Sermorelin

The original synthetic GHRH analog corresponding to the first 29 amino acids of endogenous GHRH, with a history of clinical use for GH deficiency diagnostics.

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Overview

Sermorelin (Sermorelin acetate, also known as GRF 1-29 NH2 or GHRH(1-29)) is a synthetic peptide corresponding to the first 29 amino acids of endogenous human growth hormone-releasing hormone (GHRH 1-44). These 29 amino acids represent the minimum fragment required for full biological activity at the GHRH receptor.

Sermorelin was previously FDA-approved under the brand name Geref® as a diagnostic agent for assessing pituitary GH reserve and for the treatment of idiopathic GH deficiency in children. While the branded product was discontinued for commercial reasons (not safety), Sermorelin continues to be widely used in research and is available through compounding. It represents one of the most well-characterized GHRH analogs in clinical literature.

Mechanism of Action

Sermorelin binds directly to the GHRH receptor (GHRHR) on somatotroph cells in the anterior pituitary. The GHRHR is a class B G protein-coupled receptor that activates the Gs/adenylyl cyclase/cAMP/PKA signaling cascade.

cAMP-mediated PKA activation has two key effects: (1) acute stimulation of GH vesicle exocytosis, producing a rapid pulse of GH release, and (2) longer-term upregulation of GH gene (GH1) transcription through CREB phosphorylation, increasing the pituitary’s GH synthetic capacity.

As a native-sequence GHRH fragment (without the DPP-IV-resistant modifications of CJC-1295), Sermorelin has a relatively short half-life of approximately 10-20 minutes. This short duration results in acute, physiological GH pulses and makes it useful for diagnostic GH stimulation testing. However, the rapid degradation by DPP-IV necessitates more frequent administration for sustained research protocols.

Key Research Findings

• Clinical Validation: Extensive clinical data from FDA-approved use demonstrated reliable GH stimulation in subjects with intact pituitary function, establishing Sermorelin as a reference GHRH agonist.
• Pituitary Reserve Testing: Research confirms Sermorelin’s utility as a diagnostic agent — robust GH response indicates intact somatotroph function, while a blunted response suggests pituitary dysfunction.
• Pediatric GH Deficiency: Clinical studies in children with idiopathic GH deficiency showed significant increases in growth velocity and IGF-1 levels with chronic Sermorelin administration.
• Sleep-Related GH Enhancement: Research indicates that Sermorelin administration amplifies nocturnal GH pulses, particularly when administered before sleep onset.
• Safety Profile: Long-term clinical use data demonstrate an excellent safety profile with minimal adverse effects, primarily limited to injection site reactions and transient flushing.

Research Applications

• Pituitary GH reserve assessment and diagnostics
• GHRH receptor pharmacology and signaling studies
• Age-related GH decline (somatopause) research
• Pediatric growth disorder investigations
• Sleep-associated GH secretion studies
• Comparison standard for novel GHRH analogs

Dosing Protocols (Research Use Only)

Note: Dosing information is compiled from published research literature and is intended for reference purposes only.

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