Cortisol is one of the hormones that plays a key role in maintaining the body's internal balance. When its levels are outside normal limits, changes occur that can affect numerous vital processes.

Are you constantly experiencing anxiety, fatigue that doesn't go away after sleep, or even changes in your menstrual cycle? Behind these signals could be a cortisol imbalance. Discover what the limits are considered normal, how high or low cortisol affects you in the long term, and what treatment options are available.

What is cortisol?

Cortisol is a glucocorticoid, a steroid hormone produced by the adrenal glands, in the zona fasciculata, and released into the bloodstream. Cortisol secretion is controlled by the hypothalamic-pituitary-adrenal axis (HPA axis), and adrenocorticotropic hormone (ACTH) directly stimulates production.

Although it's nicknamed the "stress hormone," cortisol mediates processes that affect almost every organ and tissue in your body. It influences carbohydrate metabolism, the immune system, blood pressure, the sleep-wake cycle, and, as the name suggests, the body's response to stressful situations.

How cortisol is produced and regulated – the cortisol regulatory mechanism

Cortisol production is regulated by the hypothalamic-pituitary-adrenal axis, a complex hormonal system that responds rapidly to the body's needs.

The process begins in the hypothalamus, which secretes corticotropin-releasing hormone (CRH). This stimulates the release of adrenocorticotropic hormone (ACTH) from the anterior pituitary gland, and ACTH acts on the adrenal glands to cause the secretion of cortisol.

Once cortisol levels rise sufficiently, it exerts a negative feedback mechanism on the hypothalamus and pituitary to reduce the production of CRH and ACTH.

This is how the body's hormonal self-regulation process normally works. However, when this system goes out of control, imbalances such as increased cortisol or high cortisol can occur.

Circadian rhythm of cortisol and daily variations of cortisol

Cortisol levels vary throughout the day, generally being higher in the morning and lower in the evening. This cycle is known as the circadian rhythm and is a well-defined one, aligned with the sleep-wake cycle.

Values reach their maximum in the morning, usually between 6 and 8 a.m., in order to prepare the body for activity and energy consumption, and then gradually decrease until the evening to allow a state of relaxation to set in and facilitate sleep.

This natural rhythm can be altered by sleep disorders, chaotic schedules, or prolonged exposure to stress.

Morning cortisol vs evening cortisol – interpreting cortisol values

Cortisol levels are physiologically higher in the morning, when the body is preparing for the energy expenditure of the day. In the evening, values should be significantly lower.

The absence of this difference is associated with abnormal cortisol levels. If levels remain elevated even during the evening, they may suggest excess cortisol secretion (hypercortisolism), while low levels in the morning may indicate possible adrenal insufficiency.

Therefore, cortisol evaluation is always done in a clinical context and sometimes requires additional tests for a correct diagnosis.

Cortisol and sleep – the connection between cortisol and sleep

Cortisol directly influences the sleep-wake cycle and the body's alertness level.

Normally, the decrease in production in the second half of the day contributes to the induction of a state of drowsiness. If cortisol levels remain elevated in the evening, they can cause insomnia and open a kind of vicious cycle. Lack of sleep or poor quality sleep can cause cortisol levels to increase the next day, perpetuating this cycle.

In the long term, cortisol imbalance affects sleep quality as well as metabolism, immunity, and emotional balance.

The role of cortisol in the body – the main functions of cortisol

Although cortisol is most often associated with stress, it is involved in processes that support the internal balance of the entire body:

• It stimulates gluconeogenesis and increases blood sugar levels, coordinating how the body uses glucose to produce energy.
• It is involved in the metabolism of proteins and fats.
• It has anti-inflammatory and immunosuppressive effects, which is why synthetic derivatives of cortisol are frequently used to reduce inflammation.
• It contributes to the regulation of blood pressure.
• It plays an essential role in the "fight or flight" response, preparing the body to react quickly to danger.
• It influences memory and cognitive function, acting on certain brain regions involved in information processing and emotion regulation.

Cortisol and stress – how stress influences cortisol levels

Stress is the main factor that causes cortisol fluctuations. In situations of acute stress, cortisol levels temporarily increase to help the body adapt quickly, after which it returns to normal.

Problems arise when stress becomes chronic and cortisol remains consistently elevated. This can lead to HPA axis dysregulation, and long-term excess cortisol can affect metabolic and mental health.

Cortisol and abdominal weight gain

Research has shown that there are more cortisol receptors in visceral fat cells than in the rest of the body, making them more sensitive to the hormone's action. Thus, increased cortisol levels may promote fat deposition in the abdominal area.

