High cortisol: symptoms, tests & diagnosis online

High cortisol can signal serious health issues such as Cushing’s syndrome, long-term steroid exposure, or chronic stress. Diagnosing it correctly is challenging because cortisol is pulsatile, follows a circadian rhythm, and is mostly protein-bound. This comprehensive guide explains what “high cortisol” actually means, which symptoms warrant testing, and how key tests—late-night salivary cortisol, 24-hour urinary free cortisol, dexamethasone suppression, and even hair cortisol—are used in practice. Drawing on evidence about free cortisol measurement and the advantages of mass spectrometry over traditional immunoassays, it highlights why the right laboratory method matters. You’ll also learn how Doctors365 provides secure, specialist-led telehealth so experienced endocrinologists can select appropriate tests, interpret your results, and coordinate follow-up care from the comfort of your home.

Disclaimer: This article is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or emergency care. Always consult a qualified clinician for personal medical guidance or if you are worried about your symptoms.

Author: Dr. Diellza Rabushaj

Cortisol is often called the “stress hormone,” but its role goes far beyond stress. It helps regulate blood pressure, blood sugar, immune function, metabolism, and the sleep–wake cycle. When cortisol is persistently elevated, it can damage tissues, raise cardiovascular risk, and signal conditions such as Cushing’s syndrome or long-term steroid overuse.[1–3]

Because cortisol is secreted in pulses, follows a strong day–night rhythm, and is mostly bound to proteins in the blood, a single random test rarely tells the whole story.[1,3] Modern diagnostic strategies focus on free cortisol (the biologically active fraction) and use specific tests in saliva, urine, blood, and even hair.[1–5]

In this guide, you’ll learn:

• What high cortisol actually means
• Which symptoms should raise suspicion
• The pros and cons of key tests (late-night salivary cortisol, 24-hour urinary free cortisol, low-dose dexamethasone suppression, hair cortisol)
• Why mass spectrometry is increasingly preferred over traditional immunoassays in Cushing’s syndrome work-ups[2,3]
• How Doctors365 endocrinologists can safely assess you online, order appropriate tests, and guide next steps

2. What is cortisol and what does “high cortisol” mean?

Cortisol is a glucocorticoid hormone produced by the adrenal cortex under control of the hypothalamic–pituitary–adrenal (HPA) axis.

Key features:[1,3]

• Circadian rhythm:
  • Peaks in the early morning
  • Falls to its lowest levels late in the evening and around midnight
• Ultradian (pulsatile) secretion throughout the day
• Protein binding: most circulating cortisol is bound to cortisol-binding globulin (CBG) and albumin; only a small free fraction is active at the receptor level

“High cortisol” can mean:

• True hypercortisolism (Cushing’s syndrome): autonomous overproduction of cortisol from the adrenal glands (ACTH-dependent or independent)
• Exogenous hypercortisolism: due to glucocorticoid medications (oral, injected, inhaled, topical)
• “Functional” or stress-related hypercortisolism: due to chronic stress, depression, alcoholism, severe obesity or systemic illness, often called “pseudo-Cushing”[1–3]

The goal of proper testing is to distinguish pathological, sustained excess from normal or stress-related fluctuations.

3. Common causes of high cortisol (and when to suspect Cushing’s)

Possible sources of elevated cortisol include:

• Endogenous Cushing’s syndrome, such as:
  • Pituitary adenoma producing ACTH (Cushing’s disease)
  • Adrenal adenoma or carcinoma
  • Ectopic ACTH-producing tumors
• Exogenous glucocorticoids, prescribed or sometimes hidden in “supplements”
• Chronic stress or psychiatric conditions (e.g., major depression, anxiety disorders) influencing HPA-axis activity[1]
• Severe obesity, metabolic syndrome, uncontrolled diabetes, chronic alcohol use, or serious illness

You should particularly think of Cushing’s (pathologic hypercortisolism) if characteristic features like purple striae, proximal muscle weakness, spontaneous bruising, or very early osteoporosis appear together with resistant hypertension or diabetes.

