Growth hormone (GH) is made naturally by the body and is essential for normal development in children and adolescents. It supports the growth of bones and other tissues and helps regulate blood sugar levels.
In typical conditions, growth hormone is produced by the pituitary gland, a small gland located at the base of the skull. A synthetic form can also be produced in a laboratory and is used in medications to treat certain growth and development problems.
Some adults take growth hormone (GH) without scientific support, hoping to slow the aging process or build muscle. However, such use is not recommended and can lead to side effects that outweigh any potential benefits.
Main functions
Growth hormone (GH) plays an essential role in development and metabolism and is responsible for:
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Helping a child reach expected height and development;
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Stimulating the growth of bones and tissues, especially during childhood and adolescence;
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Regulating how the body uses food to produce energy;
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Keeping blood sugar within a healthy range.
In addition, growth hormone helps maintain the structure of tissues and organs even after growth has ended.
Indications for testing
Testing to evaluate growth hormone (GH) is ordered by a pediatrician or endocrinologist, usually when delayed growth or hormone deficiency is suspected.
Testing is done carefully because GH is released at different times during the day, which makes a single blood draw insufficient for diagnosis.
The process often involves multiple tests, with the main one being a stimulation test, in which the person receives an intravenous medication to trigger GH release. Blood samples are then collected every 15 to 30 minutes over a period of 2 to 5 hours.
Normal GH values can vary depending on the test used by the lab. In general, reference values are 10 to 50 ng/mL in children, 0.4 to 10 ng/mL in adult men, and 1 to 14 ng/mL in adult women.
In addition, the doctor may order specific blood tests that measure proteins IGF-1 and IGFBP-3, which are related to how GH works in the body.
Elevated levels
Elevated levels of growth hormone (GH) are often linked to benign tumors of the pituitary gland, called adenomas, which can lead to excessive growth.
In children, elevated GH may lead to gigantism, which is characterized by a height far above what is expected.
In adults, excess GH can cause acromegaly, with enlargement of the hands, feet, bones, and organs, and may lead to complications such as high blood pressure, diabetes, and heart problems.
GH can also rise naturally throughout the day, especially during deep sleep, after intense exercise, or during stress or hypoglycemia.
Low levels
Growth hormone (GH) may be low in the following situations:
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Adenomas or other tumors in the pituitary gland;
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Pituitary surgery or trauma;
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Radiation therapy or chemotherapy involving the brain;
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Inflammation or infections affecting the pituitary gland;
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Congenital problems in pituitary development, such as Turner syndrome and Prader-Willi syndrome;
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Chronic kidney disease.
GH deficiency that starts in childhood may continue into adulthood and can be associated with increased body fat, reduced sense of well-being, higher risk of heart disease, and weakening of bones, muscles, and the heart.
Indications for use
Using growth hormone in its synthetic form is only indicated for specific health conditions and should always be done under medical supervision, usually with a pediatrician or endocrinologist.
In children, treatment aims to stimulate growth when there is hormone deficiency, helping the child reach expected adult height.
Treatment continues until the child stops growing, meaning until the growth plates close.
During this period, lab testing and medical appointments are typically needed every 3 to 6 months. If the deficiency persists into adolescence, treatment may continue at lower doses.
In adults, synthetic GH may be indicated in specific situations, such as weight and muscle loss caused by HIV/AIDS or short bowel syndrome.
In these cases, GH replacement may provide benefits such as improved physical capacity, increased muscle and bone mass, reduced body fat, and improved quality of life.
Injectable growth hormone
Growth hormone is usually given as a daily subcutaneous injection, typically at bedtime, following the doctor’s instructions. The dose is adjusted based on body weight and the goal of treatment.
Treatment duration varies depending on the need, but in some cases it may be used from childhood through the end of adolescence.
Side effects
Possible side effects of growth hormone use include:
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Joint and muscle pain;
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Swelling in the arms and legs;
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Carpal tunnel syndrome;
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Increased insulin resistance and/or increased risk of type 2 diabetes;
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Increased breast tissue in men (gynecomastia).
In general, these effects are not seen in children, but they may occur in adults.
In rare cases, headache, increased intracranial pressure, high blood pressure, and ringing in the ears may occur.
Contraindications for use
Growth hormone should not be used by people who are pregnant or by those with a history of cancer or a benign intracranial tumor.
Use of growth hormone should be carefully evaluated in people with diabetes, diabetic retinopathy, untreated hypothyroidism, or psoriasis.
Synthetic growth hormone is contraindicated for cosmetic or performance purposes, because these uses are considered unsafe and there is no evidence of benefit in these situations.