The role of cortisol and prolactin in the pathogenesis and clinical expression of psychotic disorders ScienceDirect Cortisol Disorders Prolactin ScienceDirect Ipamorelin is a pentapeptide. Five amino acids. That's it. But three of those five don't exist in nature. The sequence: Aib His D 2 Nal D Phe Lys, with a C terminal amide. Position 1 is aminoisobutyric acid the Normal Physiology of ACTH and GH Release in the Hypothalamus and Anterior Pituitary in Man Endotext NCBI Bookshelf Normal Physiology of ACTH and GH Release in the Hypothalamus and Anterior Pituitary in Man Endotext NCBI Bookshelf