High cortisol: symptoms, what raises it and what tests to ask for

If you searched for «high cortisol symptoms», you are probably tired, you have gained weight without a clear explanation, or you have read that stress «spikes cortisol». Online the two ideas get mixed up, and it helps to separate them from the start. Everyday stress raises cortisol while it lasts, and that is part of the body's normal response;^[4][10] cortisol that stays high over a long time is called Cushing syndrome, and it is uncommon.^[3] Here is what cortisol is, why its daily rhythm means a single morning blood test says little, what raises it and in which direction, which tests doctors use, and what you can measure at home in the meantime.

Stress and high cortisol are not the same thing

Cortisol is a hormone made by the adrenal glands, which sit on top of the kidneys,^[4] and one of its jobs is to help the body respond to stress.^[3] When facing a challenge or a demand, the body releases hormones that make the brain more alert, tense the muscles and speed up the pulse.^[10] Acute stress is short-term and goes away quickly; chronic stress lasts weeks or months, like money or work problems.^[10] Cortisol takes part in both, and its rise in those situations is not a disease.

Cushing syndrome is something else: the body has too much cortisol over a long period.^[3] When the cause is inside the body, for example a tumor of the pituitary or of an adrenal gland, usually non-cancerous,^[8] it is estimated to affect about 40 to 70 people per million; it is most common between ages 30 and 50 and affects about three times as many women as men.^[3] But the most common cause of all is not a tumor: it is the long-term, high-dose use of corticosteroids, medicines similar to cortisol.^[3][7]

Between a bad month and Cushing syndrome there is a middle ground. Heavy drinking, depression or anxiety, obesity and poorly controlled diabetes can keep cortisol high without causing the long-term effects of the syndrome; doctors call this pseudo-Cushing.^[3] The Endocrine Society guideline lists those conditions together with pregnancy, the physical stress of a hospital stay, surgery or pain, malnutrition and sustained intense exercise.^[1] The 2021 consensus adds polycystic ovary syndrome, and explains that when the underlying condition, such as depression, is addressed, the hormonal axis usually returns to normal.^[2]

Cortisol keeps a schedule

In someone who sleeps at night, cortisol starts rising between 3 and 4 a.m., peaks between 7 and 9 a.m. and falls to very low levels around midnight, if the person is calm and asleep.^[1] That is why, when a doctor wants to see the rhythm in blood, they often order two draws on the same day: one in the morning, when the level is highest, and one around 4 p.m., when it is much lower.^[4]

This schedule explains almost everything that follows. In Cushing syndrome the most consistent abnormality is the loss of the nighttime low: cortisol does not drop as it should.^[1] So a morning result, taken at the peak, says little, and the guideline does not recommend a random blood cortisol to look for the syndrome.^[1] Chronic stress distorts the curve in a different way: the nighttime low rises, the morning peak falls and the rhythm flattens.^[9]

High cortisol: the symptoms doctors take into account

The symptoms of sustained excess cortisol are characteristic when they appear together: weight gain, a round face, fat at the base of the neck and between the shoulders, thin arms and legs, easy bruising, wide purple stretch marks, weak muscles, high blood pressure and glucose, bone loss and mood changes.^[3] The British health service adds a red face, irregular periods, excess hair growth and low sex drive,^[8] and MedlinePlus adds thin skin, frequent infections, fatigue and increased thirst.^[7]

The practical problem is that many of those symptoms are common for other reasons: gaining weight, feeling tired, having high blood pressure or glucose. That is why the Endocrine Society guideline separates the features that best discriminate the syndrome from what is common in the general population:^[1]

• Easy bruising, with no bumps to explain it.^[1]
• A red, full face (what doctors call facial plethora).^[1]
• Weakness in the muscles close to the trunk: thighs and shoulders, the kind you notice climbing stairs or getting up from a chair.^[1]
• Reddish-purple stretch marks more than 1 cm wide.^[1]
• In children, weight gain with slower growth.^[1]

The guideline recommends testing cortisol in four situations: features unusual for age, such as osteoporosis or high blood pressure in a young person; several features that keep increasing; children whose growth slows while they gain weight; and an adrenal nodule found by chance on a CT scan.^[1] The 2021 consensus is candid about the limit: there is no single preferred test and no agreement on when to test, and the doctor's clinical judgment carries a lot of weight.^[2]

If what brought you here is tiredness, also see which tests to ask for when you are tired all the time; if it is weight that will not come off, this article on weight lays out the measurements to sort out first.

What each cortisol test measures

When a doctor suspects excess cortisol, the Endocrine Society guideline recommends starting with one of three tests: 24-hour urine free cortisol, late-night salivary cortisol or an overnight suppression test.^[1] The 2021 consensus leaves the choice to what is available locally,^[2] and in practice two different tests are usually used to confirm.^[3] The table summarizes what each one shows; doses, exact times and preparation are set by the doctor or the laboratory.

For any of them it helps to arrive rested, because stress and exercise raise cortisol; for saliva, do not eat, drink or brush your teeth in the 30 minutes before; and mention all your medicines, including skin creams, without stopping any on your own.^[4] For blood and urine, the laboratory may ask you to avoid vigorous exercise the day before.^[5][6]

What does a morning cortisol of 18, 25 or 30 mean?

A cortisol of 18 µg/dL in an 8 a.m. sample is within the usual range of 5 to 25 µg/dL; 25 is at the upper limit and 30 is above it, but none of the three, on its own, tells whether there is Cushing syndrome.^[5][1] At that hour cortisol is at its peak, stress and acute illness raise it,^[5] estrogens raise it in blood,^[1] and ranges vary slightly between laboratories.^[5] It is a good example of why the lab reference range is not your personal normal.

