1.    Adam, E. K. et al. Diurnal cortisol slopes and mental and physical health outcomes: A systematic review and meta-analysis. Psychoneuroendocrinology 83, 25–41 (2017).
2.    Wright, K. P. et al. Influence of sleep deprivation and circadian misalignment on cortisol, inflammatory markers, and cytokine balance. Brain Behav Immun 47, 24–34 (2015).
3.    Schmidt, S. C. E., Gnam, J.-P., Kopf, M., Rathgeber, T. & Woll, A. The Influence of Cortisol, Flow, and Anxiety on Performance in E-Sports: A Field Study. Biomed Res Int 2020, 9651245 (2020).
4.    Boolani, A. et al. Trends in Analysis of Cortisol and Its Derivatives. Adv Exp Med Biol 1140, 649–664 (2019).
5.    Ceccato, F. & Boscaro, M. Cushing’s Syndrome: Screening and Diagnosis. High Blood Press Cardiovasc Prev 23, 209–215 (2016).
6.    Neumann, A.-M., Schmidt, C. X., Brockmann, R. M. & Oster, H. Circadian regulation of endocrine systems. Auton Neurosci 216, 1–8 (2019).
7.    Cortisol (Blood) - Health Encyclopedia - University of Rochester Medical Center. https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=cortisol_serum.
8.    El-Farhan, N., Rees, D. A. & Evans, C. Measuring cortisol in serum, urine and saliva - are our assays good enough? Ann Clin Biochem 54, 308–322 (2017).
9.    Dimolareva, M. et al. Measuring Cortisol in the Classroom with School-Aged Children—A Systematic Review and Recommendations. Int J Environ Res Public Health 15, 1025 (2018).
10.    Kalman, B. A. & Grahn, R. E. Measuring Salivary Cortisol in the Behavioral Neuroscience Laboratory. J Undergrad Neurosci Educ 2, A41–A49 (2004).
11.    Cai, R. et al. Association between thyroid function and serum cortisol in cortisol-producing adenoma patients. Endocrine 69, 196–203 (2020).
12.    Dhillo, W. S. et al. Cortisol-binding globulin is important in the interpretation of dynamic tests of the hypothalamic--pituitary--adrenal axis. Eur J Endocrinol 146, 231–235 (2002).
13.    Plechner, A. J. Cortisol abnormality as a cause of elevated estrogen and immune destabilization: insights for human medicine from a veterinary perspective. Med Hypotheses 62, 575–581 (2004).
14.    Stress Cortisol Home Saliva Test (6) – UK Health Screening. https://ukhealthscreening.com/product/stress-cortisol-home-saliva-test-6/.
15.    Speiser, P. W. et al. Congenital adrenal hyperplasia due to steroid 21-hydroxylase deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab 95, 4133–4160 (2010).
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17.    Nieman, L. K. et al. The diagnosis of Cushing’s syndrome: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab 93, 1526–1540 (2008).
18.    Sakihara, S. et al. Evaluation of plasma, salivary, and urinary cortisol levels for diagnosis of Cushing’s syndrome. Endocr J 57, 331–337 (2010).
19.    Cortisol Levels during the Menopausal Transition and Early Postmenopause: Observations from the Seattle Midlife Women’s Health Study. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2749064/.
20.    Rathbun, K. M., Nguyen, M. & Singhal, M. Addisonian Crisis. in StatPearls (StatPearls Publishing, 2021).
 

Testing your cortisol levels at home is possible with the aid of a cortisol testing kit. This is often done when your doctor wants you to take blood samples at several time points throughout the day to have a better idea of how your body responds to stress. If you were diagnosed with Cushing syndrome or Addison’s disease, then you often might be required to test your cortisol levels with a home test on a regular basis.

In order to prepare for a cortisol home test, your doctor might also ask you to take hormone containing drugs such as those containing oestrogen (contraception pills for example), androgens, glucocorticoids, and phenytoin [12,13].

