Difference Between GHRP 2 and GHRP 6 Peptides Comparison 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 SERMORELIN GHRP 2 is a growth hormone secretagogue AAI Peptides vs TRT: Benefits, Side Effects & How Long It Takes to Work Figure 3 from Ipamorelin, the first selective growth hormone secretagogue. Semantic Scholar