is no established pattern where a particular cortisol value conclusively proves either a high stress load or burnout.

This is a key reason why a single blood test can never diagnose exhaustion disorder. The diagnosis instead relies on an overall clinical assessment: the symptom pattern over time, impaired everyday functioning, sleep quality, and ruling out other medical causes of fatigue such as thyroid disorders, anaemia, or vitamin deficiency. A cortisol test can be part of a broader investigation, but it should never be treated as a verdict in itself, whether the value is high, low, or within the expected range.

When should you contact a doctor about cortisol?

You should seek medical care if you have symptoms such as severe and persistent fatigue, unexplained weight loss, low blood pressure, darkening of the skin, or dizziness on standing, since these can point to adrenal insufficiency — a condition that requires medical investigation and treatment and cannot be established on your own from a health-check result. The same applies to symptoms that may suggest cortisol overproduction, such as rapid weight gain in the face and trunk, muscle weakness, or easy bruising.

For more diffuse complaints such as long-term stress, sleep problems, or a feeling of exhaustion, the next step is usually a conversation with a doctor rather than a single blood test. The doctor can then judge whether cortisol, thyroid tests, a full blood count, or other markers need to be added, and put the symptoms into a context that a single test result can never provide. A health check with a blood test can be a good starting point for ruling out other causes, but it does not replace a clinical assessment when symptoms are pronounced or persistent.

Frequently asked questions about Cortisol

Health checks that include Cortisol

Cortisol is included in 6 of Labkollen's health checks. Analysis name in the result: Kortisol, S-Kortisol.

• Kvinna +

  44 markers

  Labkollens mest omfattande kontroll för kvinnor – inklusive järnstatus, sköldkörtel och hormoner.

  2 095 krMed prenumeration (årlig hälsokontroll): 1 676 kr

  See the test

• Seniorkollen

  32 markers

  Anpassad kontroll för dig över 65 med fokus på hjärta, njurar, sköldkörtel och näringsstatus.

  1 299 krMed prenumeration (årlig hälsokontroll): 1 039 kr

  See the test

• Lagsport

  16 markers

  För lagidrottare – energi, järn, återhämtning och stresshormon.

  1 499 krMed prenumeration (årlig hälsokontroll): 1 199 kr

  See the test

• Kampsport

  15 markers

  För kampsportare – återhämtning, hormoner, inflammation och järn.

  1 499 krMed prenumeration (årlig hälsokontroll): 1 199 kr

  See the test

• Hormon/balans

  8 markers

  Bred hormonprofil vid humörsvängningar, oregelbunden cykel eller låg energi.

  899 krMed prenumeration (årlig hälsokontroll): 719 kr

  See the test

• Stresskollen

  5 markers

  Kortisol och basmarkörer vid långvarig stress, sömnbrist eller utmattningskänsla.

  499 krMed prenumeration (årlig hälsokontroll): 399 kr

  See the test

Unsure which test you need? Start the test guide