Cortisol Blood Test
CortisolWeight gain

Cortisol Blood Test

Cortisol Blood Test

November 23, 2020

Cortisol Blood Test

Cortisol Blood Test

Cortisol is a bit of a jack-of-all-trades hormone – it’s involved in countless functions and processes in your body and it’s vital to keeping you a healthy, functioning human.

But it’s also produced when you come under stress and your body hits its internal ‘panic button’. When this happens, your body starts pumping cortisol into your blood.

What is a cortisol blood test?

A cortisol blood test tells us the levels of cortisol in your blood. The test is like any other routine blood test and involves a sample of blood being taken from your arm. This is then analysed by our team of specialists to find out more information about your cortisol levels.

What is cortisol?

Cortisol is an important steroid hormone in your body that’s involved in lots of different bodily functions. Some of these are:

  • Helping your body control your blood sugar and blood pressure

  • Balancing salt & water levels

  • Helping to coordinate your sleep cycles

  • Influencing memory formation

  • Regulating insulin to manage blood sugar

Your cortisol levels are highest in the morning and decrease gradually throughout the day. Cortisol is essential for healthy responses and functions in the body, but elevated levels can have serious health effects.

Cortisol is also involved in your fight-or-flight response. When you come under danger or stress, your body pumps cortisol and other hormones into your body to help you respond to the stress. This comes from the early days of humanity, when this response would let us fight off or escape life threatening situations.

We don’t need to escape too many woolly mammoths these days but, unfortunately, your body will still trigger a fight-or-flight response when confronted with some of the more mundane stresses of modern-day life.

Why take a cortisol blood test?

Unhealthy cortisol levels can cause a litany of health problems, from mild to severe. By knowing your cortisol levels and identifying if you have high or low cortisol, you can evaluate whether your cortisol levels and your lifestyle are causing your health problems.

High cortisol levels

We know cortisol is vital to you functioning as a healthy human, so what’s the problem?

The problems happen when you come under stress regularly, and your body starts hitting that internal panic button too much. If you have consistently high cortisol levels, you can start suffering from lots of different side effects.

Signs and symptoms include:

  • Weight gain

  • Weakness in the muscles

  • High blood pressure

  • Fatigue

  • Anxiety

  • Depression

  • Thinning hair

  • Thinning of bones leading to osteoporosis

  • Upsetting sleep

  • Erectile dysfunction and lowered sex drive

  • Women can experience irregular periods as well as high levels of oestrogen

In rare cases, high cortisol levels can be a sign of Cushing’s Syndrome. This is a spectrum of disorders which cause an increase of cortisol. The most common of these is Cushing’s Disease which is caused by a tumour on the pituitary gland.

High levels of cortisol have also been linked to developing other illnesses, such as diabetes and cardiovascular problems, as well as causing issues with the digestive and reproductive systems.

Your lifestyle and other causes of high levels of cortisol

Your lifestyle choices and surroundings have a big effect on your cortisol levels. Levels can fluctuate as we experience stressful situations - anything from being late for a meeting or trying to hit tight deadlines, to personal relationships and family life.

These are some of the most common causes of unhealthy cortisol levels:

  • Working a high-pressure job

  • Stress in your personal life

  • Eating low quality food

  • Working night shifts or alternating shift patterns

  • Changes in the time you wake up

  • The way you wake up

  • Drinking a lot of coffee

  • Smoking

If you take corticosteroids, you can experience side effects similar to those of high cortisol levels - this is because they are cortisol-like medications that have the same effects as cortisol. While taking corticosteroids regularly over a prolonged period of time (i.e. chronic treatment) can actually suppress our own production of corticosteroids.

High levels of oestrogen are known to cause high cortisol levels in women. This can occur during pregnancy, or if you’re undergoing oestrogen therapy.

Overactive pituitary and adrenal glands can also lead to raised cortisol levels.

Low cortisol levels

While high levels of cortisol can cause health problems, the same is true for low cortisol levels. Low cortisol levels are usually caused by damage to the pituitary or adrenal gland glands. This damage is typically due to a condition called Addison’s disease. Signs and symptoms can include:

  • Fatigue

  • Dizziness

  • Weight loss

  • Feeling weak

  • Mood swings or feeling irritable

  • Body hair loss

  • Feeling sick and vomiting


Pivonello, Rosario et al. “Cushing's disease: the burden of illness.” Endocrine vol. 56,1 (2017): 10-18. doi:10.1007/s12020-016-0984-8

Pouwer, Frans et al. “Does emotional stress cause type 2 diabetes mellitus? A review from the European Depression in Diabetes (EDID) Research Consortium.” Discovery medicinevol. 9,45 (2010): 112-8.

Betterle, C et al. “Epidemiology, pathogenesis, and diagnosis of Addison's disease in adults.” Journal of endocrinological investigation vol. 42,12 (2019): 1407-1433. doi:10.1007/s40618-019-01079-6

Williams, Emily et al. “The impact of time of waking and concurrent subjective stress on the cortisol response to awakening.” Psychoneuroendocrinology vol. 30,2 (2005): 139-48. doi:10.1016/j.psyneuen.2004.06.006

A.H.Garge, R. Persson, Effects of lifestyle factors on concentrations of salivary cortisol in healthy individuals, Scandanavian Journal of Clinical Laboratory Investigation 69:2,242-250, DOI:

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