Somatorelin is 29 amino acid analogue of human growth hormone-releasing hormone used as a diagnostic agent for determining growth hormone deficiency. Growth-hormone-releasing hormone (GHRH, somatoliberin) is the hypothalamic peptide hormone that specifically stimulates synthesis and release of growth hormone (GH, somatotropin) by somatotrope cells of the anterior pituitary gland. The hypothalamic hormone growth hormone (GH)-releasing hormone (GHRH) acts on specific GHRH receptors (GHRH-R) in the anterior pituitary gland to stimulate the synthesis and secretion of GH and to promote somatotrope expansion. Somatorelin is applied to determine the somatotropic function of the anterior pituitary gland in cases of suspected growth hormone deficiency. The test distinguishes between pituitary and hypothalamic disorders but is not suitable as a screening test for growth hormone deficiencies. Somatorelin has been used in trials studying the treatment of Aging, Elderly, Sleep Disorders, Hormone Deficiency, and Mild Cognitive Impairment.