High cortisol shows up in your body long before most people think to test for it. The signs range from subtle (poor sleep, creeping weight gain around your midsection) to unmistakable (a rounded face, wide purple stretch marks). Recognizing the pattern is the first step, and specific lab tests can confirm what’s going on.
Early Signs You Might Notice First
The earliest clues tend to be things you’d chalk up to stress or aging. You gain weight around your belly and face even though your diet hasn’t changed. You sleep poorly, waking in the middle of the night or lying awake despite being exhausted. Anxiety ramps up for no clear reason, or you feel wired at bedtime when your body should be winding down.
These happen because cortisol follows a daily rhythm: it peaks in the early morning to wake you up, then gradually drops through the day, reaching its lowest point around midnight. When cortisol stays elevated, that rhythm flattens out. Your body never gets the “all clear” signal to relax. An overactive stress response can fragment your sleep, shorten your total sleep time, and feed a cycle of insomnia and daytime fatigue.
A flattened cortisol curve (where levels stay relatively steady instead of rising and falling) has been linked in research to depression, fatigue, cardiovascular disease, obesity, and weakened immune function. You don’t need dramatically high numbers for this pattern to cause problems. Even a blunted rhythm, where cortisol doesn’t drop enough at night, can disrupt how you feel day to day.
Physical Changes That Point to High Cortisol
When cortisol has been high for weeks or months, the body starts showing visible changes that are harder to explain away. The NIDDK lists these as hallmarks of prolonged excess cortisol:
- A round, fuller face sometimes called “moon face,” caused by fat redistribution
- Increased fat around the base of the neck and a fatty hump between the shoulders
- Wide purple or pink stretch marks on the abdomen, breasts, hips, thighs, and underarms
- Thin, fragile skin that bruises easily and heals slowly
The stretch marks deserve extra attention because they’re different from the pale, silvery marks you get from rapid weight gain or pregnancy. Cortisol-driven stretch marks are wider, often vividly purple or reddish, and they tend to cluster on the trunk rather than just the hips and thighs. The bruising and slow healing happen because excess cortisol breaks down collagen, the protein that gives skin its structure and strength.
Weight gain from high cortisol also has a specific pattern. Fat accumulates centrally, around the abdomen and upper back, while arms and legs may actually become thinner. This is partly because cortisol increases the availability of the hormone in fat tissue itself, creating a feedback loop that concentrates fat storage in those areas.
How High Cortisol Affects Blood Sugar and Metabolism
Cortisol’s original job is to flood your bloodstream with quick energy during a crisis. It does this by telling your liver to release glucose and by ramping up glucagon, the hormone that raises blood sugar. In people with chronically elevated cortisol, basal glucagon levels can rise by around 55%, with even larger spikes after eating protein.
At the same time, your cells become less responsive to insulin. You may have plenty of insulin circulating, but your body can’t ramp up its insulin response when blood sugar climbs after a meal. This combination of high glucose production and poor insulin sensitivity is the same pattern seen in type 2 diabetes. If you’ve been told your fasting blood sugar is creeping up or you’re “prediabetic” without an obvious dietary explanation, sustained cortisol elevation is one possible contributor.
Testing: What Gets Measured and What the Numbers Mean
If your symptoms fit the pattern, a few specific tests can measure whether cortisol is actually elevated. No single test is definitive on its own, so doctors typically use a combination.
Late-Night Salivary Cortisol
This is the most convenient screening test. You collect a saliva sample at home between 11 p.m. and midnight, when cortisol should be at its daily low. A normal result is below 100 ng/dL. In people with confirmed Cushing’s syndrome (the clinical condition caused by prolonged high cortisol), late-night salivary levels typically range from 100 ng/dL up to 6,000 ng/dL. Two abnormal late-night samples on separate nights strengthen the case significantly.
Morning Blood Cortisol
A blood draw taken between 6 a.m. and 8 a.m. measures cortisol at its natural peak. The normal range is roughly 10 to 20 mcg/dL. A result well above 20 mcg/dL in the morning, or any elevated reading outside the expected time window, raises suspicion. Keep in mind that stress, illness, and even the anxiety of having blood drawn can temporarily spike cortisol, so a single high reading isn’t always meaningful.
Dexamethasone Suppression Test
This test checks whether your body’s feedback loop is working. You take a small pill (a synthetic steroid) the night before, which should tell your brain to stop producing cortisol. The next morning, your blood is drawn. A normal response is a cortisol level below 1.8 mcg/dL. If your cortisol stays above 1.8 mcg/dL despite the medication, it suggests your body is overproducing cortisol and isn’t responding to the normal “shut off” signal.
24-Hour Urinary Cortisol
You collect all your urine over a full day, and the lab measures total cortisol output. This smooths out the natural ups and downs of cortisol through the day and gives a picture of overall production. It’s less convenient but useful for confirming what other tests suggest.
What Can Falsely Raise Your Results
Cortisol is notoriously reactive. Several things can push your levels up temporarily without meaning you have a cortisol disorder. Intense physical stress, acute illness, sleep deprivation, heavy alcohol use, and even shift work can all elevate results. Oral contraceptives raise the binding protein that carries cortisol in blood, which can make a standard blood test look high even when the active cortisol in your body is normal. Saliva and urine tests are less affected by this.
Depression and severe obesity can also produce mildly elevated cortisol that mimics Cushing’s syndrome on screening tests, a situation sometimes called “pseudo-Cushing’s.” This is one reason doctors rely on multiple tests rather than a single number, and why the pattern of your symptoms matters as much as any lab value.
Putting the Pieces Together
A single symptom or a single test result rarely tells the full story. The strongest signal comes from a cluster: central weight gain plus sleep disruption plus skin changes plus an abnormal late-night saliva test, for instance. If you recognize several of the patterns described here, the practical next step is a late-night salivary cortisol test or a morning blood cortisol, which can be ordered by a primary care doctor. If initial results come back elevated, you’ll likely be referred to an endocrinologist who can run the suppression test and pinpoint whether the excess cortisol is coming from the adrenal glands, the pituitary gland, or an external source like long-term steroid medication.