Sermorelin is a synthetic ghrelin with 29 amino acid polypeptides, which is the amino-terminal fragment of endogenous growth hormone-releasing hormone (GHRH), and has significant growth-regulating effects. It is proposed that neuropeptides/neurotransmitters, hormones and cytokines are the "common language" for the mutual regulation of the nervous system, endocrine system and immune system. The immune system is also regulated by the neuro-endocrine-immune network in addition to its very fine regulation mechanism.