4. Why diagnosing high cortisol is challenging

Several biological and technical factors complicate testing:[1–3]

• Cortisol levels change over minutes to hours → a single random blood value is rarely useful
• Most cortisol is protein-bound; free cortisol is the relevant fraction, but more complex to measure directly[1,3]
• Conditions that change CBG (pregnancy, estrogen therapy, liver disease, nephrotic syndrome) can distort total serum cortisol without changing free cortisol[1]
• Traditional immunoassays can cross-react with similar steroids and metabolites, potentially giving falsely high or low results[2,3]

For these reasons, guidelines emphasize:

• Screening with tests that reflect free cortisol over time (e.g., 24-hour urinary free cortisol, late-night salivary cortisol)
• Using cut-offs specific to each assay and laboratory
• Increasing reliance on mass spectrometry (LC-MS/MS, UHPLC-MS/MS) for greater specificity[1–3]

5. Key symptoms and signs that may trigger testing

Doctors typically consider cortisol testing when several of the following appear together:

• Rapid, unexplained weight gain with central (abdominal) fat distribution
• Round “moon” face or fat pad at the back of the neck (“buffalo hump”)
• Wide, purple stretch marks (striae) on the abdomen, thighs, or arms
• Easy bruising and slow wound healing
• Proximal muscle weakness (e.g., difficulty climbing stairs or rising from a chair)
• New or worsening high blood pressure or diabetes at a young age
• Menstrual irregularities, infertility, or reduced libido
• Mood changes: irritability, depression, anxiety, cognitive difficulties
• Recurrent infections or fractures from thin bones

Because many of these features also occur in common conditions (obesity, PCOS, chronic stress), testing is most helpful when clinical suspicion is moderate to high, not in people with vague or isolated symptoms.

6. First-line laboratory tests for high cortisol

Instead of random cortisol checks, endocrinologists rely on a set of validated screening tests:[1–3]

• Late-night salivary cortisol (LNSC) – typically measured between 23:00–00:00
• 24-hour urinary free cortisol (UFC) – at least one, often two collections
• Low-dose dexamethasone suppression test (LDDST) – usually 1 mg dexamethasone taken at night, blood cortisol measured the next morning

Each test has its own strengths and limitations, and many clinicians use two different tests to increase diagnostic confidence.[1–3]

Accurate interpretation depends heavily on the assay method used by the laboratory. Modern approaches increasingly favor LC-MS/MS or UHPLC-MS/MS, which reduce cross-reactivity and measurement variability compared with traditional immunoassays.[2,3]

7. Salivary cortisol and the body clock

Salivary cortisol reflects free cortisol because only the unbound fraction diffuses into saliva.[1,3,4] It is unaffected by CBG, making it an attractive marker of biologically active hormone levels.

7.1 How it’s measured

Kalman and Grahn showed that salivary cortisol can be measured with a simple enzyme immunoassay (EIA): collection is non-invasive, painless, requires only basic lab equipment, and can be completed in a few hours.[4] Their work highlights why saliva is so useful for teaching circadian rhythms and stress responses.

More advanced laboratories use UHPLC-MS/MS or LC-MS/MS to quantify cortisol and related steroids in saliva with higher specificity and accuracy.[3]

7.2 Late-night salivary cortisol (LNSC)

In healthy individuals, cortisol should be very low late at night. Loss of this night-time nadir is one of the earliest changes in Cushing’s syndrome.[1–3]

LNSC is therefore widely used because it:[1–3]

• Is easy to collect at home at the correct time
• Reflects the free, active hormone
• Picks up the loss of circadian rhythm, which is a key feature of pathological hypercortisolism

However, shift work, poor sleep hygiene, improper sampling time, and some medications can affect results. Oral contamination, bleeding gums, or topical steroid contamination also risk false readings, especially with immunoassays.[1–4]

8. 24-hour urinary free cortisol (UFC) and blood cortisol

8.1 24-hour urinary free cortisol (UFC)

UFC reflects the amount of free cortisol filtered by the kidneys over 24 hours and is a standard part of Cushing’s syndrome screening.[1–3]

Key points:[1–3]

• At least one, often two complete 24-hour collections are recommended
• UFC correlates with average daily free cortisol exposure
• Significant increases (often >3× upper limit of normal) strongly support hypercortisolism

Traditional immunoassays can overestimate UFC due to cross-reactivity with cortisol metabolites and other steroids.[2,3] Mass spectrometry methods greatly improve specificity.[2,3]

8.2 Serum cortisol and free cortisol

Total serum cortisol is influenced by CBG and albumin, so it may not reflect the true free hormone level when CBG is altered.[1]

Choi emphasizes that free cortisol is the clinically relevant parameter and reviews methods such as equilibrium dialysis combined with LC-MS/MS to measure it directly, though these are technically demanding and less available.[1] In real-world practice, serum cortisol is mainly used in suppression tests (like the low-dose dexamethasone test) rather than as a random screening tool.[1–3]

9. Immunoassay vs mass spectrometry: why the method matters

Not all cortisol tests are created equal.

