Sermorelin: GHRH(1-29) Fragment Research Overview

Sermorelin (GHRH 1-29) is the truncated active fragment of the full 44-amino acid endogenous growth hormone-releasing hormone. Research established in the 1980s that the first 29 amino acids retain virtually full receptor binding and signaling activity, making this fragment a practical synthetic alternative to the full-length molecule.^[1]

Sermorelin established the framework that subsequent GHRH analogs (CJC-1295, Tesamorelin) built upon. Both later compounds use GHRH(1-29) as their starting backbone and add stability modifications. Sermorelin itself uses the unmodified human sequence and is therefore the closest synthetic comparator to native GHRH in preclinical studies.^[2]

Sermorelin is studied as a research reference compound. While it has approved clinical indications in specific contexts, research-grade material supplied for laboratory use is intended exclusively for in vitro and educational research applications.

Sermorelin structural specifications:

• Sequence: First 29 amino acids of human GHRH (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)

• Molecular formula: C₁₄₉H₂₄₆N₄₄O₄₂

• Molecular weight: approximately 3,358 Da

• C-terminal amidation: present (NH₂-Arg-NH₂)

• Length: 29 amino acids

Native human GHRH is 44 amino acids long. Truncation studies established that the C-terminal 15 residues (positions 30-44) are dispensable for receptor binding and activation. Sermorelin's 1-29 sequence retains the receptor-binding determinants and the alpha-helical structural propensity needed for productive GHRHR engagement.^[1]

Sermorelin's research activity centers on the GHRH receptor (GHRHR).

Sermorelin binds GHRHR with affinity comparable to native GHRH and activates the canonical cAMP signaling pathway. The receptor is a class B G-protein-coupled receptor expressed primarily on pituitary somatotrophs.^[3]

Unmodified GHRH(1-29) is susceptible to DPP-4 cleavage at the N-terminus, producing a short half-life (on the order of minutes) in research-relevant biological matrices. This contrasts with engineered analogs (Tesamorelin with its N-terminal modification; CJC-1295 with its position-2 D-Ala substitution) that resist DPP-4. The short half-life makes Sermorelin useful for studies of acute GHRH signaling where rapid clearance is preferred.^[4]

Sermorelin literature is extensive given the compound's history in research.

Sermorelin was instrumental in establishing the receptor pharmacology and downstream signaling characteristics of GHRHR activation. Cell-based and pituitary preparation studies using Sermorelin contributed substantially to current understanding of the GHRH axis.^[1][3]

Provocative testing of the somatotropic axis in preclinical models historically used GHRH or its 1-29 fragment (Sermorelin). The compound is a standard tool for evaluating pituitary somatotroph responsiveness in animal studies.^[4]

Modern GHRH analog research (Tesamorelin, CJC-1295) frequently uses Sermorelin as the comparator compound, since its unmodified sequence provides a baseline for assessing the effects of stability-enhancing modifications.^[2][5]

Without stability modifications, Sermorelin is more sensitive to degradation than its engineered analog cousins. Careful handling is important.

Lyophilized Sermorelin is stored at minus 20 degrees Celsius for long-term preservation. Refrigerated storage at 4 degrees Celsius is acceptable short-term. Reconstituted solution has limited stability and is typically used within several weeks.

Bacteriostatic water is the standard reconstitution solvent. Sterile water is also used. Gentle reconstitution (directing solvent down the vial wall, swirling rather than shaking) is important to minimize loss.

Quality verification includes HPLC for purity (greater than or equal to 99 percent), mass spectrometry for identity confirmation, and endotoxin testing. Every batch of Instant Peptides Sermorelin ships with a full Certificate of Analysis.

Instant Peptides supplies Sermorelin as a synthetic lyophilized reference compound. Material is supplied to qualified research professionals and scientific institutions. Not for human or animal consumption, diagnostic, or therapeutic use.

View the product page for current pricing and the Certificate of Analysis for the active batch.