As stress can increase your cortisol levels, it is advised to rest before taking the test [3]. You can order a cortisol home test kit online from Vitall and you will receive the test quickly in the post. All you have to do is simply prick your finger to draw blood, fill a small tube and return the sample in the envelope provided. Your blood sample will be analysed and the cortisol test results delivered to you securely online, usually within 24 hours [8,9,14]. 
 

Normal cortisol levels taken from a blood sample in the morning (6 - 10AM) range from  133 - 537 nmol/l, and at midnight are  less than 150 nmol/L.

Some drugs can impact cortisol levels, for example codeine and alprazolam can decrease your cortisol levels while sertraline, methylphenidate, thyroid and growth hormones can increase your cortisol levels. 

Your cortisol home test results will clearly indicate the normal range and how your cortisol levels compare.
 

If the underlying cause of high cortisol levels is Cushing syndrome then symptoms can include:

• weight gain, especially in the face and torso
• flushed skin and a round face
• changes to the skin such as bruising or stretch marks
• increased bood pressure
• fatigue and weakness
• mood swings [16]

Taking a cortisol test at home can give you a clearer understanding of your cortisol levels and help you and your doctor identify the underlying issue.

Typical symptoms of low cortisol levels are decreased appetite and weight loss, fatigue, low blood pressure, muscle weakness and joint pain, loss of body hair, an irregular menstrual cycle, abdominal pain, irritability, and hyperpigmentation of the skin [16]. 

By using a cortisol home test kit, accurate cortisol levels can be determined, allowing you and your doctor to better understand the cause of your symptoms.

High cortisol levels could be a sign of many different conditions. First of all, high cortisol levels upon waking up, or even normal cortisol levels which do not decrease towards the end of the day, could suggest Cushing syndrome. It is important to rule out any contributing factors to these high cortisol levels, such as stress or taking high doses of glucocorticoid medications (prednisone for instance).

For this, an overnight dexamethasone suppression test is carried out as dexamethasone suppresses ACTH production from the pituitary gland which in turn decreases cortisol production. If you are experiencing stress or you are taking glucocorticoid medication, your cortisol levels should decrease after the dexamethasone suppression test [5,17].

With Cushing syndrome, your cortisol levels will remain unchanged, you might have an abnormal production of ACTH from the pituitary gland due to an overactive pituitary gland (hyperpituitarism) or an adrenal gland tumour, or in more severe cases a tumour of the pituitary gland. Your doctor might ask you to take your cortisol home test late at night, as it is the best way to determine if you have Cushing syndrome [18].

Bear in mind that if you are pregnant or if you are having oestrogen therapy, your cortisol levels will be generally higher [13,19].

Low cortisol levels resulting from your cortisol home test could mean that you have a problem either with your pituitary gland being underactive (hypopituitarism) and not producing enough ACTH, or your adrenal glands not producing enough cortisol (Addison’s disease) [16].

An ACTH stimulation can be done to see if the problem is based in the pituitary or adrenal glands. If you respond to an ACTH stimulation test, your pituitary gland is most likely the issue. It is important to note that Addison’s disease is extremely rare, so if you present symptoms of Addison’s, your doctor might want to carry out more tests to identify the root problem as it could be caused by something else. For example, people with low cortisol levels that do not respond to ACTH stimulation tests, could have a condition known as congenital adrenal hyperplasia (CAH) [15].

Furthermore, people with hypothyroidism can experience low cortisol levels. You may wish to take a thyroid home test if this is the case [11].

If in the rare event you are diagnosed with Addison’s disease, you might also experience symptoms on a psychological level, such as depression and sleep disturbances. Leaving Addison’s disease untreated can lead to very serious side effects and a state of crisis known as the Addisonian crisis. The typical symptoms of an Addisonian crisis are hallucinations, delirium, and irritability.

If you start to have any of these symptoms, you must contact your doctor. If you experience more severe symptoms such as a high fever, passing out, mental confusion or appearing to be in a state of panic, or you suddenly experience strong pain in the lower back, your abdomen, or your legs, you must immediately go to the emergency department, as an Addisonian crisis can be fatal [16,20]. 
 

A cortisol home test requires either a blood, urine, or saliva sample to measure your levels of cortisol. Blood samples are the most common type of home cortisol test in the UK as they are the easiest to obtain.

