Growth Hormone: Testing, Levels, and Effects on Health

What Is Growth Hormone?

Growth hormone (GH), also known as somatotropin, is a hormone produced by the pituitary gland, a small organ located at the base of the brain. 

GH plays a key role in growth regulation, especially during childhood and adolescence. It influences the body's ability to build muscles, break down fats, and maintain a healthy metabolism. 

GH also helps to control the production of protein and supports the development of bones.

It is often measured to assess problems related to growth in children and metabolic issues in adults. 

Abnormal GH levels can indicate disorders of the pituitary gland or other health conditions that affect growth and metabolism.

When Is Growth Hormone Testing Recommended?

GH testing is prescribed when there is suspicion of abnormal growth hormone production in the body. This is often indicated by symptoms related to growth, metabolism, or bone health.

GH testing may be recommended in the following cases:

• Unexplained short stature or slow growth in children.
• Delayed puberty or development issues.
• Symptoms of acromegaly (enlarged facial bones and hands) in adults.
• Fatigue and weakness due to potential hormonal imbalances.
• Low bone density or osteoporosis.
• Abnormal cholesterol levels or lipid metabolism disorders.

How Is Growth Hormone Testing Conducted?

To measure growth hormone levels, a venous blood test is typically performed. Since GH levels fluctuate throughout the day, special testing methods may be used to get accurate results. 

These tests include stimulation or suppression tests that help to assess how the pituitary gland is functioning.

• Stimulation test: This test is used to check if the body is producing enough growth hormone. The patient may be asked to fast for 10-12 hours before the test. A solution, such as insulin or arginine, is injected, and blood is drawn at specific intervals to monitor the response.
• Suppression test: This test measures if the body is producing too much growth hormone. The patient fasts, and a glucose solution is given. Blood samples are then taken to see how well GH production is suppressed by the glucose.

No specific preparations are needed other than fasting as instructed by the healthcare provider. Avoiding certain medications or stressful activities before the test may also be recommended, as these can affect hormone levels.

What Are the Normal Growth Hormone Levels?

The normal range of growth hormone levels can vary depending on the person's age and gender. Below are the typical GH ranges:

Children

• Up to 6 years old: 0.10-6.20 ng/ml
• 6 to 17 years old (males): 0.05-11.00 ng/ml
• 6 to 17 years old (females): 0.05-17.30 ng/ml

Adults

• Males: 0-3.00 ng/ml
• Females: 0-8.00 ng/ml

Note: The units of measurement and the normal ranges can differ depending on the laboratory and the specific methods used

What Do Abnormal Levels Mean?

Growth Hormone High Levels

High levels of growth hormone can indicate the presence of certain health conditions, usually related to excessive pituitary gland activity.

• Pituitary adenoma: A benign tumor of the pituitary gland that causes overproduction of growth hormone.
• Acromegaly: A condition in adults characterized by the thickening of bones, especially in the face, hands, and feet.
• Gigantism: A condition in children that results in excessive height and large body size due to overproduction of growth hormone during childhood.
• Hypokalemia: Low potassium levels may cause disturbances in GH production.

• Follow up with regular monitoring and imaging tests to assess the size of the pituitary gland.
• Consult a healthcare provider to discuss potential treatments to reduce hormone levels.
• Maintain a healthy diet and lifestyle to manage symptoms of acromegaly or gigantism.
• Surgery may be recommended in cases of tumors affecting the pituitary gland.

Growth Hormone Low Levels

Low levels of growth hormone can lead to conditions that affect physical growth, development, and metabolism.

• Pituitary dwarfism (nanism): A condition where growth is significantly stunted due to inadequate production of GH.
• Growth retardation: Slower than normal growth in children, often due to issues with the pituitary gland.
• Cushing’s syndrome: Overproduction of cortisol in the body can interfere with growth hormone production.
• Hypopituitarism: A condition where the pituitary gland fails to produce one or more of its hormones, including growth hormone.

• Hormonal therapies may be prescribed by your healthcare provider to increase GH levels.
• Regular monitoring of growth and development in children is important.
• Maintaining a healthy diet rich in protein and essential nutrients can help support normal growth.
• Physical activity and strength training can promote better growth and bone density in those with low GH levels.

Which Specialist Should You Consult?

For concerns about growth hormone levels, it's best to consult with an endocrinologist, who specializes in hormone-related issues. Depending on the age and symptoms of the patient, a pediatrician (for children) or an internist (for adults) may also be involved in the diagnosis and treatment.