From the Guidelines
Low morning cortisol levels are most commonly caused by adrenal insufficiency, which can be primary or secondary, and can also be influenced by factors such as chronic stress, certain medications, sleep disorders, nutritional deficiencies, and chronic inflammatory conditions. The causes of low morning cortisol levels can be multifaceted, including:
- Adrenal insufficiency, which can be primary (Addison's disease) or secondary, resulting from pituitary gland dysfunction that reduces ACTH production 1
- Chronic stress, which can deplete cortisol over time, leading to adrenal fatigue and low morning levels
- Certain medications like opioids, glucocorticoids, and some psychiatric drugs, which can suppress cortisol production 1
- Sleep disorders, particularly disrupted sleep patterns or sleep apnea, which can interfere with the normal cortisol rhythm
- Nutritional deficiencies, especially in vitamins B5, B12, and C, which can impair adrenal function
- Chronic inflammatory conditions and autoimmune disorders, which may also affect cortisol production
- Pituitary tumors, which can disrupt ACTH secretion, while genetic disorders like congenital adrenal hyperplasia can cause enzyme deficiencies affecting cortisol synthesis 1 It is essential to note that the diagnosis and management of adrenal insufficiency should be guided by the relationship between ACTH and cortisol levels, as primary and secondary adrenal insufficiency can be distinguished by this relationship 1. If experiencing symptoms like fatigue, dizziness, and weakness, medical evaluation is essential as treatment depends on the underlying cause, and education on stress dosing and a medical alert bracelet for adrenal insufficiency is crucial to trigger stress-dose corticosteroids by emergency medical personnel 1.
From the Research
Causes of Low Morning Cortisol Levels
Low morning cortisol levels can be caused by various factors, including:
- Primary adrenal insufficiency (AI), which is an endocrine disorder in which hormones of the adrenal cortex are produced to an insufficient extent 2, 3
- Secondary adrenal insufficiency, which is due to a lack of stimulation via pituitary adrenocorticotropic hormone or hypothalamic corticotropin-releasing hormone 3
- Inadequate secretion of glucocorticoid and/or mineralocorticoid secretion from the adrenal cortex 3
- Failure of the adrenal gland or pituitary gland to produce sufficient hormones 2, 3
- Certain medical conditions, such as Addison's disease 2, 3
Diagnosis and Testing
Diagnosis of low morning cortisol levels can be made through:
- Morning serum cortisol level test, where a level >13 mcg/dL reliably rules out adrenal insufficiency 4
- Cosyntropin stimulation test (CST), which is used to confirm the diagnosis of primary or secondary adrenal insufficiency 3, 4
- Insulin tolerance test, which is the gold standard for secondary adrenal insufficiency 3
Treatment and Management
Treatment and management of low morning cortisol levels typically involve:
- Glucocorticoid replacement therapy, which aims to replicate the natural circadian rhythm of cortisol release 5
- Individualized cortisol exposure and management of patients during infections and other stress-related events 5
- Education and empowerment of patients to take control of their own medical management 3