Understanding low cortisol levels: causes and effects

Medically reviewed by Neka Miller, PhD on November 13, 2020. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Experiencing potential signs or symptoms of cortisol deficiency and interested in learning more about the causes and effects of low cortisol levels? In this quick guide to low cortisol, you’ll find out what cortisol does in the body, the different possible causes and symptoms of low cortisol, how you can easily check levels with an at-home cortisol level test, and more—so keep reading.


What is cortisol’s role in the body?

Cortisol is responsible for regulating how much sugar (glucose) and fat gets stored in your body, and how much is released to use for fuel. It’s also your body’s main stress hormone. When you’re stressed, your adrenal glands release a burst of cortisol to help you cope, temporarily increasing your blood sugar for a boost of energy.

In addition, cortisol also:

  • Controls blood sugar levels in the body
  • Regulates metabolism
  • Serves as an anti-inflammatory
  • Contributes to memory formation
  • Regulates the body’s salt and water balance
  • Affects blood pressure

Cortisol affects nearly every organ system in the body, such as:

  • Nervous system
  • Immune system
  • Cardiovascular system
  • Respiratory system
  • Reproductive system
  • Musculoskeletal system
  • Integumentary system

What causes low cortisol levels?

Cortisol is produced by the adrenal glands, so chronically low cortisol levels (or hypocortisolism) are a form of adrenal insufficiency—meaning the adrenal glands fail to make enough cortisol. Adrenal insufficiency can be broken down into 3 different categories:

  • Primary adrenal insufficiency: Something directly affects adrenal gland function, leading to decreased cortisol production
  • Secondary adrenal insufficiency: The pituitary gland fails to secrete enough of the hormone ACTH—the hormone that tells the adrenal glands how much cortisol is needed
  • Tertiary adrenal insufficiency: The hypothalamus releases an inadequate amount of the hormone CRH—the hormone that tells the pituitary gland to produce ACTH

Let’s now explore each of these possible causes of low cortisol levels in more depth.

Primary adrenal insufficiency (Addison’s disease)

Primary adrenal insufficiency, also referred to as Addison’s disease, is usually brought on by autoimmune processes: the immune system malfunctions—at least partially as a result of genetic factors—and launches an attack on the adrenal glands, impairing their ability to make cortisol (and often other hormones, as well, such as aldosterone). Ultimately, this leads to low cortisol levels.

There are, however, other possible reasons for Addison’s disease—such as infections. In the past, tuberculosis was a common cause, but this has become rarer as treatment has improved. People with AIDS (who have weakened immune systems that cannot effectively fend off infections) are also at a greater risk for Addison’s disease.

Addison’s disease can also be brought on by:

  • Cancerous cells located in the adrenal glands
  • Removal of the adrenal glands through surgery
  • Certain genetic disorders which impact the development or function of adrenal glands
  • Certain antifungal medications

Symptoms of Addison’s disease may develop slowly. Often, it takes an illness or injury to recognize the disease, as the symptoms may worsen during this time.

Signs and symptoms of Addison’s disease include:

  • Extreme fatigue
  • Weight loss
  • Dehydration
  • Decreased appetite
  • Irritability
  • Depression
  • Darkening of the skin (known as hyperpigmentation)
  • Low blood pressure
  • Possible fainting
  • Craving for salt
  • Hypoglycemia (low blood sugar)
  • Nausea
  • Diarrhea
  • Vomiting
  • Pain in the abdomen
  • Muscle or joint pains
  • Loss of body hair
  • Menstrual cycle irregularities

It’s worth pointing out that Addison’s disease is a very rare condition—it’s thought to affect about 1 in every 25,000 people—so having any of the symptoms above could very well be due to something else and should be discussed with your healthcare provider.

