Macimorelin (AEZS 130) is an orally active, small-molecule, peptidomimetic growth hormone secretagogue receptor (GHSR1A) agonist (ghrelin analogue), being developed by AEterna Zentaris for the diagnosis of adult growth hormone deficiency (AGHD; somatotropin deficiency), and for the treatment of cachexia associated with chronic disease such as AIDS and cancer. Macimorelin was approved by the FDA in December 2017 under the market name Macrilen for oral solution. Macimorelin stimulates GH release by activating growth hormone secretagogue receptors present in the pituitary and hypothalamus. Macimorelin has been granted orphan drug designation by the FDA for diagnosis of AGHD.