Cortisol is a hormone released by the adrenal glands, and its level rises and falls through the day, including in response to stress. Raised cortisol can increase appetite and is associated with fat stored around the abdomen. In most people with weight gain, cortisol levels are normal. Normal stress-related fluctuation is not the same as the persistently high cortisol of Cushing syndrome, a rare condition that an endocrinologist diagnoses with dedicated tests.
- Cortisol affects appetite, blood sugar and how the body stores fat, particularly around the abdomen. Cortisol levels also naturally fluctuate throughout the day.
- A 2018 review in Current Obesity Reports found that increased long-term cortisol levels, measured in scalp hair, are strongly related to abdominal obesity, although not all patients with obesity have elevated cortisol.
- The UAE National Health Survey found that 67.9% of adults aged 18 to 69 had overweight or obesity, so weight gain alone is not an indication to test cortisol.
- Most adults are advised to aim for around seven to nine hours of sleep a night, and short sleep can raise ghrelin and cortisol and lower leptin.
- Persistently high cortisol with signs such as a rounded face, a fat pad at the back of the neck and purple stretch marks can indicate Cushing syndrome, which Cleveland Clinic describes as rare.
- Endocrinologists test cortisol with a 24-hour urine collection, a late-night saliva sample or a dexamethasone suppression test, because a single blood level varies with the time of day.
- No supplement is established as a treatment for high cortisol, and a persistently raised level needs investigating by a doctor.
Cortisol has become a popular explanation for weight gain, and many supplements are now marketed to lower it.
What does cortisol do in the body?
Cortisol is a steroid hormone made by the adrenal glands, two small glands that sit above the kidneys. The brain controls its release through the hypothalamic-pituitary-adrenal axis, and it follows a daily rhythm: highest in the early morning, falling through the day and lowest around midnight. The axis releases more cortisol in response to physical or psychological stress.
Cortisol raises blood sugar by prompting the liver to release glucose, helps regulate blood pressure, reduces inflammation and influences appetite. Those effects are normal and necessary in the short term. The effects on weight relate to cortisol that stays raised for long periods.
How does raised cortisol affect weight and where fat is stored?
Raised cortisol can increase appetite, particularly for energy-dense food, and it can promote fat storage around the abdominal organs, the fat known as visceral fat. A 2018 review in Current Obesity Reports found that increased long-term cortisol levels, measured in scalp hair, are strongly related to abdominal obesity, and that not all patients with obesity have elevated cortisol levels. The authors suggest that differences in how sensitive people are to cortisol may explain why stress affects weight in some people more than others.
Cortisol also raises blood sugar, and prolonged elevation is associated with insulin resistance, which can make weight management more difficult. Visceral fat is itself associated with insulin resistance, so the two can reinforce each other. A body composition analysis can estimate visceral fat and provide a visceral fat rating that can be tracked over time.
Is cortisol belly a real thing?
Long-term cortisol exposure is associated with abdominal fat, which is what the term describes. The popular claim that a stressed person’s abdominal weight is caused by cortisol, and will resolve once cortisol is lowered, is not supported by evidence. For most patients, abdominal fat reflects overall energy balance, sleep, activity, genetics and age, with cortisol as one contributing factor.
Abdominal fat is therefore a reason to assess metabolic risk, with waist circumference, blood pressure, blood sugar and lipids. Measuring waist circumference or body composition can be useful when there are signs of increased metabolic risk, such as a raised waist measurement or abnormal glucose or lipid results.
Which symptoms suggest cortisol is worth testing?
Weight gain is common and Cushing syndrome is rare. The UAE National Health Survey 2017 to 2018, published by the Ministry of Health and Prevention, found that 67.9% of adults aged 18 to 69 had overweight or obesity, so stress-related weight gain on its own is not an indication to test cortisol. The symptoms that make testing worth discussing with a doctor are the ones associated with persistently high cortisol:
- Weight gain concentrated on the trunk with thinner arms and legs
- A rounded face or a fat pad between the shoulders
- Purple or pink stretch marks on the abdomen
- Easy bruising and thin skin
- Muscle weakness, particularly in the thighs
- High blood pressure or high blood sugar that is new or hard to control
- Irregular periods, low mood or poor sleep alongside the above
If you have several of these signs together, we recommend an assessment by an endocrinologist. If you have abdominal weight gain alone, without these signs, a metabolic assessment is more likely to help than a cortisol test.
When is raised cortisol a medical condition?