Addisonian crisis

Someone with Addison’s disease may be at risk of experiencing a medical emergency known as an Addisonian crisis or adrenal crisis. In an Addisonian crisis, a severe cortisol deficiency suddenly occurs—leading to a potentially life-threatening situation. In many cases, an Addisonian crisis is triggered when:

  • The person has been on long-term treatment with corticosteroids (to help treat Addison’s disease, for example), but then abruptly stops using the medication
  • The person has been on ongoing treatment with corticosteroids, experiences an acute stress event (due to an infection, for example), and does not have their medication dose increased enough—so the body is forced to deplete its own stores of cortisol in response to the stress

An Addisonian crisis can result in low blood levels of sugar, high blood levels of potassium, and high blood pressure. Shock may ensue and ultimately—if the crisis is not treated quickly—coma or death may occur. Because of these potential consequences, if you’ve been diagnosed with Addison’s disease be sure you talk with your healthcare provider to learn what you can do to minimize the risk of an adrenal crisis and any other steps you should take.

Secondary adrenal insufficiency

The pituitary gland—a pea-sized gland situated at the base of the brain—produces adrenocorticotropic hormone (ACTH), which is a hormone that signals to the adrenal glands to make cortisol. Secondary adrenal insufficiency happens when the pituitary gland fails to produce adequate amounts of ACTH, leading to a lack of cortisol production by the adrenal glands and thus low cortisol levels.

Causes of secondary adrenal insufficiency may include:

  • Autoimmune disease
  • Pituitary tumors or infection
  • Pituitary bleeding
  • Genetic diseases affecting pituitary gland development or function
  • Removal of the pituitary gland through surgery
  • Traumatic brain injury

Symptoms of secondary adrenal insufficiency

Many secondary adrenal insufficiency symptoms are similar to those of primary adrenal insufficiency. There are, however, some key differences.

  • Hyperpigmentation: People with secondary adrenal insufficiency do not have hyperpigmentation
  • Dehydration: People with secondary adrenal insufficiency are less likely to experience severe dehydration
  • Blood pressure: People with secondary adrenal insufficiency are less likely to have low blood pressure
  • Low blood sugar: People with secondary adrenal insufficiency are more likely to have low blood sugar

Tertiary adrenal insufficiency

The hypothalamus is a small region of the brain that regulates the pituitary gland’s hormone production. The hypothalamus releases corticotropin-releasing hormone (CRH) to tell the pituitary gland to make ACTH—which, in turn, is the hormone that tells the adrenal glands how much cortisol to make.

Tertiary adrenal insufficiency shows up when something inhibits the release of CRH, which suppresses ACTH levels and ultimately leads to low cortisol levels. This can occur when people who take corticosteroids to treat chronic conditions abruptly come off the medication. This is because prescription doses of corticosteroids significantly elevate the level of cortisol in the blood; when there are high cortisol levels in the blood over an extended period, the hypothalamus makes less CRH.

If you’ve been taking corticosteroids, make sure you always consult with your healthcare provider before making any changes to the treatment schedule. If it’s time to start coming off the medication, your healthcare provider may gradually taper the dosage so your body has time to adjust.

Tertiary adrenal insufficiency can also happen if you’ve had Cushing’s syndrome, a hormonal disorder that leads to high levels of cortisol in the blood (which we’ll cover further below). Sometimes, this syndrome can be caused by tumors in the pituitary or adrenal glands, which make excess amounts of ACTH or cortisol.

When the adrenal tumor is surgically removed, the ACTH or cortisol is gone, and it may take some time for the adrenal function to resume.

What if I have too much cortisol?

Though most of this article has focused on low cortisol levels, it can also be helpful to know more about high cortisol levels.

Over time, too much cortisol in the body can lead to Cushing’s disease (also called Cushing’s syndrome or hypercortisolism). Several different factors can contribute to the development of Cushing’s disease, including pituitary tumors and certain types of medication like steroids.

As opposed to symptoms of low cortisol levels, symptoms of a high cortisol level can include:

  • A round, flushed face
  • Rapid weight gain (most often in the face, chest, and abdomen)
  • Increased blood pressure
  • Osteoporosis
  • Changes in skin, including bruises and purple stretch marks
  • Weakened muscles
  • Mood swings, anxiety, depression, or irritability
  • Increased urination


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