Of course, the mere presence of elevated cortisol levels does not automatically cause the accumulation of visceral fat. A balanced diet and an active lifestyle remain the basis for an optimal body weight.

But another effect of increased cortisol is an increase in appetite, especially for foods high in sugar or fat, and therefore high in calories. The more frequently these foods are consumed, the greater the likelihood of a caloric surplus, the greater the risk of weight gain and the accumulation of visceral fat.

Unlike subcutaneous fat, which is visible on the thighs or hips, for example, visceral fat poses a number of serious health threats. It is metabolically active and constantly releases cytokines (inflammatory substances) into the portal vein that carries blood to the liver, which can increase the risk of cardiovascular disease, insulin resistance, diabetes, and metabolic syndrome.

Cortisol and sleep disorders

High cortisol levels keep the body on high alert. When this state persists into the second half of the day, even into the evening, it can lead to difficulty falling asleep and frequent awakenings during the night, reducing the duration of deep sleep and increasing the risk of insomnia . In turn, sleep deprivation can increase cortisol secretion the next day, continuing a vicious cycle that is difficult to break.

Cortisol and anxiety or depression

Hypercortisolism (excess cortisol) is often associated with anxiety because elevated levels of this hormone keep the body on alert and can increase states of tension, irritability, and hypervigilance. Furthermore, because it also influences neurotransmitters such as serotonin and dopamine, which are involved in mood regulation, cortisol imbalances can contribute to symptoms of depression .

Cortisol and menstruation – the impact of cortisol on the menstrual cycle

Due to its connections to the HPA axis, cortisol is also involved in maintaining the hormonal balance that underlies menstrual health. Long-term elevated levels can disrupt hormones involved in ovulation and menstruation, leading to irregular menstrual cycles .

In other words, excess cortisol can inhibit the secretion of GnRH (gonadotropin-releasing hormone) from the hypothalamus, which leads to a decrease in the release of LH (luteinizing hormone) and FSH (follicle-stimulating hormone) from the pituitary gland. These hormones play an essential role in the maturation of ovarian follicles and the production of ovulation, and their dysregulation can disrupt the menstrual cycle, producing irregular or even absent menstruation .

Because it can induce muscle tension and increase inflammation in the body, high cortisol levels can also amplify pain perception, making menstrual cramps worse. Make sure you use menstrual products with natural, body-friendly ingredients, created without harsh chemicals that can increase the risk of irritation or inflammation during this time.

In the long term, through its negative impact on ovulation and hormonal balance, chronic stress associated with high cortisol levels can have negative effects on fertility .

Normal cortisol values – interpreting cortisol tests

Cortisol levels are normally higher in the morning and decline progressively throughout the day, reaching minimum levels in the evening. Interpretation of cortisol analyses must be made taking into account these physiological fluctuations, the time of collection, and the clinical context of the patient.

Reference ranges may vary slightly depending on the laboratory and the method used. Results are usually expressed in µg/dL or nmol/L, and conversion between units must be done correctly for proper evaluation.

In addition to serum dosing (analysis of the level of cortisol present in the blood), there are other useful investigation methods:

• Salivary cortisol measurement can be useful for assessing circadian rhythm because it allows repeated measurements at different times of the day.
• Measurement of urinary cortisol/24h is particularly indicated when Cushing's syndrome is suspected, as it allows the most accurate assessment of total daily secretion.

Factors such as acute stress, pregnancy, taking oral contraceptives , or physical exertion before the analysis can influence the results, which is why the doctor will always interpret the values in correlation with the symptoms and medical history of each patient.

Elevated cortisol (hypercortisolism) – causes and symptoms of elevated cortisol

Hypercortisolism refers to the condition characterized by excess cortisol production for a prolonged period of time.

It can have both endogenous causes, namely excessive secretion of cortisol in the body caused by the presence of pituitary or adrenal tumors, as well as exogenous causes such as the administration of corticosteroids to treat inflammatory or autoimmune diseases.

Chronic stress is another factor that can contribute to increased cortisol and lead to hypercortisolism.

Visceral fat deposition, purple stretch marks especially on the abdomen, high blood pressure, high blood sugar, muscle weakness, and menstrual disorders are among the manifestations of elevated cortisol.

Elevated cortisol and Cushing's syndrome

Cushing's syndrome is a severe form of hypercortisolism caused by prolonged exposure to high levels of cortisol. It can be caused by tumors of the pituitary gland that secrete excess ACTH hormone, or by adrenal tumors that secrete excess cortisol.

