Used in cardiovascular research to study its role in regulating blood pressure and heart function. It acts as a potent agonist for the APJ receptor, making it valuable in exploring treatments for heart failure and hypertension. Additionally, it is investigated for its potential in improving vascular function and its effects on fluid homeostasis. Researchers also examine its role in metabolic regulation and its possible therapeutic applications in diabetes and obesity. Its stability and receptor-binding properties make it a key tool in understanding apelin signaling pathways.