Sermorelin - Frequently Asked Questions

Sermorelin is a growth hormone-releasing hormone (GHRH) receptor agonist and growth hormone secretagogue. Specifically, it is a 29-amino-acid GHRH analogue corresponding to the N-terminal 1-29 fragment of human GHRH, and it retains the full intrinsic activity of the parent peptide at the GHRH receptor.

The sequence is 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, or in one-letter code YADAIFTNSYRKVLGQLSARKLLQDIMSR-NH2. It corresponds to residues 1-29 of endogenous human GHRH and is the shortest fragment retaining full GHRH biological activity.

The average molecular weight is 3357.93 g/mol as the free base, and the molecular formula is C149H246N44O42S. These values are the basis for molar concentration calculations and mass-spectrometric identity confirmation in laboratory work.

Two CAS Registry Numbers apply: 86168-78-7 for the free base and 114466-38-5 for the acetate salt. The two numbers distinguish the salt forms, which matters for accurate mass accounting since acetate counterions add to the as-supplied weight.

It targets the GHRH receptor (GHRHR), a Gs-coupled class B G-protein-coupled receptor on anterior-pituitary somatotrophs. Agonist binding couples the receptor to Gs, activates adenylyl cyclase, raises intracellular cAMP, and engages PKA and CREB-mediated transcription, promoting GH-1 gene transcription and Ca2+-dependent exocytosis of growth-hormone granules.

The carboxy-terminal arginine is amidated (Arg29-NH2), and this amidation is required for receptor potency. It is a structure-function feature, not just notation, so quality checks of a preparation should confirm the amide form, and the 3357.93 g/mol mass corresponds to this amidated species.

It is rapidly cleaved by dipeptidyl peptidase-IV (DPP-IV) at the Tyr1-Ala2 bond, giving a short plasma half-life on the order of minutes. This N-terminal cleavage site is the molecule's principal metabolic vulnerability and is a focal point of stability and analogue-design research.

For laboratory use, lyophilized peptide is reconstituted in bacteriostatic water, added gently down the vial wall, to form a clear stock. Concentration is calculated from the 3357.93 g/mol weight: 1 mg in 1 mL gives 1 mg/mL, approximately 298 micromolar. This describes laboratory preparation only, not any human dosing protocol.

Reconstituted stock is handled cold, protected from light and agitation, and split into single-use aliquots to avoid repeated freeze-thaw cycles. Lyophilized, sealed material is the more stable reserve form. Given the peptide's documented DPP-IV lability, minimizing ambient-temperature exposure is prudent. Specific shelf-life figures are not provided in the source data.

Research areas include GHRHR binding and Gs-cAMP-PKA signal transduction in somatotroph models, in-vitro and ex-vivo pituitary GH secretory dynamics and pulsatility, comparative pharmacology versus GHS-R secretagogues, DPP-IV cleavage kinetics and structure-activity relationships, use as a provocative agent for probing GH-secretory reserve, and somatostatin/IGF-1 feedback modulation of the GHRHR axis.

No. Because it signals through the native GHRH receptor, GH output in model systems remains pulsatile and subject to somatostatin (SSTR) counter-regulation and IGF-1 negative feedback rather than bypassing these control loops. This is why it is described as a tool for probing intact somatotroph regulation.

No. In this reference context it is a research-use-only material. All framing here is strictly in-vitro, receptor-signaling, and laboratory-handling oriented; nothing here describes administration, dosing, or any therapeutic, weight-management, or disease-treatment use.