Cortisol Saliva Stress Test, from our experts to you.Dr Sam Rodgers MBBS, MRCGP
Chief Medical Officermeet our doctors
What is cortisol?
Cortisol is a steroid hormone, produced by the adrenal glands. It is vital for survival given its role in various functions such as immunity, regulating blood pressure and releasing insulin for blood sugar maintenance. Cortisol has been termed the 'stress' hormone because it is secreted in higher quantities during the body's 'fight or flight' response to stress, and is responsible for several stress-related changes in the body.
When should I take my cortisol saliva sample?
Cortisol levels naturally fluctuate throughout the day but sometimes your levels might higher or lower than normal causing symptoms such as difficulty waking in the morning or going to sleep at night and craving sugary snacks especially late in the day. Cortisol levels should be highest just after waking in the morning and lowest at bedtime. This test establishes the levels of cortisol in the saliva at 4 different points in the day. Samples are taken after waking, 12 noon, 4pm and before going to sleep.
What can I learn from the cortisol saliva test?
This test can tell you if you are experiencing excessive stress during the day and whether you need to be adjusting your lifestyle to introduce more relaxation and modify other lifestyle factors such as your sleep and your diet. This test can help identify Cushing's syndrome, which is caused by too much cortisol, or Addison's disease, which is caused by damage to the adrenal glands and is associated with too little cortisol. It is also used by some practitioners in the diagnosis of adrenal fatigue, a condition where elevated levels of stress are thought to impair adrenal function. Please note that the lower detection limit for this test is 1.5 nmol/L.
How to prepare for your test?
Do not eat or drink for 30 minutes before your test. Do not brush your teeth for 30 minutes before your test. Your result could be affected by corticosteroid medication (e.g. prednisolone). Ask your doctor whether you should stop before testing. HRT and the contraceptive pill can affect the results of this test, taking the test during a break from these will give more accurate results. Do not take biotin supplements for 2 days prior to this test. If you are taking prescribed biotin you should discuss this with your doctor.