Endocrinological evaluation is required to establish a diagnosis. 24-hour urinary cortisol testing, midnight blood cortisol measurement, and late-night salivary cortisol measurement are the main tests used to confirm Cushing's syndrome.

Increased cortisol due to corticosteroid administration

Prolonged treatment with corticosteroids such as prednisone or dexamethasone for inflammatory or autoimmune diseases can increase the total level of cortisol in the body and cause symptoms similar to Cushing's syndrome, such as hypertension or increased blood sugar.

Since abrupt discontinuation of such treatment can have serious consequences, the dose should be adjusted under medical supervision by a specialist.

Elevated cortisol and pituitary or adrenal tumors

Certain tumors can secrete excess ACTH at the pituitary level or cortisol at the adrenal level, causing major hormonal imbalances and the appearance of typical symptoms of hypercortisolism.

Blood, urine, and saliva tests are needed to measure cortisol levels and identify the cause, and treatment most often consists of surgical removal of the tumor.

Elevated cortisol and chronic stress

Persistent stress keeps the HPA axis active and causes a constantly increased secretion of cortisol, favoring functional hypercortisolism even in the absence of a tumor or other endocrine disease.

It manifests itself through the deposition of abdominal fat, rounding of the face, the appearance of purplish stretch marks, hypertension, muscle weakness, menstrual disorders and, in the long term, osteoporosis and bone fractures.

Low Cortisol (Adrenal Insufficiency) – Causes and Symptoms of Low Cortisol

Medical professionals use the term adrenal insufficiency to refer to abnormally low cortisol levels. It is a severe, chronic condition in which the adrenal glands do not produce the necessary amount of hormones (cortisol and aldosterone).

There are two types of adrenal insufficiency, namely primary and secondary. Primary insufficiency, also called Addison's disease, occurs when the immune system attacks the adrenal glands. Secondary insufficiency is caused by a deficiency of ACTH, caused by hypopituitarism or a pituitary tumor.

Other possible causes of low cortisol levels include suddenly stopping corticosteroid treatment, an infection, or blood loss from the tissues of the adrenal glands.

Low Cortisol and Addison's Disease

Addison's disease is a severe chronic condition that compromises the adrenal glands. It is a common autoimmune disease in which the immune system attacks the adrenal glands and causes their destruction, thereby reducing the production of cortisol and aldosterone.

Low cortisol and secondary adrenal insufficiency

Secondary adrenal insufficiency occurs when the pituitary gland does not secrete enough ACTH, usually due to pituitary disorders or the sudden discontinuation of corticosteroid treatment.

Without the stimulus provided by ACTH, the adrenal glands do not produce cortisol in optimal amounts, and low cortisol manifests itself in severe bone loss, hypotension, hypoglycemia, hyperpigmentation, weight loss, and salt cravings.

A severe complication of secondary adrenal insufficiency is Addisonian crisis, a medical emergency characterized by a sudden drop in cortisol, manifested by severe hypotension, vomiting, intense abdominal pain, dehydration, and loss of consciousness, and requiring immediate treatment.

How to test cortisol – cortisol analysis methods

The amount of cortisol in the body can be measured by several methods, but the most commonly used is a blood test that measures serum cortisol. Generally, the collection is done in the morning, when the level is physiologically higher, but there are situations when the doctor also recommends collecting it during the evening to assess circadian variation.

Other methods of assessing cortisol involve:

• Salivary test: evaluates free cortisol and allows repeated sampling at different times of the day.
• 24-hour urine test: measures total daily secretion and is frequently used in suspected Cushing's syndrome.
• Dexamethasone suppression test: investigates how the body regulates its hormonal secretion, in case of suspected hypercortisolism.
• ACTH stimulation test: evaluates the ability of the adrenal glands to produce cortisol, in case of suspected adrenal insufficiency.

To establish a diagnosis, the endocrinologist will consider both the results of the tests performed, as well as the medical context and symptoms of each patient.

How to reduce cortisol levels naturally – methods for lowering cortisol

If you have Cushing's syndrome, you may need medication or surgery to lower your cortisol levels. However, if your high cortisol is a result of chronic stress, you can help lower it naturally by making lifestyle changes:

• Create a regular sleep schedule of 7-9 hours per night to regulate your circadian rhythm and reduce the risk of excessive cortisol secretion during the day.
• Try to expose yourself to natural light in the morning to help regulate your body clock.
• Regularly engage in moderate-intensity exercise, which can improve the body's response to stress.
• Practice relaxation techniques such as diaphragmatic breathing, meditation, or yoga exercises.
• Reduce caffeine consumption, especially in the second half of the day.
• Try to have a balanced diet, with adequate intake of protein and essential nutrients, to support blood sugar stability.
• Attend psychological therapy sessions if you suffer from chronic stress, to manage your emotions that maintain excessive cortisol secretion.

