What does low cortisol mean, and what causes it?

Low cortisol, also known as hypocortisolism or adrenal insufficiency, means your body isn’t producing enough of the hormone cortisol. Cortisol is made in the adrenal glands—small organs that sit on top of your kidneys—and plays a vital role in:

• Regulating blood sugar
• Controlling inflammation
• Helping your body respond to stress
• Maintaining blood pressure
• Balancing salt and water in your body

When cortisol levels drop too low, normal body functions can start to slow or fail, leading to a range of symptoms and health concerns.

Signs and Symptoms of Low Cortisol

Symptoms can develop gradually or appear suddenly in an adrenal crisis. Common signs include:

• Chronic fatigue and weakness
• Dizziness or lightheadedness when standing up (orthostatic hypotension)
• Unintentional weight loss and decreased appetite
• Nausea, vomiting or abdominal pain
• Muscle or joint aches
• Salt cravings
• Irritability, depression or mood swings
• Low blood sugar (hypoglycemia)
• Darkening of the skin (in primary adrenal insufficiency)

In an acute adrenal crisis, you may experience severe low blood pressure, confusion, dehydration, high fever and even loss of consciousness. This is a medical emergency.

Main Causes of Low Cortisol

Low cortisol arises from problems in one of three places along the “HPA axis” (hypothalamus-pituitary-adrenal axis):

1. Primary Adrenal Insufficiency (Addison’s Disease)
   • The adrenal glands themselves are damaged and can’t make enough cortisol (and often aldosterone).
   • Common causes: autoimmune destruction, infections (e.g., tuberculosis), bleeding into the gland, genetic disorders.

2. Secondary Adrenal Insufficiency
   • The pituitary gland in the brain doesn’t release enough ACTH (adrenocorticotropic hormone), which normally signals the adrenals to produce cortisol.
   • Causes: pituitary tumors or surgery, radiation therapy, traumatic brain injury, certain medications.

3. Tertiary Adrenal Insufficiency
   • The hypothalamus fails to produce enough CRH (corticotropin-releasing hormone), leading to reduced ACTH and cortisol.
   • Often linked to long-term use of oral corticosteroids (e.g., prednisone) that suppress the HPA axis. Stopping steroids abruptly without tapering can trigger this.

Other factors that may contribute:

• Infections (e.g., HIV, fungal infections)
• Genetic enzyme deficiencies affecting cortisol synthesis
• Medications that interfere with adrenal function

How Low Cortisol Is Diagnosed

Diagnosing low cortisol involves a combination of medical history, physical exam and lab tests:

1. Blood Tests
   • Morning serum cortisol (levels are normally highest upon waking)
   • ACTH level (to distinguish primary from secondary insufficiency)

2. ACTH Stimulation Test
   • Synthetic ACTH is given, and cortisol levels are measured before and after. A blunted rise suggests adrenal insufficiency.

3. Additional Hormone Panels
   • Aldosterone and renin (to assess salt-regulating hormones)
   • Electrolytes (sodium, potassium)

4. Imaging Studies
   • CT scan or MRI of adrenal glands or pituitary gland if structural damage is suspected.

Treatment Options

Treatment aims to replace missing hormones, address the cause and prevent adrenal crisis:

• Glucocorticoid Replacement
– Hydrocortisone is the most common replacement for cortisol.
– Dosing mimics natural daily rhythms (higher in morning, lower in afternoon).

• Mineralocorticoid Replacement (primary insufficiency)
– Fludrocortisone helps maintain salt balance and blood pressure.

• Managing Underlying Causes
– Surgery or radiation for pituitary tumors.
– Treating infections or switching medications that suppress the HPA axis.

• Adrenal Crisis Prevention
– Wear a medical alert bracelet.
– Carry injectable hydrocortisone for emergencies.
– Plan “sick day” dosing: increase glucocorticoid dose during illness or stress.

Living with Low Cortisol

Adjusting to life with low cortisol involves:

• Regular follow-up with an endocrinologist
• Understanding your medication schedule and never skipping doses
• Recognizing early signs of adrenal crisis (severe fatigue, nausea, low blood pressure)
• Wearing medical ID and keeping emergency contacts informed
• Monitoring for side effects of hormone replacement

When to Seek Help

If you experience any of the following, seek medical care immediately:

• Sudden severe weakness, dizziness or confusion
• Unexplained high fever, vomiting or diarrhea
• Signs of dehydration (dry mouth, decreased urination)
• Severe abdominal pain or chest discomfort

For initial guidance, you might consider a free, online symptom check, using the doctor approved Ubie Symptom Checker to help determine if you need urgent evaluation.

Key Takeaways

• Low cortisol means your body can’t produce enough of this critical stress-hormone.
• Causes range from adrenal gland damage to pituitary or hypothalamus dysfunction.
• Symptoms include persistent fatigue, dizziness, abdominal issues and mood changes.
• Diagnosis relies on blood tests, stimulation tests and imaging.
• Treatment involves hormone replacement, managing triggers and emergency planning.
• Always keep a plan in place for adrenal crises and wear medical identification.

If you suspect low cortisol or experience serious symptoms, speak to a doctor right away. Timely diagnosis and proper treatment can manage your condition effectively and help you maintain a healthy, active life.