The table sorts the cutoffs given by the sources of this article. Those for the saliva, urine and suppression tests are criteria your doctor applies within a process that includes your symptoms and medicines: they are not meant to be read at home.

What raises cortisol and in which direction

What raises cortisol without disease of the gland is on two lists: the guideline's list of conditions with high cortisol but no syndrome^[1] and the MedlinePlus list of factors that change the result.^[4] How they raise it also matters, because each factor affects a different test:

Corticosteroids in any form

Corticosteroids are used for asthma, arthritis, lupus or after a transplant,^[3] and they are the most frequent cause of excess cortisol.^[7] The guideline asks doctors for a full history of their use by any route, oral, rectal, inhaled, on the skin or injected, and warns that creams, some herbal products and joint or nerve injections are easily forgotten.^[1] The direction is surprising: because the body slows its own production, urine cortisol can come out low.^[6] And stopping a corticosteroid suddenly can be dangerous: any change is made by the doctor.^[7]

Oral contraceptives, pregnancy and the protein that carries cortisol

In the blood, cortisol travels partly bound to a carrier protein. Estrogens, including those in oral contraceptives, increase that protein, and blood cortisol comes out falsely high: about half of women on the pill have a false positive on the suppression test.^[1] Urine is not affected by this,^[1] and the consensus considers that test unreliable with oral estrogens.^[2] If it needs repeating, the guideline suggests withdrawing estrogens weeks beforehand when possible,^[1] always as a medical decision. Pregnancy also raises cortisol;^[1] which other results change with the cycle is covered in menstrual cycle and lab results.

Sleep, shifts and travel

Short sleep is associated with more activity of the stress axis in the afternoon and evening, and chronic insomnia with high evening cortisol; an activated axis, in turn, makes sleep harder.^[9] With night shifts or frequent travel across time zones the curve may shift, although the authors present this as a hypothesis.^[9] That is why the consensus advises against late-night saliva in people who work nights and suggests collecting it at the usual bedtime.^[2] After a long trip, a cold or a hard week, how many days the body takes to recover explains how to measure the return.

What to measure at home for two weeks

You do not measure cortisol at home on your own: even the saliva sample, which is collected at home, is ordered by the doctor.^[4] What you can measure is the context that excess cortisol affects, such as blood pressure and glucose,^[3] and what moves it most without disease, such as sleep and stress.^[9] Two weeks are enough to see a pattern:

1. Sleep: bedtime and wake time, how many times you woke up and how you felt in the morning. If you wear a watch, add hours of sleep, resting heart rate and heart rate variability (HRV), which we explain in that article.
2. Stress from 0 to 10 every evening, with one line on what caused it. Stress that lasts weeks is not the same as a bad week,^[10] and the diary tells them apart.
3. Alcohol, caffeine and intense exercise, with dates and approximate amounts: exercise and heavy drinking are among the things that move cortisol.^[4][3]
4. Weight and waist once a week, fasting, at the same time. Fat that concentrates in the belly, face, neck and upper back is one of the features described in excess cortisol.^[3][8]
5. Home blood pressure for seven days, morning and evening, with the technique in our blood pressure guide. High blood pressure is one of the effects of excess cortisol.^[3]
6. Fasting glucose on three mornings, if you have a meter; high fasting glucose explains how to read it, and if you get sleepy after eating, note that too.
7. Medicines: everything you use, including corticosteroids as creams, inhalers, drops or injections, and contraceptives, with start dates.^[1][6]

Cortisol tests are repeated when the doctor says so. For 24-hour urine or late-night saliva it is normal to be asked for two or three samples, because cortisol varies from day to day,^[2] and urine is sometimes repeated over weeks or months.^[6]

Warning signs

Almost everything in this article can be sorted out calmly over two weeks. What does call for action without waiting for the log is this:

• Thoughts of harming yourself or of suicide, yours or someone close to you: call 911 or your local emergency number, or go to the emergency room. Do not put it off.^[10]
• Panic symptoms such as dizziness, rapid breathing or a racing heart, fears you cannot control, or stress that keeps you from working or functioning: seek professional help soon.^[10]
• If you use a corticosteroid, do not stop it suddenly even if you suspect it is affecting you: stopping it abruptly can be dangerous. Call your doctor to adjust it.^[7][4]
• Several of the features that best discriminate the syndrome, such as easy bruising, wide purple stretch marks, a round red face or weakness in the thighs and shoulders, appearing together and increasing: see a doctor in the coming weeks, not at your next check-up.^[1][8]
• Changes that do not fit your age, such as a bone broken from a minor bump or high blood pressure in a young person: this is one of the situations in which the guideline recommends testing.^[1] If your home blood pressure comes out very high, the urgent steps are in our blood pressure guide.

What to bring to the doctor

If you arrive with only the feeling of being tired, the appointment is decided on little information. This changes it:

1. The full list of medicines, including corticosteroids in any form (pills, injections, joint injections, inhalers, creams, drops), contraceptives or other estrogens, and herbal products.^[1]
2. When the changes began in weight, skin, strength, mood or periods, and whether they are increasing.^[1][8]
3. The two-week diary: sleep, stress, alcohol, caffeine and exercise, and whether you work nights or shifts.^[2][9]
4. Seven days of blood pressure, weight, waist and glucose, with dates.^[3]
5. Previous results: any cortisol you have had measured, with the time of the draw, and your latest glucose, HbA1c and lipid tests.^[5][7]
6. History: current pregnancy, depression or anxiety, fractures, high blood pressure that started young.^[1]

With that, your doctor decides whether cortisol needs testing and which test to start with.^[2] How to turn those observations into a concrete question is explained in what health hypotheses are.