How to Test Cortisol Levels: FAQ Guide

Published January 9, 2025

Cortisol is known as “the stress hormone”¹ for its role in regulating the body’s stress responses. In addition to this important function, cortisol affects nearly all the body’s organs, tissues and systems. Your body produces cortisol to help carry out many essential functions — everything from controlling blood pressure and blood sugar levels to regulating the metabolism — with levels of cortisol normally fluctuating throughout the day.²

Having too much or too little cortisol can affect the critical bodily functions it helps regulate. That’s why it’s crucial to understand how to check cortisol levels. This article will discuss what you need to know about cortisol testing — why you should get tested, testing options and what to do after your test. 

Why check cortisol levels?

Having levels of cortisol that are either too high or too low can be signs of serious health conditions. If your cortisol levels are too high, you could notice symptoms such as:

• High blood pressure
• High blood sugar, which can increase your risk for Type 2 diabetes
• Stretch marks on the abdomen (belly)
• Weak bones, which could lead to fractures
• Weight gain

Abnormally high cortisol levels could be a sign of a rare condition called Cushing syndrome² (also known as hypercortisolism). Without treatment, Cushing syndrome can lead to many conditions and issues, including:

• Blood clots, especially in the legs and lungs
• Heart attack
• High blood pressure
• High cholesterol
• Type 2 diabetes

Left untreated, Cushing syndrome can be fatal.³ 

Cortisol levels that are too low can cause different symptoms, such as:

• Fatigue (feeling tired)
• Low blood pressure
• Loss of appetite
• Unexplained weight loss²

Abnormally low cortisol levels can also be dangerous. This is called adrenal insufficiency, and it can result from:

• Addison’s disease, also known as adrenal insufficiency (a rare condition in which the body doesn’t produce enough cortisol, most often because the body’s immune system attacks the glands that produce it)⁴
• An underactive pituitary gland or a tumor of the pituitary gland
• Having recently stopped taking corticosteroid medications²

Common reasons for testing cortisol levels include:

• Stress management (excess stress can lead to higher-than-normal levels of cortisol)²
• Possible diagnosis of Cushing syndrome or Addison’s disease
• Athletic performance training (excess cortisol can contribute to muscle atrophy)⁴

What tests measure cortisol levels?

There are several ways to measure cortisol levels. These include:

• Cortisol blood test: The most common testing option for cortisol, this involves taking a small sample of blood in the morning (when cortisol levels are at their highest)
• Cortisol saliva test: This involves taking a sample of your saliva (spit) with a special swab
• Cortisol urine test: This test involves a healthcare provider measuring cortisol levels in all the urine you produce over 24 hours

Each testing method has its advantages. Quest uses the blood test for cortisol measurement. The blood test is easy and convenient, and it doesn’t require special collection methods. That makes it ideal for most people who need a cortisol test.

How should you prepare for a cortisol test?

Understanding cortisol test timing and preparation is important. Your testing will take place between the hours of 7 and 9 a.m. You do not need to fast before your test, though you should limit any strenuous exercise the day before your test. Your healthcare provider may also ask you to not take certain medications that can affect the test results, such as:

• Androgens
• Anti-seizure medication
• Estrogen
• Hydrocortisone
• Prednisolone
• Prednisone⁵

What do your cortisol test results mean?

If you’re active during the day and sleep at night, normal range for cortisol levels should be between 10 and 20 micrograms per deciliter (mcg/dL) between 6 and 8 a.m.² If your cortisol levels are too high or too low, you may need repeated testing or additional tests to determine the cause. You will need to talk about your test results with a healthcare provider to determine the next steps.

If your cortisol levels are too high and the result of Cushing syndrome, treatment usually involves medications, surgery or both to treat the cause.³ If your cortisol levels are too low and the result of Addison’s disease, treatment often involves hormone therapy to replace the cortisol your body isn’t making, as well as other medications.⁶

Why buy your cortisol test online from Quest?

Quest offers convenient cortisol blood tests you can buy online. You don’t need a doctor’s visit — simply buy your test, schedule your sample collection, and get your results. After you receive your results, you can speak to an independent doctor to discuss any questions or concerns you may have.

Quest offers hormone testing in more than 2,000 locations, or you can schedule sample collection in your own home (if available in your area). Get the insights you need about your cortisol levels.

Buy your cortisol test

No doctor visit is required to buy your own lab test at questhealth.com. PWNHealth and its affiliates review your purchase to ensure it is medically appropriate before submitting the test order for processing. PWNHealth also reviews your test results and will contact you directly if they require prompt attention. Included in each purchase is the option to discuss your test results with an independent physician; however, you are also encouraged to speak with your primary healthcare provider.