Cortisol Test: Understanding Your Stress Hormone Levels
Order Cortisol Levels Blood TestQuick Answer
Cortisol is the body's primary stress hormone, made by the adrenal glands. A cortisol test helps evaluate symptoms that may point to too much or too little of it.
Key Takeaways
- Cortisol is produced by the adrenal glands and follows a daily rhythm.
- Levels are typically highest in the early morning and lowest near midnight.
- A morning blood cortisol is a common first test for adrenal function.
- Persistently high cortisol can relate to Cushing's syndrome.
- Persistently low cortisol can relate to adrenal insufficiency.
- Because of the daily rhythm, collection time is critical to interpreting results.
What Is a Cortisol Test?
A cortisol test measures the level of cortisol, the body's main stress hormone. Cortisol is made by the adrenal glands, two small glands that sit on top of the kidneys. It helps regulate blood sugar, blood pressure, the immune response, and the body's response to stress.
Cortisol follows a daily pattern, called a diurnal rhythm. Levels peak in the early morning, shortly after waking, and drop to their lowest point around midnight. Because of this rhythm, the time of collection matters as much as the number itself.
Types of Cortisol Testing
| Method | What it captures |
|---|---|
| Morning blood cortisol | A snapshot of the peak level |
| AM/PM cortisol | Two samples showing the daily rhythm |
| Late-night salivary cortisol | A bedtime sample used to look for excess |
| 24-hour urine cortisol | Total output collected across a full day |
A clinician chooses the method based on the question being asked. Suspected cortisol deficiency is usually evaluated with a morning sample, while suspected excess may need a late-night or 24-hour collection.
Why a Cortisol Test Is Ordered
- Unexplained weight gain around the trunk and face
- Persistent fatigue, weakness, or dizziness
- High blood pressure that is hard to control
- Easy bruising, purple stretch marks, or muscle loss
- Low blood pressure, nausea, or salt craving
These symptoms overlap with many other conditions, so cortisol testing is usually part of a broader evaluation rather than a stand-alone diagnosis.
How to Read Your Results
A single cortisol value is hard to interpret without knowing when the sample was collected. A morning result far below the reference range can suggest adrenal insufficiency, while a bedtime result that stays high can suggest cortisol excess. Because stress, illness, shift work, pregnancy, and some medications shift cortisol, an abnormal result is often confirmed with a second test.
A related hormone, ACTH, is sometimes measured at the same time to help locate the cause, since it signals the adrenal glands from the pituitary. Always compare your values to the range and collection time on your own report.
How to Order / Where to Get Tested
You can order a cortisol test through a direct-access lab service in most states. Select a morning cortisol or an AM/PM panel online, pay at checkout, and visit a CLIA-certified lab or our partner lab for the blood draw. Some services also offer a salivary collection kit for a late-night sample. Results usually arrive within one to three business days.
If your state requires a physician order for direct-access testing, the service arranges one. Bring a photo ID to the appointment.
How Much Does It Cost
A single blood cortisol test commonly costs between $25 and $70 through direct-access services. An AM/PM cortisol panel that includes two draws costs more, and a 24-hour urine or salivary collection is priced separately. Insurance and Medicare usually cover cortisol testing when it is ordered to evaluate symptoms.
How to Prepare
Follow the collection time exactly, because the daily rhythm is the whole point of the test. Avoid strenuous exercise and heavy caffeine before a blood draw, and mention any steroid medications, including creams and inhalers, since they can lower natural cortisol. If you feel acutely ill, reschedule, because illness can temporarily raise levels.
Adrenal Insufficiency vs Cushing's Syndrome
Adrenal insufficiency means the body makes too little cortisol, which can cause fatigue, low blood pressure, and nausea. Cushing's syndrome means the body has too much cortisol, which can cause weight gain around the trunk, easy bruising, and high blood pressure. The two sit at opposite ends of the same measurement.
What Else Affects Cortisol
Shift work, poor sleep, emotional stress, pregnancy, and some medications can all change cortisol. Steroid medicines, including creams and inhalers, can lower natural production. Because so many factors are involved, an abnormal result is usually confirmed before it shapes treatment.
How Cortisol Is Regulated
Cortisol release is controlled by two other organs. The hypothalamus sends a signal to the pituitary, which releases ACTH, and ACTH tells the adrenal glands to make cortisol. When any part of this chain changes, cortisol moves with it. That is why a clinician may check ACTH together with cortisol to locate the cause.
Frequently Asked Questions
What is a normal cortisol level?
Normal ranges depend on the collection time and method. Morning blood levels are higher than evening levels, so your report lists the range for that sample type and time.
What does high cortisol mean?
Persistently high cortisol can suggest Cushing's syndrome, especially with weight gain, easy bruising, and high blood pressure. A single high value is usually confirmed with another test.
What does low cortisol mean?
Persistently low cortisol can suggest adrenal insufficiency, which may cause fatigue, low blood pressure, and nausea. It is often evaluated with a morning sample and ACTH.
Why does the time of the cortisol test matter?
Cortisol follows a daily rhythm, peaking in the morning and dropping near midnight. A value is only meaningful when the collection time is known.
Can I order a cortisol test directly?
Yes, direct-access services offer morning cortisol and AM/PM panels in most states. Some states require a physician order that the service provides.
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This guide is reviewed for sourcing accuracy against the references listed above. It is educational information, not medical advice. Always consult a qualified healthcare provider about your own results and care.
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