• Immunoassays (e.g., EIA, chemiluminescent assays)
  • Widely available, automated, relatively fast and inexpensive
  • Vulnerable to cross-reactivity with structurally similar steroids and metabolites
  • Can lead to false positives or negatives, especially in complex patients or those taking multiple steroids[2,3]
• Mass spectrometry (LC-MS/MS, UHPLC-MS/MS)
  • Separates and quantifies individual steroids, providing higher analytical specificity and accuracy
  • Reduces inter-laboratory variability and platform-to-platform differences[2,3]
  • Particularly beneficial in diagnosing Cushing’s syndrome, where false positives carry major consequences[2]

McWhinney and colleagues developed a UHPLC-MS/MS method to simultaneously measure cortisol, cortisone, prednisolone, dexamethasone, and 11-deoxycortisol in plasma, plasma ultrafiltrate, urine, and saliva, validating it against immunoassay and HPLC.[3] Casals and Hanzu specifically conclude that mass spectrometry is more accurate and reliable than immunoassays for measuring cortisol in Cushing’s syndrome, reducing variability and false positives in screening.[2]

Choi’s review further supports a shift toward comprehensive, MS-based assays for free cortisol measurement in adrenal disorders.[1]

10. Hair cortisol: a window into long-term exposure

Unlike blood or saliva, which capture moment-to-moment fluctuations, hair cortisol offers a retrospective index of long-term cortisol exposure over weeks to months.[5]

Russell and colleagues led the first international inter-laboratory round robin on hair cortisol measurement, showing that results from different labs and methods (immunoassay vs LC-MS/MS) are highly correlated and can be standardized using correction factors.[5]

Clinical implications:[5]

• Hair cortisol is promising for assessing chronic stress or prolonged hypercortisolism, including possible cyclical Cushing’s
• It is not yet a standard first-line diagnostic test, but it is gaining traction as a supportive biomarker
• Standardization efforts are key if hair cortisol is to move from research into routine diagnostic pathways

For most patients being evaluated for high cortisol, hair cortisol is currently a complementary rather than primary test.

11. Interpreting results: from screening to a firm diagnosis

Once screening tests suggest pathological hypercortisolism, the next steps typically include:[1–3]

1. Repeat or confirm abnormal tests – to rule out lab error or transient stress effects
2. Measure ACTH – to differentiate ACTH-dependent from ACTH-independent causes
3. Further dynamic tests – such as high-dose dexamethasone suppression or CRH stimulation, in specialized settings
4. Imaging – pituitary MRI, adrenal CT, or searches for ectopic ACTH-producing tumors, guided by endocrinology

Because each test has false positives and negatives, interpretation must consider:

• Medicines (especially glucocorticoids, opioids, some psychiatric drugs)[2,3]
• Comorbidities (depression, alcohol use, obesity, severe illness) that can mimic Cushing’s in both biochemistry and appearance[1–3]
• Laboratory method (immunoassay vs mass spectrometry) and local reference ranges[1–3]

This is why self-ordered testing without specialist support can be confusing and anxiety-provoking.

12. Why medical oversight matters for cortisol testing

Working with an experienced endocrinologist helps you:

• Decide whether testing is really needed (and avoid unnecessary anxiety or over-testing)
• Choose the right tests and timing (e.g., late-night saliva vs UFC vs dexamethasone suppression)[1–3]
• Interpret abnormal results in context of your medications, health conditions, and lab methods[1–3]
• Distinguish true Cushing’s syndrome from pseudo-Cushing states like severe stress or alcoholism
• Plan safe follow-up: imaging, further dynamic testing, or referral for surgery where indicated

Mass-spectrometry-based methods are more available in specialized or central laboratories,[1–3] so an endocrinologist who understands these nuances can help ensure you are tested in the right place with the right technology.

