Normal cortisol levels on a blood test are 10 to 20 mcg/dL between 6 a.m. and 8 a.m. and 3 to 10 mcg/dL around 4 p.m., according to Cleveland Clinic. Cortisol follows a daily rhythm, so a result only means something when you know what time the sample was taken. This guide gives you the ranges for blood, urine, and saliva tests, shows how the day’s pattern works, and explains what high and low results can mean.
Different sources set the morning range a little differently, and each lab prints its own reference range on your report. MedlinePlus lists 5 to 25 mcg/dL at 8 a.m. for a blood test, and its 24-hour urine test has separate cutoffs for women and men. If cortisol is already on your mind because of stress and weight, the post on how chronic stress drives weight gain covers the everyday side of this hormone.
Jump to: Cortisol Chart | Time of Day | Types of Tests | High Cortisol | Low Cortisol | What Skews Results | Habits That Help | FAQ
Normal Cortisol Levels Chart
Cortisol is a steroid hormone made by the adrenal glands. It helps with the stress response, controls how your body uses blood sugar for energy, reduces inflammation, helps regulate blood pressure, and helps control your sleep-wake cycle. The table below pulls together the adult reference ranges from Cleveland Clinic and MedlinePlus.
| Test | When or how collected | Normal range | Source |
|---|---|---|---|
| Blood | 6 a.m. to 8 a.m. | 10 to 20 mcg/dL | Cleveland Clinic |
| Blood | About 4 p.m. | 3 to 10 mcg/dL | Cleveland Clinic |
| Blood | 8 a.m. | 5 to 25 mcg/dL (138 to 690 nmol/L) | MedlinePlus |
| 24-hour urine, women | All urine over 24 hours | Less than 45 mcg/24 hours (124 nmol/24 hours) | MedlinePlus |
| 24-hour urine, men | All urine over 24 hours | Less than 60 mcg/24 hours (165 nmol/24 hours) | MedlinePlus |
| Saliva | Often late at night | No single standard range in these sources; use the range your lab reports | Cleveland Clinic, Mayo Clinic |
The two blood ranges overlap but are not identical, which is normal. Cleveland Clinic notes that normal ranges vary by lab, time, and person, so a borderline result may be flagged by one lab and not by another. The range printed on your own lab report is the one that applies to you. The sources above do not list separate ranges by age, so ask your provider if you are comparing a child’s or an older adult’s result.
Cortisol Levels by Time of Day
Cleveland Clinic explains that cortisol is usually highest in the early morning, falls through the day, and is lowest around midnight. Its hormone guide adds that levels peak in the morning before you wake up. That is why the blood ranges drop from 10 to 20 mcg/dL in the morning to 3 to 10 mcg/dL by about 4 p.m.
- Early morning: the peak, and the usual time for a single blood draw.
- Afternoon: a lower range, around 3 to 10 mcg/dL at about 4 p.m.
- Around midnight: the lowest point of the day, which is why a late-night saliva test is used to look for too much cortisol.
The pattern can shift. Cleveland Clinic notes that night-shift work can change it, and that testing may be repeated within one day or over several days because levels vary so much. One reading is a snapshot, not a verdict.
Blood, Saliva, and Urine Cortisol Tests
Each test captures something different, and your provider picks the one that fits the question.
- Blood: a quick draw from a vein in the inner arm, usually taking under five minutes and done in the early morning. It shows your level at one moment.
- Saliva: usually a take-home kit. You soak a swab in your mouth, then spit it into a container without touching the swab. Skip eating, drinking, brushing, flossing, smoking, and vaping for 30 minutes first.
- 24-hour urine: you discard your first morning urine, note the time, then collect everything for the next 24 hours, keeping the container cool. It shows the total amount your body released over a full day.
Results typically take one to five days. The National Institute of Diabetes and Digestive and Kidney Diseases says no single test is perfect for Cushing’s syndrome, so doctors usually use two of these: the 24-hour urinary free cortisol test, the late-night salivary cortisol test, and the low-dose dexamethasone suppression test. In the second, blood cortisol that fails to drop after dexamethasone points toward Cushing’s syndrome.
Preparation varies. MedlinePlus says you may be asked to avoid vigorous exercise the day before and to stop certain medicines for a while, including anti-seizure drugs, estrogen, synthetic glucocorticoids such as prednisone, and androgens. Never stop a prescribed medicine without your provider’s instruction.
What High Cortisol Can Mean
A result above the range has several possible explanations. Cleveland Clinic lists large doses of corticosteroids, a pituitary tumor making too much ACTH, an adrenal tumor making too much cortisol, and a tumor elsewhere in the body such as small cell lung cancer. MedlinePlus adds that stress or acute illness can raise a blood result, and that severe depression or severe stress can raise a urine result.
When the body makes too much cortisol over a long time, the condition is called Cushing’s syndrome. NIDDK reports that its most common cause is long-term, high-dose use of glucocorticoid medicines, which treat conditions such as asthma, rheumatoid arthritis, and lupus. Among cases not caused by medicine, pituitary tumors account for 8 out of 10. It affects roughly 40 to 70 people per million, usually between ages 30 and 50, and about three times as many women as men.
