Sermorelin — Published Research

Sermorelin binds to the GHRH receptor (GHRHR), a class B G protein-coupled receptor expressed primarily on anterior pituitary somatotroph cells. Ligand binding activates Gαs, stimulating adenylyl cyclase and elevating intracellular cAMP. This triggers PKA-mediated phosphorylation of CREB transcription factor, leading to increased GH gene transcription and pulsatile GH release. The first 29 residues of GHRH contain all determinants required for full receptor binding affinity (Kd ~0.3 nM) and maximal cAMP stimulation.

Mayo KE et al. “Regulation of the pituitary somatotroph cell by GHRH and its receptor.” Recent Prog Horm Res. 2000. PubMed

Pharmacokinetic studies in healthy adults demonstrated that sermorelin produces peak plasma concentrations within 5–20 minutes, with a half-life of approximately 11–12 minutes. Despite the short half-life, the peptide stimulates a GH pulse lasting 2–3 hours. Repeated use preserved the pulsatile pattern of GH secretion without desensitization of somatotroph responsiveness, as measured by 24-hour GH profiling with frequent sampling.

Prakash A, Goa KL. “Sermorelin: A review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency.” BioDrugs. 1999. PubMed

A 6-month study in healthy older adults (ages 55–71) measured sermorelin’s effects on sleep architecture using polysomnography. The research characterized changes in non-REM slow-wave sleep (stages 3 and 4) duration and GH secretory events during sleep. Given that endogenous GHRH pulses are temporally coupled with slow-wave sleep onset, the study investigated whether exogenous GHRH analog administration altered this physiological relationship.

Vitiello MV et al. “Long-term improvement in measures of nighttime sleep and morning alertness following growth-hormone-releasing-hormone treatment in healthy elderly.” J Clin Endocrinol Metab. 2006. PMC