Cortisol Test – Everything You Need to Know

What is Cortisol?

Cortisol is a hormone made in the adrenal glands – a pair of organs that sit above the kidneys. Cortisol plays a role in several bodily functions including:

  • Breakdown of fats, carbohydrates, and proteins1
  • Stimulating glucose production in the liver1
  • Fighting infections with the immune response2
  • Maintaining blood pressure3

Additionally, cortisol is part of the body’s stress response system called fight or flight2.

When should you get a cortisol test?

Since cortisol is required by a number of crucial bodily functions, any disruption to its levels can have a profound impact on your wellbeing. This also creates a problem when it comes to identifying any obvious signs that tell you when to get a cortisol test.

Unfortunately, there are very few symptoms of unbalanced cortisol levels that are exclusive to cortisol problems. In general, if you deal with a lot of stress, either at home or at work, it is wise to monitor your cortisol levels to ensure that they are not causing you problems.

Can you get a cortisol test at home?

Yes. Our fingerprick home health test kit tests for 21 blood markers and includes a cortisol test.

There are quite a few other cortisol test providers in the market. However, we show how your cortisol levels might affect your overall health.

For instance, cortisol affects your mood, fitness, and immunity. It’s crucial to understand that our health cannot be assessed in the context of a single blood marker. At ElevateMe, we build a holistic profile of your health and wellness.

Effects of cortisol on health - ElevateMe
We put blood test results into context. Check out what your blood report would look like here.

What affects your cortisol levels?

Cortisol production varies depending on the time of day. Levels are highest in the morning hours and gradually decrease throughout the day. Finally, they arrive at their lowest levels in the late afternoon and evening1.

Major shifts in cortisol levels could be caused by two conditions: Addison’s disease and Crushing’s syndrome. Addison’s disease is a condition that causes low levels of cortisol. Whereas Crushing’s syndrome causes elevated cortisol levels. They are both signs of adrenal dysfunction.

However, there may as well be other reasons behind abnormal cortisol levels. Here are some factors that affect the production of cortisol in the body:

  • Exposure to heat or cold
  • Infection
  • Stress
  • Trauma
  • Exercise
  • Obesity
  • A debilitating disease1

What are the symptoms of high cortisol levels?

Having high levels of cortisol can cause the following symptoms:

  • Increased blood pressure
  • High blood sugar levels
  • Obesity
  • Fragile skin
  • Muscle weakness
  • Purple lines around the stomach1

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What are the symptoms of low cortisol levels?

Low levels of cortisol can cause the following symptoms:

  • Weight loss
  • Muscle weakness
  • Fatigue
  • Low blood pressure
  • Abdominal pain1

What’s the connection between stress and cortisol levels?

Cortisol is a part of the body’s response to physical or emotional stress1. It actively kicks in when the body is preparing to respond to a threat or a stressful situation by either fighting the issue or escaping the situation (flight). Cortisol’s role in this is to provide the body with a burst of energy to respond as quickly as possible2. It accomplishes this by redirecting energy from non-essential processes to the muscles and brain4.

The paused processes that cortisol redirects energy from include:

  • Digestion processes
  • Growth processes
  • Reproductive processes4

Cortisol will also respond to the threat by increasing:

  • The amount of sugar in the blood4
  • The amount of sugar used in the brain4
  • Tissue repair abilities4
  • Tightening the blood vessels from the redirected processes (To reduce the amount of blood in these areas.)5
  • Relaxing the blood vessels in the muscles (This ensures faster delivery of nutrients to the muscles are due to an increase in the bloodflow.)5

What kind of sample is required for a cortisol test?

There are 3 ways to test for cortisol: blood test, urine test, and saliva analysis1. Since cortisol levels naturally vary throughout the day, the timing of these tests is vital.

Saliva tests are carried out at night, where the levels would be near their lowest levels3. Unlike the urine test, which is tested on a sample that has been collected through a full 24 hour period1.

There are two options when it comes to the blood test for cortisol levels. One option is to carry out one blood test a day, which should be collected as close to 9am as possible1. A second blood test can be carried out if further information is needed to diagnose other issues. The second blood test can be done in the late afternoon, often around 4pm3. At ElevateMe we suggest the former.

Benefits of a blood test over urine test to check cortisol levels

Blood tests are carried out at specific points in the day. Whereas urine tests will assess and provide a picture of a full day’s worth of cortisol production1. However, the urine test may not be able to identify any specific issues with the control of cortisol.