Cleveland Clinic lists these symptoms of high cortisol:
- Weight gain, especially in the face and belly
- Fatty deposits between the shoulder blades
- Wide, purple stretch marks on the belly
- Muscle weakness in the upper arms and thighs
- High blood sugar, which can progress to type 2 diabetes
- High blood pressure
- Excess hair growth in females
- Weak bones and fractures
Most people with belly weight gain do not have Cushing’s syndrome. NIDDK notes that not everyone with the condition has these symptoms, and Mayo Clinic points out that polycystic ovary syndrome, depression, eating disorders, and alcoholism can cause similar symptoms. If your waist is growing, measure it first with the normal waist size chart for women and men, then talk to your doctor if the other signs fit.
What Low Cortisol Can Mean
Low cortisol points the other way. Cleveland Clinic names primary adrenal insufficiency (Addison’s disease), often from an immune attack on the adrenal glands, plus secondary adrenal insufficiency from an underactive pituitary, and abruptly stopping corticosteroid treatment. MedlinePlus notes that glucocorticoid medicines, including pills, creams, eye drops, inhalers, and joint injections, can suppress the body’s own cortisol production.
The symptoms are fatigue, unintentional weight loss, loss of appetite, and low blood pressure. NIDDK explains that the ACTH stimulation test is the test used most often to diagnose adrenal insufficiency: blood is drawn before and 30 or 60 minutes after an injection of synthetic ACTH. A normal response is a rise in cortisol, while people with Addison’s disease show little or no rise. Tiredness alone has many other causes, so use the post on signs of adrenal fatigue as a symptom checklist to take to your doctor, not as a diagnosis.
What Can Skew Your Cortisol Result
Cleveland Clinic cautions that an abnormal result does not automatically mean you have a condition that needs treatment. Stress, physical activity, serious illness, temperature extremes, certain medications, and sleep can all change your level. Insomnia and night-shift work can raise cortisol, and the page notes you may be asked to rest beforehand so stress does not affect the result.
Follow-up testing is common. After an unexpected result, your provider may repeat the test, order a different type, or add an ACTH stimulation test, a dexamethasone suppression test, or an MRI or CT scan.
Everyday Habits That Support Healthy Cortisol
Cleveland Clinic names three habits that help: good sleep, regular exercise, and stress management such as deep breathing, enjoyable activities, laughter, and healthy relationships. These habits help with everyday stress, but Cushing’s syndrome needs medication, surgery, or both.
- Protect your sleep. Cleveland Clinic says insomnia and night-shift work can raise cortisol, so a steady bedtime is worth the effort.
- Move most days. Harvard Health says exercise reduces stress hormones such as adrenaline and cortisol, and suggests 30 to 40 minutes of moderate exercise like walking or 15 to 20 minutes of vigorous exercise. The guide to the best time of day to exercise for weight loss can help you plan it.
- Build a calming routine. Even a 20-minute stroll, breathing exercises, or meditation can take the edge off a hard day.
- Treat food as support. Cleveland Clinic’s cortisol guide does not address diet, so think of food as one supporting habit, not a fix. The list of foods that may help with chronic stress gives you ideas to try.
Cortisol also helps control how your body uses blood sugar. The guide to hunger hormones covers other hormones that shape appetite, and the chart of normal fasting insulin levels shows another number worth checking if your blood sugar runs high. Blood pressure is the third piece, so compare your readings with the normal blood pressure by age chart.
Frequently Asked Questions About Cortisol Levels
What is a normal cortisol level in the morning?
Cleveland Clinic lists 10 to 20 mcg/dL between 6 a.m. and 8 a.m., and MedlinePlus lists 5 to 25 mcg/dL at 8 a.m. Your lab’s own range is the one to use.
What is a normal cortisol level at night?
Cortisol is lowest around midnight, but the sources reviewed here do not give a single standard saliva or blood number for it. Ask your lab for its late-night range. A late-night saliva test is used to check whether cortisol fails to drop, which is a sign pointing toward Cushing’s syndrome.
Can stress alone cause a high cortisol result?
It can raise a result. MedlinePlus lists stress and acute illness among the causes of a higher-than-normal blood result, and Cleveland Clinic says stress and sleep can change your level. Resting before the test and repeating it, if your provider asks, helps separate a temporary spike from a real problem.
Does high cortisol cause belly fat?
Cleveland Clinic lists weight gain in the face and belly as a symptom of Cushing’s syndrome, where cortisol stays too high for a long time. Everyday stress is different and is covered in the chronic stress and weight gain guide. If you have several of the symptoms listed above, ask your doctor about testing.
How do you prepare for a cortisol test?
Follow the instructions you are given. Blood tests are usually done early in the morning, and MedlinePlus says you may be asked to avoid vigorous exercise the day before and to pause some medicines. For saliva, avoid eating, drinking, brushing, flossing, smoking, and vaping for 30 minutes.
What does low cortisol feel like?
Cleveland Clinic lists fatigue, unintentional weight loss, loss of appetite, and low blood pressure. These symptoms have many causes, so testing is how a doctor tells low cortisol apart from other conditions.
The Bottom Line
Normal cortisol is highest in the early morning, roughly 10 to 20 mcg/dL on a blood test, and falls to about 3 to 10 mcg/dL by late afternoon, with the lowest point around midnight. Because stress, sleep, illness, and medicines all move the number, one result rarely tells the whole story. Ask for the test that fits your question, follow the preparation steps, compare against your lab’s printed range, and let your doctor interpret anything that falls outside it.
This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Please consult your doctor to interpret your cortisol results.
