Adult Growth Hormone Deficiency (AGHD) is a genetic condition concerning growth hormone. Growth hormone is also referred to as somatotropin or somatropin and is a hormone that causes cell growth, cell reproduction, and cell regeneration. This hormone is stored in the anterior pituitary gland. Deficiency of this hormone leads to varying effects, depending on the age at which the deficiency occurs. AGHD refers to two different conditions. The first concerns individuals who are transitioning from childhood to adulthood and who were deficient in the growth hormone as a child. The second condition concerns adults who acquire growth hormone deficiency in adulthood. Growth hormone deficiency in adults is rare and is most commonly caused by a pituitary adenoma, a noncancerous tumor occurring in the pituitary gland. Growth hormone deficiency developed in adulthood can also be caused by childhood traumas, structural lesions, or idiopathic, or spontaneous, growth hormone deficiency, which is very rare. Symptoms of growth hormone deficiency include changes in memory, depression, anxiety, fatigue, fibromyalgia syndrome, central adiposity, decreased sweating and thermoregulation, impaired cardiac function, decreased bone density, decreased muscular mass, and neuromuscular dysfunction. AGHD is diagnosed by dynamic testing. The insulin tolerance test, with 96% sensitivity, is the gold standard of testing, but several other tests are used for diagnosis. These tests include the glucagon stimulation test, combined growth hormone releasing hormone (GHRH) and the arginine test, levodopa, clonidine, and growth-hormone-releasing peptide. The most sensitive and specific of these tests are the insulin tolerance test and combined GHRH and arginine test. Other tests, such as insulin-like growth factor-1 and insulin-like growth factor-binding protein 3, are used for diagnostic assistance.