Benefits of a blood test over a salivary test to check cortisol levels

A saliva test will identify cortisol levels at what should be the lowest levels of the day. This will help in checking if the body can control cortisol levels as it should. However, it does not provide a full picture of the varying levels throughout the day. Additionally, the saliva test only confirms the lowest levels, so there is no way of knowing if your peak levels were correct.

What are the normal values of cortisol in your body?

Due to the way the body needs cortisol levels to vary throughout the day, there is no pinpoint normal number. Instead, using the time of the blood test, there is a range of normal values. This is because not every test can be done at the same time and it is, therefore, harder to compare this.

Here’s a graph that shows the normal pattern of cortisol levels in black. The blue dots show the true results of healthy cortisol levels. This graph shows how these results are not completely on the curve but are still completely acceptable.

Graph showing the daily cycle of cortisol levels6

The most commonly used blood test is the morning one. At ElevateMe, we use a sample that is taken in the first 3 hours of waking up. This provides the clearest picture of cortisol levels.

According to the NHS, these levels should be between 119-618 nmol/L7. In reference to the graph above, this is equivalent to 4.31 μg/dl -22.4 μg/dl.

At ElevateMe, we use optimal ranges to track your blood tests in lieu of reference ranges. Reference ranges are numbers that any adult should ideally target. However, to truly thrive and live your best life, optimal ranges which are developed with the healthiest of individuals as the benchmark, are the way to go. You can learn more about the benefits of using optimal blood test ranges over reference blood test ranges here

The optimal range for cortisol levels is between 171-535 nmol/L.

What does it mean if you have a high cortisol test reading?

High cortisol levels can point to a number of factors that you might be up against.

The most obvious reason is that you are experiencing too much stress. Consistent stress increases cortisol levels. This is due to the body’s constant readiness for a flight or fight response1.

Cortisol is produced by the adrenal glands, but the levels are controlled by another hormone called Adrenocorticotropic hormone (ACTH). This hormone is made in the pituitary gland. So if either of the glands (adrenal or pituitary) develops any tumors, whether cancerous or not, the levels of cortisol could increase1.

What does it mean if you have a low cortisol test reading?

Low cortisol levels are not always a sign of being stress-free or healthy. There could be two main reasons behind low cortisol levels.

  • Damage to the adrenal glands will directly lower cortisol levels. This is known as primary adrenal insufficiency1. This includes underactive and damaged adrenal glands1.
  • Poor levels of the ATCH hormone could point to underactive pituitary glands or pituitary tumors1.

Can you control your cortisol levels with diet?

Having a balanced diet is always essential to maintaining a healthy body.

Unhealthy food can cause an increase in cortisol production. In fact, sugar intake is a trigger for cortisol production8. If you have a regular, high intake of sugar, your cortisol levels will be constantly elevated9.

However, sugar intake can be beneficial in moments of extreme stress10. If you are facing a threat, elevated cortisol levels are exactly what you need. Interestingly, sugar can be beneficial in times of stress when the cortisol need is increased.

Unfortunately, that’s one of the reasons behind stress eating. When your body detects a threat, it knows it needs more energy to be able to respond as fast as possible. This results in sugar cravings which in the long run have their own side effects.

Here is a list of foods that can be eaten at the onset of sugary cravings. Eating these instead of sugary foods will still provide your body with healthy sources of immediate energy. This will help reduce your overall cortisol levels if they are high.

  • Drinking water whilst exercising11
  • Dark chocolate12
  • Fruits – particularly bananas and pears13
  • Black tea & green tea14

Probiotics are bacteria found in yogurts. They are good for you. Prebiotics are foods that these bacterias consume. Increasing levels of both will also help reduce cortisol levels in your body15.

What else can you do to get your cortisol levels under control?

  1. Regulate your sleep
    Sleep deprivation leads to increased levels of cortisol16. Achieving your body’s daily sleep requirements will help your body control your cortisol levels. Tips to improve your sleep include: avoiding caffeine at night17, limiting screen lights at night18, and reducing distractions later in the night.
  2. Exercise Levels
    Working out has a positive impact on cortisol production. The body recognises physical activity and in response drives down cortisol levels at night19. Intense exercise causes an immediate spike in cortisol levels but burns off energy more efficiently19. Moderate exercise does not trigger this response but will still lead to reduced cortisol levels. Either way, exercise is a great way to control elevated levels of cortisol20.
  3. Stress Control
    Cortisol production will increase when the body detects stress in your body and mind. Being able to recognise your stress levels can be beneficial in avoiding stress before it engulfs you. Spotting warning signs of stress can include subconscious actions like toe-tapping or finger fidgeting. You can identify these early signs and take charge through various techniques like breathing exercises, listening to music, and other relaxation methods personal to you21,22.
  4. Being Happy!
    Being happy reduces cortisol levels23. It is important to indulge in a little self-care for your own health benefit! This can include having a pet, as studies show interactions with your pets increase happiness and reduce cortisol levels24. Laughing reduces cortisol levels too25. Ensure that you make time for yourself every day to do something that you enjoy.
  5. Supplements
    There are two supplements that may improve your cortisol levels. The first one is fish oil supplements26. The second supplement is Ashwagandha – an Indian herbal supplement that helps in reducing overall cortisol levels too27.