13. How Doctors365 works (step-by-step)

Getting expert help for possible high cortisol through Doctors365 is straightforward:

1. Browse verified endocrinologists and other relevant specialists on doctors365.org
2. Pick a time that fits your schedule (including evenings and weekends, depending on the doctor)
3. Confirm & pay via secure online checkout
4. Join your visit via encrypted video—no extra apps or complicated setup needed
5. Receive a visit summary, electronic prescriptions, and lab referrals when clinically appropriate

Your doctor can:

• Review your symptoms and risk factors
• Decide which cortisol tests are appropriate (if any)
• Provide clear instructions for timing and collection
• Interpret results and guide further imaging or referrals if needed

14. Benefits of Doctors365 for hormone and adrenal concerns

Patients with suspected high cortisol often face multiple visits and long waits. Doctors365 helps by offering:

• 24/7 access to experienced specialists across 28+ departments
• Privacy and discretion, with encrypted video and secure records
• Convenience and reduced costs, by avoiding unnecessary trips and time off work
• Continuity of care, including follow-ups to adjust testing and treatment plans
• Multilingual support, with doctors in 11+ languages

This model is particularly well suited to chronic hormone issues, where careful history-taking, result interpretation, and ongoing monitoring matter as much as a single physical exam.

15. Quality & trust at Doctors365

Doctors365 emphasizes:

• Verified specialists: every doctor’s qualifications and credentials are checked
• Clinical governance: endocrinology and internal medicine care is aligned with current evidence and best practices in cortisol measurement and Cushing’s syndrome work-up, including the growing role of mass spectrometry.[1–3]
• Data security: encrypted communication, secure storage of health information, and protected payment systems

The platform also offers a Second Opinion Service and membership options for those needing repeated follow-up.

16. Meet our endocrinology specialists (featured)

These Doctors365 specialists are experienced in adrenal and metabolic disorders, including suspected high cortisol and Cushing’s syndrome:

• Dr. Ivica Smokovski — Endocrinology
• Dr. Tomo Lucijanic — Endocrinology
• Dr. Hala Ahmadieh — Endocrinology

They provide:

• Detailed history-taking focused on cortisol symptoms and medication exposure
• Guidance on which tests (salivary, urinary, serum, hair) are appropriate
• Interpretation of results with awareness of assay type (immunoassay vs mass spectrometry)[1–3]
• Long-term follow-up and coordination with local imaging or surgical services if needed

You can browse their profiles and book securely via doctors365.org.

17. What’s online-appropriate vs in-person or emergency care?

Online endocrinology is excellent for many aspects of cortisol evaluation, but not everything can or should be handled remotely.

Suitable for online care:

• Initial evaluation of symptoms and risk factors for high cortisol
• Deciding whether and how to test (saliva, urine, blood, hair)
• Explaining results and planning follow-up investigations
• Monitoring after treatment for Cushing’s syndrome
• Addressing stress, sleep, and lifestyle factors that interact with HPA-axis function

Requires in-person or urgent care:

Seek urgent in-person medical review or emergency care if you experience:

• Severe, sudden weakness, confusion, or collapse
• Very high blood pressure with chest pain, shortness of breath, or severe headache
• Signs of serious infection (high fever, shaking chills, severe shortness of breath)
• Rapidly progressive swelling of the face, tongue, or throat, or trouble breathing

If you are already on steroids and suddenly feel extremely unwell (e.g., vomiting, abdominal pain, dizziness), you may be at risk of adrenal crisis if doses are changed abruptly—this is an emergency situation. Always call local emergency services in life-threatening situations.

18. Pricing & availability

Doctors365 aims to keep specialist care accessible and transparent:

• Online consultations typically start around a moderate fee range (exact amounts vary by doctor and country)
• Flexible slots, including evenings and weekends, depending on specialist availability
• Options for single consultations, Second Opinion Service, and membership for ongoing care

You can see live pricing and available times directly on each doctor’s page at doctors365.org.

19. Practical tips: preparing for your online cortisol consultation

To get the most from your visit:

• Write down your symptoms, when they started, and how they have changed
• Note any weight changes, blood pressure readings, or new diagnoses (diabetes, high cholesterol, osteoporosis)
• List all medications and supplements, especially any form of steroid (pills, injections, inhalers, nasal sprays, creams)
• Gather recent lab results or imaging if available
• Think about your sleep patterns, stress levels, alcohol use, and menstrual history (if applicable)
• Prepare questions such as:
  • Do I really need cortisol testing?
  • Which test is most appropriate for me?
  • How accurate are these tests, and what can affect the results?
  • What happens if my results are borderline or abnormal?

