Changes in pituitary function with ageing and implications for patient care Nature Reviews Endocrinology 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 Endocrine Diseases Springer Nature Link Normal Physiology of ACTH and GH Release in the Hypothalamus and Anterior Pituitary in Man Endotext NCBI Bookshelf Corticotropin Like Intermediate Peptide an overview ScienceDirect Topics