Improve your overall health and mood

Regularly checking your cortisol levels will help you give a picture of your stress levels. It will also help assess the stress management practices you already have. The ElevateMe health test assesses your cortisol levels periodically. You also get a personalised health dashboard to track all parameters that give you the health baseline necessary to live your best life.

If you are interested in finding out your health score, you can take this free health quiz and get personalised insight into your health.

Common myths about cortisol tests

Q. Is Cortisol the only stress hormone?

A. No. There are a total of 3: cortisol, adrenaline, and noradrenaline28.

Q. Will morning exercise affect my cortisol levels?

A. Possibly, it depends on the intensity of the exercise. Intense exercise causes an immediate spike in cortisol production. For this reason, it may be best to avoid the morning exercise session on the day of your test.

Q. Is there any medication that will affect my cortisol levels?

A. Yes. A handful of drugs alter cortisol levels in the way that they work. These include steroids29, drugs containing androgen, and phenytoin.

Are you stressed? 

Did you know 74% of adults in the UK have experienced stress to a point where they have felt overwhelmed or unable to cope. 

Take an ElevateMe blood test today to capture 21 blood test insights and track your sleep, fitness, energy, metabolism, cognition, mood, and immunity.

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1 Lab Tests Online. (2020). Cortisol Test. Available: https://labtestsonline.org.uk/tests/cortisol-test. Last accessed 05/05/2021.

2 Thau, L., Gandhi, J. & Sharma, S. (2021). Physiology, Cortisol. Last accessed 26/04/2021.

3 Medline. (N.D). Cortisol Test. Available: https://medlineplus.gov/lab-tests/cortisol-test/. Last accessed 26/04/2021.

4 Mayo, (N.D.), Chronic Stress Puts your Health at Risk, Last Accessed 26/04/2021

5 Whitworth, J., Williamson, P., Mangos, G. & Kelly, J. (2005). Cardiovascular consequences of cortisol excessVascular Health Risk Management . 1 (4), 291-299.

6 Hosseinichimeh, N., Rahmandad, H. & Wittenborn, A. (2015). Modeling the hypothalamus-pituitary-adrenal axis: A review and extensionMathematical Bioscience. 268 (..), 52-65.

7 NHS South Tees, N.D, Cortisol, Last accessed 26/04/2021

8 Iranmanesh, A., Lawson, D., Dunn, B. & Veldhuis, J. (2011). Glucose ingestion selectively amplifies ACTH and cortisol secretory-burst mass and enhances their joint synchrony in healthy menJournal of Clinical Endocrinology & Metabolism. 96 (9), 2882-2888.

9 Gyllenhammer, L., Weigensberg, M., Spruijt-Metz, D., Allayee, H., Goran, M. & Davis, J. (2014). Modifying influence of dietary sugar in the relationship between cortisol and visceral adipose tissue in minority youthObesity. 22 (2), 474-481.

10 Tryon, M., Stanhope, K., Epel, E., Mason, A., Brown, R., Medici, V., Havel, P. & Laugero, K. (2015). Excessive Sugar Consumption May Be a Difficult Habit to Break: A View From the Brain and BodyJournal of Clinical Endocrinology & Metabolism. 100 (6), 2239-2247.

11 Maresh, C., Whittlesey, M., Armstrong, L., Yamamoto, L., Judelson, D, Fish, K., Casa, D., Kavouras, S. & Castracane, V.. (2006). Effect of hydration state on testosterone and cortisol responses to training-intensity exercise in collegiate runnersInternational Journal of Sport Medicine. 27 (10), 765-770.

12 Wirtz, P., Kanel, R., Meister, R., Arpagaus, A., Treichler, S., Kuebler, U., Huber, S. & Ehlert, U. (2014). Dark Chocolate Intake Buffers Stress Reactivity in HumansJournal of the American College of Cardiology. 63 (21), 2297-2299.

