CP21R7 (CP21) is primarily used in research settings as a selective agonist for the relaxin family peptide receptor 1 (RXFP1). Its main application lies in studying cardiovascular function, where it demonstrates potential for promoting vasodilation and improving blood flow. It has been investigated for its role in reducing blood pressure and protecting against ischemic injury in heart tissue. Due to its ability to mimic the effects of relaxin, CP21 is also explored in fibrosis research, showing promise in reducing tissue scarring in organs such as the heart and liver. Additionally, it is used as a pharmacological tool to understand receptor signaling pathways involved in pregnancy, inflammation, and tissue remodeling. Its stability and selectivity make it suitable for in vivo and in vitro experiments aimed at developing therapies for chronic heart failure and other fibrotic diseases.