Human growth hormone (GH) is produced by the pituitary gland. It is essential for growth and plays an important role in how the body uses food for energy (a process called metabolism). The amount of GH in the blood changes throughout the day and is affected by exercise, sleep, emotional stress, and diet.

Too much GH during childhood can result in excessive growth (gigantism). Too little GH during childhood can inhibit growth (dwarfism). However, gigantism and dwarfism can be treated if discovered early.

In adults, excess GH is usually caused by a noncancerous tumor of the pituitary gland called an adenoma. Excess GH can lead to an abnormal bony enlargement of the face, jaw, hands, and feet (acromegaly).

Growth hormone can cause the release of other substances (factors) that affect growth. One of these is insulin-like growth factor 1 (IGF-1). When the GH level is abnormally high, the IGF-1 level is usually high as well. A test for IGF-1 may be done to confirm high GH levels.

This test is done on a blood sample taken from a vein. Two blood samples (taken 1 day apart) may be collected.

Growth Hormone
Results

Normal

Normal results may vary from lab to lab.

After physical or emotional stress (such as exercise or worry about health problems), growth hormone (GH) levels are normally about 20 to 30 ng/mL.

Greater than normal values may mean

• High growth hormone (GH) values may indicate gigantism or acromegaly. These conditions are often the result of a noncancerous tumor in the pituitary gland (adenoma).
• Increased GH levels may also result from diabetes, kidney disease, or starvation.