Sermorelin: The GHRH(1-29) Fragment in Growth Hormone Secretagogue Research
Research Use Only. This article is for scientific and educational reference only. All products are sold for research purposes and are not intended for human or animal consumption.
Overview
Sermorelin (CAS 86168-78-7), also known as GHRH(1-29), is a synthetic peptide comprising the first 29 amino acids of the 44-amino acid endogenous growth hormone-releasing hormone. This N-terminal fragment retains full biological activity at the GHRH receptor, making sermorelin a functionally equivalent but shorter and more easily synthesized alternative to full-length GHRH for research applications.
With a molecular weight of approximately 3,358 Da and the amino acid sequence Tyr-Ala-Asp-Ala-Ile-Phe-Thr-Asn-Ser-Tyr-Arg-Lys-Val-Leu-Gly-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Met-Ser-Arg-NH₂, sermorelin has been used in both diagnostic and research settings. Its plasma half-life is approximately 10–20 minutes, reflecting rapid enzymatic degradation by DPP-IV and other proteases.
Mechanism of Action
Sermorelin binds to the GHRH receptor (GHRHR) on somatotroph cells of the anterior pituitary, activating adenylyl cyclase through Gs protein coupling. The resulting increase in intracellular cAMP stimulates both the synthesis of growth hormone and its pulsatile release into the systemic circulation. The physiological feedback mechanisms of the GH axis — including somatostatin-mediated inhibition and IGF-1 negative feedback — remain intact with sermorelin administration, distinguishing it from direct GH replacement.
The short half-life of sermorelin means that its effects are transient and closely mimic the natural pulsatile pattern of GHRH secretion from the hypothalamus. This property has made sermorelin useful in research contexts where preservation of physiological GH pulse patterns is important, as well as in diagnostic protocols for assessing pituitary GH reserve.
Key Research Findings
Sermorelin has a well-established research history as a diagnostic agent for GH deficiency. The GHRH stimulation test using sermorelin has been used to differentiate pituitary from hypothalamic causes of GH deficiency, with studies demonstrating that subjects with hypothalamic GHRH deficiency respond to sermorelin with GH release, while those with primary pituitary failure do not.
Research in aging populations has examined sermorelin's potential to partially restore age-related decline in GH secretion. Studies have reported increases in IGF-1 levels, improvements in sleep quality (particularly slow-wave sleep, during which GH secretion is highest), and modest improvements in body composition with sermorelin administration. The peptide has also been studied in models of GH-deficient children, where it demonstrated efficacy in stimulating linear growth.
Chemical Properties
| Property | Value | |---|---| | Sequence | GHRH(1-29)-NH₂ | | Molecular Weight | ~3,358 Da | | CAS Number | 86168-78-7 | | Half-life | ~10–20 minutes | | Form | Lyophilized powder | | Purity (research grade) | ≥99% HPLC | | Storage | −20°C, protect from light |
Research Considerations
Sermorelin's short half-life necessitates careful timing of administration relative to blood sampling in GH research protocols. The peptide is typically administered in the evening in clinical research to coincide with the nocturnal GH surge. Reconstitution with bacteriostatic water is standard, and reconstituted solutions should be refrigerated and used within 30 days.
Research Use Only. This article is for scientific and educational reference. All products are sold for research purposes only and are not intended for human or animal consumption.