Low Cortisol Levels: Symptoms, Causes & Treatment

Updated in January 2024

Low cortisol levels are characterized by values in the blood that are less than 5 µg/dL in the morning. It can cause symptoms such as fatigue, reduced appetite, weight loss and mood swings.

Cortisol is a hormone that is produced by the adrenal glands. Low cortisol levels may be a sign of adrenal gland inflammation, tumors, infections, or suddenly discontinuing corticosteroid medications.

If you suspect you have low cortisol levels, it is important to consult your family doctor or an endocrinologist. Treatment for this finding depends on the underlying cause, and typically involve hormone replacement through medications such as prednisone or hydrocortisone.

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Main symptoms

The main signs and symptoms of low cortisol levels are:

  • Fatigue
  • Lack of energy
  • Decreased appetite
  • Joint pain
  • Mood changes, such as irritability, depression and apathy
  • Drop in blood sugar levels
  • Low blood pressure
  • Weight loss

In pregnant women, low cortisol, if left untreated, can lead to complications like abnormalities in the development of fetal organs, like the lungs, eyes, skin and brain. Therefore, if you notice the above symptoms during pregnancy, you should advise your OBGYN for assessment and treatment as needed.

Adrenal gland disorders can also lead to Addison's disease. This condition can cause a drop in cortisol, as well as a drop in other hormones like aldosterone and androgen hormones.

Confirming a diagnosis

Low cortisol levels are usually diagnosed by an endocrinologist or family doctor, who will review blood test results and take the presenting symptoms into account. 

The doctor may also order additional testing, such as bloodwork to check adrenocorticotropic hormone (ACTH) levels, sodium and potassium, or an MRI.

Common causes

The main causes of low cortisol are:

  • Inflammation of the adrenal glands, due to a reaction from abnormal antibodies produced by the body
  • Use of medications, such as ketoconazole, fluconazole, carbamazepine and phenytoin
  • Bleeding that affects the adrenal glands, due to a clotting disorder or use of anticoagulants 
  • Infections, such as HIV, syphilis or tuberculosis
  • Sudden suspension of corticosteroid medications, especially when used for prolonged durations or in high doses
  • Surgical removal of the adrenal glands, known as adrenalectomy
  • Tumors or metastases, especially when they affect the pituitary or adrenal glands

Adrenal gland inflammation is the most common cause of low cortisol levels. This is most common in people with autoimmune diseases such as type 1 diabetes or vitiligo. 

Treatment options

The treatment of low cortisol levels can be done by replacing this hormone, using corticosteroid medications, such as prednisone or hydrocortisone, as prescribed by an endocrinologist.

In addition, the doctor may also recommend the replacement of other hormones produced by the adrenal glands, such as androgens and mineralocorticoids.

Depending on the cause of the low cortisol levels, treatment may also involve chemotherapy, radiation therapy and/or surgery, in the case of tumors. Low levels caused by autoimmune disease or infections can also be corrected through the treatment of these conditions.