Collecting your blood sample for a cortisol home test is carried out in the morning, usually between 7 to 9 am, where cortisol levels are at their peak. As your cortisol levels vary throughout the day, the blood test may be carried out several times throughout the day to get a better picture of your average cortisol production.

A cortisol blood test measures protein-bound cortisol and free cortisol, which helps indicate a wide range of conditions, such as Cushing syndrome where you have too much cortisol, or Addison’s disease where you don’t have enough cortisol.

If your cortisol home test shows that cortisol levels are not within the normal range, your doctor will usually carry out more tests to find the root of the problem [5,7,8,9]. 

Cortisol, also known as hydrocortisone, is a steroid hormone that is produced from cholesterol and secreted from the glands situated right on top of your kidneys, also known as the adrenal glands. It plays an important role in your body’s metabolism of proteins, lipids and carbohydrates, immune responses and most importantly your stress responses.

Cortisol is often referred to as the “stress hormone”, and is released when you are stressed, and this can in turn affect many of your bodily functions [1,2,3]. Whenever you experience new symptoms, it is always important to take into account whether you are stressed or not, because we tend to neglect the fact that many health issues can be partly due to stress, from indigestion, stomach cramps, headaches, or even high cholesterol and more serious heart issues.

There are 3 regions of your body which communicate together and affect your levels of cortisol: the hypothalamus, which is a small region located in your brain, the pituitary gland which is located under the hypothalamus, and the adrenal glands.

These three regions working together are known as the hypothalamic-pituitary-adrenal axis. When your blood cortisol levels are low, the hypothalamus releases a hormone called the corticotrophin-releasing hormone (CRH), which in turn causes the pituitary gland to secrete the adrenocorticotropic hormone (ACTH) into the blood, causing the adrenal glands to detect this change and stimulate the secretion of cortisol. Your cortisol levels will then increase, and the adrenal glands will stop the production of CRH from the hypothalamus, to lower your cortisol levels.

When you encounter a stressful situation, say the fire alarm goes off, the hypothalamus will trigger the release of hormones and ultimately adrenaline and cortisol. These hormones can temporarily lead to an increased heart rate, a higher blood pressure, and an increase in energy production. You can also experience sweating, muscle tension, heavy breathing, dry mouth, and even the need to urinate. These stress responses are known as the “fight-or-flight” response [4,5].

Your cortisol levels vary throughout the day, and follow a diurnal variation rhythm, meaning you have the highest levels of cortisol when you wake up in the morning, and it gradually decreases throughout the day to its lowest levels around midnight. This is why sample collection for a cortisol home test should be done first thing in the morning when you wake up. Alternatively, using a cortisol test kit at midnight as directed by your doctor can also be used to help identify Cushing syndrome.

Sleep is very important because if you have an abnormal sleeping schedule, work late nights, or sleep too much, your cortisol levels will be affected, in turn affecting your body’s metabolism. Cortisol levels can also be disrupted if you have a condition that affects cortisol production [1,2,6].
 

If you are experiencing symptoms that suggest high levels of cortisol such as weight gain, fragile skin, high blood pressure, high blood sugar, and muscle weakness, you may wish to take a cortisol home test. For women, excessive facial hair or irregular menstrual periods could be a sign of high cortisol levels as well.

If you are experiencing symptoms characteristic of low cortisol levels such as weight loss, fatigue, low blood pressure, or dark patches of skin can also be asked to take a cortisol test [2,15,16].

Patients diagnosed with Addison’s disease or Cushing syndrome are usually requested by their doctor to measure their cortisol levels on a frequent basis. 

Unless directed otherwise, samples for your cortisol home test kit should be collected in the morning, before 9AM, when cortisol levels are at their highest.

There are three different ways to test your cortisol levels: blood, urine, and saliva cortisol tests kits.

Urine and saliva tests measure free cortisol levels while blood cortisol home test kits measure both protein-bound and free cortisol.

This means that a home cortisol blood test can give you a good picture of adrenal gland function and their capacity for total cortisol synthesis and its release into the bloodstream.[10,11]