Growth hormones like the human growth hormone (HGH) are secreted by the pituitary gland in the brain. They are necessary for healthy growth, the regulation of the metabolism and to keep the tissues and muscles healthy. Too much growth hormones can cause children to go too much, and too little can inhibit them from growing normally. In adults, abnormal levels can indicate a problem, such as a tumor of the pituitary gland, called an adenoma. Too much growth hormone can also cause the bones of the feet, hands, jaw and face grow larger than normal, known as acromegaly.

HGH also causes the release of the IGF-1 hormone. Therefore a blood test that measures IGF-1 acts like a biomarker for blood levels of HGH. The IGF-1 hormone is produced by the liver and other tissues that affect glucose metabolism and other growth activities. Measuring this hormone assesses the levels of HGH and confirms abnormal levels.

The test is done to see if a child who has not grown as expected may have gigantism or dwarfism or if an adult has acromegaly or a tumor of the pituitary gland. Keeping levels within optimal range is also part of an anti-aging treatment that involves growth hormone therapy. Although controversial, growth hormones are used as an anti-aging treatment. It arguably provides such benefits as an increased metabolism, increased muscle mass and decreased fat. Some adults may also experience increased bone density and a greater capacity for exercise.