What cortisol does
Cortisol is made by the adrenal glands under the control of the pituitary. It helps the body handle stress, illness and the daily rhythm of waking and sleeping.
Too much: Cushing syndrome
The most common cause is long-term steroid medicine, including tablets, injections and strong creams. Less often a pituitary or adrenal tumour is responsible. Signs include:
- Weight gain around the trunk, a rounder face and a fat pad on the upper back
- Wide purple stretch marks, thin skin and easy bruising
- Weakness in the thigh and shoulder muscles
- High blood pressure, high blood sugar and weak bones
- Irregular periods and mood changes
Too little: adrenal insufficiency
- Tiredness, weight loss and poor appetite
- Nausea, dizziness on standing and low blood pressure
- Salt craving and darkening of the skin (in adrenal disease)
- Low blood sugar
Severe vomiting, weakness and low blood pressure can be an adrenal crisis, a medical emergency. Call 108 or go to the nearest emergency department.
Testing
No single test is enough. For excess cortisol, tests include an overnight dexamethasone suppression test, late-night saliva cortisol and 24-hour urine cortisol. For deficiency, a morning cortisol and a stimulation test are used. Many medicines, including steroid inhalers, creams and contraceptive pills, can affect results, so tell your doctor about all of them.
An important warning
Never stop steroid medicine suddenly after more than a few weeks of use. The body may not make enough cortisol on its own. Reduce it only as advised.
When to see a specialist
Consider an endocrinology opinion if you have these features, an adrenal lump found on a scan, or are on long-term steroids and feel unwell.
This guide is general information and is not a substitute for a consultation.