Cortisol is a hormone made by the adrenal glands. It helps the body respond to stress and plays a role in blood pressure, metabolism, and immune function. A cortisol test is a medical test used to investigate certain conditions; it is not a score of how stressed, tired, or healthy someone feels.
This guide explains the basics of testing and why results need a clinician’s interpretation. It does not diagnose a condition or replace medical advice. For an overview, read MedlinePlus: Cortisol Test.
What does a cortisol test measure?
A test measures cortisol in blood, urine, or saliva. A clinician may order one or more tests when a person’s history, symptoms, medicines, or other results suggest a problem involving cortisol production. Testing can help evaluate conditions such as Cushing syndrome or adrenal insufficiency. A test on its own may not identify the cause; follow-up tests can be needed.
Why does the time and type of test matter?
Cortisol levels change during the day, and different tests answer different questions. A clinician may request a blood draw at a particular time, a urine collection over a set period, saliva samples, or a supervised stimulation or suppression test. Follow the laboratory’s and clinician’s instructions. Do not change the timing, skip a medicine, or stop a steroid medication unless the prescriber tells you to do so.
How are results interpreted?
The reference range can differ by laboratory, sample type, collection time, and testing method. Medicines, pregnancy, illness, exercise, and stress can affect results. A value outside the printed range does not automatically confirm a diagnosis, and a single result may need to be considered alongside symptoms, medicines, examination findings, and other tests. Ask the ordering clinician to explain what the result means in your situation.
Common symptoms do not identify a cortisol problem
Tiredness, trouble sleeping, changes in appetite, or weight changes can have many causes. These symptoms cannot show that cortisol is “too high,” prove an adrenal problem, or tell someone to take a supplement. The Endocrine Society explains that “adrenal fatigue” is not a proven medical diagnosis, and that symptom lists or nonvalidated tests can delay finding the real cause. See its adrenal fatigue information.
What to ask at an appointment
- Why is this test being ordered, and which sample will be tested?
- What preparation or timing should I follow?
- Could any of my medicines or supplements affect the result?
- When and how will we review the result?
- If the result is unusual, what follow-up test or evaluation might be appropriate?
Be cautious with “cortisol detox” products
There is no routine or food plan that can diagnose or treat an adrenal or pituitary condition. Do not use a supplement or stop a prescribed medicine to change a test result without speaking with your healthcare professional. Some supplements can interact with medicines or have safety concerns. If you are considering a product, bring its label to a clinician or pharmacist.
When to seek medical care
If persistent symptoms concern you, make an appointment with a healthcare professional rather than trying to diagnose a hormone problem from a social-media checklist. Adrenal insufficiency is a real but uncommon medical condition that requires clinical assessment and testing. Severe illness or a suspected adrenal crisis needs urgent medical care. The National Institute of Diabetes and Digestive and Kidney Diseases describes how clinicians evaluate adrenal insufficiency.
Frequently asked questions
Can a home cortisol kit diagnose a condition?
Do not use a consumer test to diagnose a hormone disorder or start treatment on your own. Discuss testing options and interpretation with a qualified clinician.
Should I stop my medicine before the test?
Only if the clinician who ordered the test gives you that instruction. Some medicines can affect results, and stopping a prescribed medicine suddenly can be harmful.
Can daily habits replace medical testing?
Healthy routines may support general well-being, but they cannot confirm or rule out an endocrine condition. Ask a clinician about persistent or concerning symptoms.