Treatment for cortisol imbalances – therapeutic options for cortisol

The endocrinologist determines the treatment for cortisol imbalance depending on the cause and severity.

Low cortisol can be treated with hormone replacement therapy with hydrocortisone, which aims to compensate for the deficiency and prevent complications.

For hypercortisolism caused by a tumor, surgery is often the first treatment option. In situations where surgery is not possible, or until surgery can be performed, the doctor may recommend pituitary radiation therapy or treatment with drugs that inhibit cortisol production at the adrenal level.

Regardless of the cause and therapeutic approach, the patient will be monitored endocrinologically in the long term after diagnosis, to adjust treatment and prevent relapses or complications.

Frequently asked questions about cortisol

Cortisol often gets a bad rap because it is associated with high levels of stress. However, this hormone is involved in many vital processes in the body, and not every imbalance can be corrected by better stress management. Sometimes, levels that are too high or too low have hormonal causes and require thorough medical investigation.

If you are still curious about testing methods and the effects of cortisol levels on health, below you will find answers to the most frequently asked questions, which we hope will clarify everything you need to know about cortisol.

What does increased cortisol mean?

Elevated cortisol indicates a level above what is considered normal for this hormone. It can be associated with chronic stress or conditions such as Cushing's syndrome, in which excessive cortisol secretion affects metabolism, sleep, and hormonal balance.

Does stress increase cortisol permanently?

Acute stress causes temporary increases in cortisol, which helps the body adapt to demanding situations. However, chronic stress can keep cortisol levels elevated long-term and have negative effects on overall health.

What are normal cortisol levels in the morning?

Cortisol levels are naturally higher in the morning than in the evening as the body prepares for the day's activities. Exact reference ranges may vary by laboratory.

Does cortisol affect weight?

High cortisol levels can increase appetite and cravings for high-calorie, sugary, and fatty foods, which can easily lead to a calorie surplus that can lead to weight gain. In addition, high cortisol promotes the accumulation of abdominal fat and can affect metabolism, contributing to weight gain and difficulty regulating blood sugar.

How do I lower cortisol quickly?

When cortisol is elevated in response to acute stress, and not due to other medical causes, it can be naturally reduced through deep breathing techniques, relaxation, or meditation. Regular breaks, moderate exercise, and quality sleep also help reduce acute stress and cortisol.

What is the connection between cortisol and anxiety?

Increased cortisol levels can amplify states of alertness and tension, being directly involved in the biological mechanisms that generate anxiety.

When is the dexamethasone suppression test for cortisol recommended?

The test is performed to confirm the suspicion of hypercortisolism, as well as for the differential diagnosis of the causes of increased cortisol. It allows the doctor to determine whether the excess comes from the pituitary gland, the adrenal glands, or from the administration of corticosteroids.

What are the symptoms of low cortisol?

Low cortisol can manifest as severe fatigue, hypotension, and weight loss. Hyperpigmentation, salt cravings, and episodes of hypoglycemia are also among the symptoms of low cortisol.

Does cortisol influence sleep?

Yes, cortisol plays a key role in regulating the sleep-wake cycle, and elevated levels in the evening can cause insomnia. Circadian rhythm is essential for restful sleep, so it is important that cortisol levels vary consistently throughout the day, starting with morning peaks and gradually decreasing through the evening.

What is the difference between Cushing's syndrome and hypercortisolism?

Hypercortisolism refers to excess cortisol in the body, while Cushing's syndrome represents the clinical form of this excess, with visible symptoms such as hypertension and metabolic disorders.

Can low cortisol cause hypotension?

Yes, low cortisol levels reduce the body's ability to maintain blood pressure, which can lead to hypotension, especially in stressful situations.

Which analysis is more accurate for cortisol: salivary or serum?

The appropriate assay for measuring cortisol depends on the clinical context. Serum cortisol provides a point-in-time measurement of the hormone, salivary cortisol allows for assessment at different times of the day, and urinary cortisol/24h is recommended when Cushing's syndrome is suspected. Your doctor will often recommend a combination of several testing methods to get a complete picture.

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