Cushing syndrome
Cushing syndrome is the condition in which the body is exposed to excess cortisol over a long period. Cleveland Clinic describes it as rare, most often caused by long-term steroid medication and less often by a tumour on the pituitary or adrenal gland that drives cortisol production. The signs it lists include a rounded face, weight gain, a fat pad at the back of the neck, purple or pink stretch marks, easy bruising, fatigue and muscle weakness.
Cushing syndrome is treatable, and the treatment depends on the cause. Our endocrinologists assess and manage adrenal and pituitary conditions, and our page on hormonal imbalance and weight explains the wider group of endocrine causes of weight gain.
How is cortisol tested?
Because cortisol varies through the day, a single blood level taken at a random time is of limited value. Cleveland Clinic lists three tests for diagnosing Cushing syndrome: a 24-hour urine collection for free cortisol, a late-night saliva sample, and a dexamethasone suppression test. In the suppression test, the patient takes a small dose of a steroid medication and the laboratory measures cortisol the next morning to see whether the body suppresses its own production.
Reference ranges differ by laboratory, by assay and by the time of day. Your endocrinologist will interpret a result against the range on the report and in the context of your symptoms. An abnormal screening result is followed by further testing to confirm it and to find the cause. Our blood tests page explains what the assessment panel covers. Your endocrinologist will arrange cortisol testing where your symptoms justify it.
Do cortisol supplements work?
No supplement is established as a treatment for high cortisol. Products marketed as cortisol blockers or adrenal support often contain herbal extracts. The claim that they reduce abdominal fat by lowering cortisol is not supported by evidence. Supplements are regulated differently from medications. They do not go through the same testing for effectiveness, and their ingredients are not checked as strictly.
If cortisol is raised, the cause needs investigating, because the treatment for Cushing syndrome depends on it. If cortisol is normal, there is no raised level to treat. Some supplements can also interact with prescribed medication.
What lowers cortisol?
Sleep
Most adults are advised to aim for around seven to nine hours of sleep a night. Short sleep can raise ghrelin, the hormone that increases appetite, and cortisol, while lowering leptin, the hormone that signals fullness. Sleep is therefore part of a weight management plan, and it is one of the areas Endocare’s lifestyle coaches work on with patients.
Stress and recovery
Sustained psychological stress keeps the hypothalamic-pituitary-adrenal axis active. Regular recovery, such as breathing exercises, prayer, meditation or protected time off, can lower the stress response. The evidence for these approaches relates mainly to wellbeing and stress. Where low mood or anxiety is present, treating it can be part of the weight management plan.
Movement
Regular moderate activity can improve sleep, mood and insulin sensitivity, each of which is associated with better weight management. Very intense training without recovery can raise cortisol in the short term. A programme for a patient under stress therefore builds up gradually. Our article on strength training while losing weight covers how to start.
Frequently asked questions
How do I know if my weight gain is caused by cortisol?
You cannot tell from weight alone. The signs that point towards a cortisol problem are weight on the trunk with thin limbs, a rounded face, purple stretch marks, easy bruising and muscle weakness together. Without those signs, abdominal weight gain is more likely to reflect energy balance, sleep and metabolic health, and an endocrinologist can assess which applies to you.
What are the symptoms of high cortisol?
Signs of persistently high cortisol can include weight gain around the abdomen, a rounded face and a fat pad between the shoulders. Other signs include wide purple stretch marks, easy bruising, muscle weakness and high blood pressure or blood sugar. Several of these together justify testing.
Is cortisol belly a real thing?
The association between long-term cortisol exposure and abdominal fat is real and is described in the research literature. The idea that abdominal fat is caused by cortisol and will resolve once cortisol is lowered is not supported for most people.
How is cortisol tested?
Your endocrinologist can test cortisol with a 24-hour urine collection, a late-night saliva sample or a dexamethasone suppression test, because a single blood level varies with the time of day. Your endocrinologist will read the results against the laboratory’s own reference range and your symptoms.
Do cortisol supplements work?
No supplement is established as a treatment for high cortisol. A raised level needs investigating to find the cause, and a normal level does not need lowering.
Can stress alone cause weight gain?
Stress can contribute, through appetite, sleep, cortisol and the eating patterns that follow a difficult period, and it is rarely the only cause. Our lifestyle coaches address sleep, recovery and activity alongside food.
If you have the signs described above, or weight that has not responded to a consistent plan, the first step is a consultation. Your endocrinologist will review your symptoms, your blood tests and your body composition analysis, and will arrange cortisol testing where the picture justifies it.
You can book a consultation at our clinics in Dubai and Abu Dhabi.