Having this information ready helps your doctor quickly assess whether high cortisol is likely and which tests, if any, are warranted.

20. Ready to get answers? (CTAs)

• Worried about high cortisol or Cushing’s?
  Start by booking a secure online consultation with a Doctors365 endocrinologist. They can help you decide if testing is necessary and guide you through the safest, most accurate options.
• Already have abnormal cortisol results?
  Upload your reports and schedule a Second Opinion with one of our featured endocrinologists for a clear explanation and step-by-step plan.

Visit doctors365.org to browse endocrinologists and book your appointment today.

21. Conclusion

High cortisol is more than just a “stress hormone issue.” Persistent hypercortisolism can indicate serious health problems such as Cushing’s syndrome, but it can also be mimicked by common conditions and everyday stress. Because cortisol is pulsatile, circadian, and mostly protein-bound, diagnosis relies on carefully chosen tests and high-quality assays rather than single random measurements.[1,3]

Advances in laboratory science—especially the rise of mass spectrometry for cortisol and related steroids—are making diagnosis more accurate and reducing false positives.[1–3] Salivary, urinary, and hair cortisol each offer different windows into hormone exposure over minutes, hours, and months.[1,3–5]

With Doctors365, you can access experienced endocrinologists who understand both the clinical and technical sides of cortisol assessment and can coordinate appropriate testing, interpretation, and follow-up—all through a secure, convenient online platform.

If you’re concerned about high cortisol, the next step is simple: book a secure video consultation and get expert guidance tailored to you.

22. FAQs

1) Can I diagnose high cortisol with a single blood test?
No. A random cortisol test is rarely helpful because cortisol fluctuates throughout the day and most is bound to proteins.[1,3] Proper diagnosis uses validated tests such as late-night salivary cortisol, 24-hour urinary free cortisol, or dexamethasone suppression, interpreted by an experienced clinician.[1–3]

2) Is late-night salivary cortisol reliable?
Yes—when collected correctly. Salivary cortisol reflects free cortisol and is unaffected by binding proteins, making it a good marker of the loss of the normal night-time cortisol nadir.[1,3,4] It must be collected at the correct time and analyzed with a validated assay (ideally mass spectrometry).[2–4]

3) Why do doctors prefer mass spectrometry over standard cortisol immunoassays?
Immunoassays can cross-react with similar steroids and metabolites, sometimes giving falsely high or low readings.[2,3] Mass spectrometry (LC-MS/MS, UHPLC-MS/MS) provides higher specificity and accuracy and is particularly valuable in Cushing’s syndrome screening.[1–3]

4) What is hair cortisol and do I need it?
Hair cortisol is an emerging marker that reflects long-term cortisol exposure over weeks to months.[5] Research shows that results from different labs can be standardized using correction factors.[5] It is not usually a first-line clinical test but may be useful in selected cases or research settings.

5) Can I order my own cortisol tests online without seeing a doctor?
While direct-to-consumer tests exist, cortisol interpretation is complex and can easily be misleading. Factors such as stress, medications, illness, assay method, and sampling errors all affect results.[1–3] It’s safer to work with an endocrinologist who can choose the right tests, interpret them correctly, and plan next steps.

23. References

1. Choi MH. Clinical and technical aspects in free cortisol measurement. Endocrinol Metab (Seoul). 2022.
2. Casals G, Hanzu FA. Cortisol measurements in Cushing’s syndrome: Immunoassay or mass spectrometry? Ann Lab Med. 2020.
3. McWhinney BC, Briscoe SE, Ungerer JPJ, Pretorius CJ. Measurement of cortisol, cortisone, prednisolone, dexamethasone and 11-deoxycortisol with ultra high performance liquid chromatography-tandem mass spectrometry: Application for plasma, plasma ultrafiltrate, urine and saliva in a routine laboratory. J Chromatogr B Analyt Technol Biomed Life Sci. 2010.
4. Kalman BA, Grahn R. Measuring salivary cortisol in the behavioral neuroscience laboratory. J Undergrad Neurosci Educ. 2004.
5. Russell E, Kirschbaum C, Laudenslager ML, Stalder T, de Rijke YD, et al. Toward standardization of hair cortisol measurement: Results of the first international interlaboratory round robin. Ther Drug Monit. 2015.