The Adrenal Glands
What Are the Adrenal Glands and What Do They Do?
The body has two adrenal glands, one sitting on top of each kidney. Although small, they are essential for life and help the body respond to stress, maintain energy, and regulate blood pressure.
Each adrenal gland has two main parts, and each part has a different job.
The Inner Part: The Adrenal Medulla
The adrenal medulla produces epinephrine (adrenaline), the hormone responsible for the body’s “fight-or-flight” response.
Epinephrine helps:
Increase heart rate
Raise blood sugar
Direct blood to muscles and vital organs
While the adrenal glands are a major source of adrenaline, similar substances are also released by nerve cells throughout the body. Because of this, problems with the adrenal medulla alone are usually not life-threatening.
The Outer Part: The Adrenal Cortex
The adrenal cortex is essential for survival. It is organized into three layers (called “zones”), and each zone produces different hormones:
1. Aldosterone
Produced in the outer layer (zona glomerulosa)
Controls salt and water balance
Helps regulate blood pressure
Regulated mainly by the kidneys through the renin-angiotensin system, which responds to changes in blood pressure and sodium levels
2. Cortisol
Produced in the middle layer (zona fasciculata)
Helps the body respond to stress
Maintains blood sugar and energy levels
Reduces inflammation
3. Androgens (including DHEA)
Produced in the inner layer (zona reticularis)
These hormones can be converted into estrogen and testosterone
The adrenal glands support the balance of these hormones but are not the main source of sex hormones:
Estrogen is mainly produced in the ovaries (and also in fat tissue)
Testosterone is mainly produced in the testes in men and in smaller amounts in the ovaries in women
How Are Adrenal Hormones Controlled?
Cortisol is regulated by a communication system between the pituitary gland, located at the base of the brain, and the adrenal glands. The pituitary gland releases a hormone called ACTH (adrenocorticotropic hormone), which signals the adrenal glands to produce cortisol as needed.
Aldosterone is controlled mainly by the kidneys, which respond to changes in blood pressure, blood volume, and sodium levels.
When Hormones Are Not Produced or Are Too Low
Addison’s disease (Primary Adrenal Insufficiency)
The adrenal glands do not produce or cannot produce enough cortisol and aldosterone.
Symptoms may include:
Severe fatigue
Weight loss
Low blood pressure
Dizziness
Salt cravings
Secondary Adrenal Insufficiency
Caused by a lack of stimulation from the pituitary gland. Cortisol is low, but aldosterone is usually normal.
When Adrenal Hormones Are Out of Balance
Different conditions can occur when hormone levels are too low or too high.
when Hormones are too high
Cushing’s syndrome (too much cortisol)
Symptoms may include:
Weight gain (especially in the face and abdomen)
Easy bruising
High blood pressure
High blood sugar
Proximal muscle weakness
Primary Aldosteronism (Conn’s syndrome) (too much aldosterone)
Can cause:
High blood pressure
Low potassium
Muscle weakness
Pheochromocytoma (too much epinephrine-like hormones)
A rare tumor that may cause:
Sudden high blood pressure
Rapid heartbeat
Congenital Adrenal Hyperplasia (CAH)
Congenital Adrenal Hyperplasia (CAH) is a genetic condition present from birth that affects how the adrenal glands make hormones.
In CAH:
The body is missing or has low levels of an enzyme needed to produce cortisol
Because of this, the adrenal glands may also not produce enough aldosterone
At the same time, the body may produce too much androgen (male-type hormones)
Symptoms and severity can vary, but CAH may lead to salt loss, low cortisol, and signs of excess androgens. It requires ongoing medical care and monitoring.
Why the Adrenal Glands Matter
The adrenal glands are essential for life. They regulate critical body functions, including:
• Stress response
• Blood pressure
• Energy levels
• Fluid and salt balance
Even though they are small, their role is vital—without properly functioning adrenal glands, the body cannot maintain balance or respond effectively to everyday demands.
When the adrenal glands do not work properly, the consequences can be serious and lifelong.
Underproduction of hormones—particularly cortisol and aldosterone—impairs the body’s ability to respond to stress, illness, or injury and can lead to life-threatening adrenal crises if not properly managed.
Overproduction of adrenal hormones, such as cortisol or aldosterone, can also be harmful. Excess hormone levels may lead to conditions such as high blood pressure, weight gain, muscle weakness, diabetes, and increased risk of cardiovascular complications, significantly affecting overall health and quality of life.
Most adrenal disorders require lifelong management, including:
• Daily medication to replace missing hormones or reduce excess hormone effects
• Regular medical follow-up
• Learning how to adjust treatment during illness, injury, or other physical stress
Living with an adrenal condition requires ongoing awareness and preparation. With appropriate treatment, education, and support, most individuals can lead full and active lives.