13 Nieman, D., Gillitt, N., Sha, W., Meaney, M., John, C., Pappan, K. & Kinchen, J.. (2015). Metabolomics-Based Analysis of Banana and Pear Ingestion on Exercise Performance and Recovery. Journal of Proteome Research. 14 (12), 5367-5377.

14 Steptoe, A., Gibson, E., Vuononvirta, R., Williams, E., Hamer, M., Rycroft, J., Erusalimsky, J. & Wardle, J. (2007). The effects of tea on psychophysiological stress responsivity and post-stress recovery: a randomised double-blind trialPsychopharmacology. 190 (1), 81-89.

15 Schmidt, K., Cowen, P., Harmer, C., Tzortzis, G., Errington, S. & Burnet, P. (2015). Prebiotic intake reduces the waking cortisol response and alters emotional bias in healthy volunteersPsychopharmacology. 232 (10), 1793-1810.

16 Niu, S-F., Chung, M-H., Chen, C-H., Hegney, D., O’Brien, A. & Chou, K-R. (2011). The effect of shift rotation on employee cortisol profile, sleep quality, fatigue, and attention level: a systematic review. Journal of Nursing Research. 19 (1), 68-81.

17 Irish, L., Kline, C., Gunn, H., Buysse, D. & Hall, M. (2015). The Role of Sleep Hygiene in Promoting Public Health: A Review of Empirical EvidenceSleep Medicine Review. 22 (..), 23-36.

18 Cho, Y., Ryu, S-H., Lee, B., Kim, K., Lee, E. & Choi, J. (2015). Effects of artificial light at night on human health: A literature review of observational and experimental studies applied to exposure assessmentChronobiology International. 32 (9), 1294-1310.

19 Hill, E., Zack, E., Battaglini, C., Viru, M. & Hacknet, A. (2008). Exercise and circulating cortisol levels: the intensity threshold effectJournal of Endocrinology Investigation. 31 (7), 587-591.

20 Hackney, A. & Viru, A. (1999). Twenty-four-hour cortisol response to multiple daily exercise sessions of moderate and high intensityClinical Physiology. 19 (2), 178-182.

21 Perciavalle, V., Blandini, M., Fecarotta, P., Buscemi, A., Di Corrado, D., Bertolo, L., Fichera, F. & Coco, M. (2017). The role of deep breathing on stressNeurological Sciences. 38 (3), 451-458.

22 Le Roux, F., Bouic, P. & Bester, M. (2007). The effect of Bach’s magnificat on emotions, immune, and endocrine parameters during physiotherapy treatment of patients with infectious lung conditions. Journal of Music Therapy. 44 (2), 156-168.

23 Steptoe, A., Dockray, S. & Wardle, J. (2009). Positive affect and psychobiological processes relevant to healthJournal of Personality. 77 (6), 1747-1776

24 Krause-Parello, C., Tychowski, J., Gonzalez, A. & Boyd, Z. (2012). Human-canine interaction: exploring stress indicator response patterns of salivary cortisol and immunoglobulin AResearch and Theory for Nursing Practice. 26 (1), 25-40.

25 Vlachopoulos, C., Xaplanteris, P., Alexopoulos, N., Aznaouridis, K., Vasiliadou, C., Baou, K., Stefanadi, E. & Stefanadis, C. (2009). Divergent effects of laughter and mental stress on arterial stiffness and central hemodynamicsPsychosomatic Medicine. 71 (49), 446-453.

26 Barbadoro, P., Annino, I., Ponzio, E., Romanelli, R., M’Derrico, M., Prospero, E. & Minelli, A. (2013). Fish oil supplementation reduces cortisol basal levels and perceived stress: a randomized, placebo-controlled trial in abstinent alcoholics. Molecular Nutrition & Food Research. 57 (6), 1110-1114.

27 Chandraskhar, K., Kapoor, J. & Anishetty, S. (2012). A Prospective, Randomized Double-Blind, Placebo-Controlled Study of Safety and Efficacy of a High-Concentration Full-Spectrum Extract of Ashwagandha Root in Reducing Stress and Anxiety in AdultsIndian Journal of Psychological Medicine. 34 (3), 255-262.

28 NHS, 2012, The Stress Reaction, Last accessed 26/04/2021

29 Ambrogio, A., Giraldi, F. & Cavagnini. (2008). Drugs and HPA axisPituitary. 11, 219-229

30 Mental Health Foundation. (2018). Stressed Nation. Last accessed 05/05/2021

cortisol test for stress management - elevateMe

Written by Louise Taylor

After completing Clinical Technology at the University of Bradford, I am venturing into the NHS as a General Medical Engineer.


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