Sermorelin 5mg,
Native GHRH(1-29)
The Parent Truncated Growth Hormone-Releasing Hormone
Introduction
The Parent Truncated Growth Hormone-Releasing Hormone
Sermorelin is a synthetic peptide identical in sequence to the first 29 amino acids of native human growth hormone-releasing hormone, the biologically active region of the full-length GHRH(1-44). It is the parent compound from which CJC-1295, tesamorelin, and most modern GHRH analogs have been engineered.
The development of sermorelin in the early 1980s by Ling, Esch, and colleagues represented a foundational achievement in GHRH research. Following the 1982 characterisation of pancreatic tumor-derived GHRH by Guillemin and colleagues, systematic structure-activity studies established that the biologically active portion of the 44-residue native peptide resides in the N-terminal region. Subsequent work narrowed the active region to the first 29 residues, leading to the development of GHRH(1-29), sermorelin, as a synthetic peptide that retains essentially full agonist potency at the GHRH receptor in a more practical 29-residue format.
Sermorelin carries no stabilising substitutions and no protective modifications relative to the native sequence. Its serum half-life is therefore short, approximately 10 to 20 minutes, limited by the same enzymatic and renal clearance mechanisms that inactivate native GHRH. This kinetic profile makes sermorelin well-suited to research designs that require pulsatile GHRH signalling that mimics physiological release patterns, but limits its use in sustained-exposure research applications.
Despite the development of more stable analogs (CJC-1295, tesamorelin), sermorelin remains a critical reference compound in GHRH research because it represents the native human sequence. Comparative studies that aim to characterise how specific stabilising modifications alter pharmacological profile relative to the native peptide use sermorelin as the necessary baseline.
Molecular Architecture
The Active Region of Native GHRH
Sermorelin's sequence is identical to the first 29 amino acids of native human growth hormone-releasing hormone. The fact that this 29-residue fragment retains essentially full agonist potency at the GHRH receptor, even though the full native peptide is 44 residues long, illustrates a recurring theme in class B GPCR pharmacology: that the N-terminal region of the ligand carries the principal receptor-activation determinants.
The sermorelin sequence (H-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) carries the C-terminal amidation characteristic of native GHRH, which is required for full receptor activation. The N-terminal Tyr1 residue is critical for receptor binding, and the Ala2 residue is the cleavage site for dipeptidyl peptidase-IV (DPP-IV), the enzymatic step that inactivates native GHRH within minutes by producing the inactive GHRH(3-29) fragment.
Mechanistically, sermorelin engages the GHRH receptor (GHRHR), a class B G protein-coupled receptor expressed on anterior pituitary somatotroph cells. Receptor activation drives Gαs-mediated cAMP accumulation, PKA-dependent phosphorylation of CREB, and downstream transcription of growth hormone (GH1) and the pituitary-specific transcription factor Pit-1. Sermorelin's cAMP accumulation EC50 in cell-based assays matches that of native GHRH(1-44), confirming that the truncated peptide retains full agonist potency.
The principal pharmacokinetic limitation of sermorelin is its rapid degradation. DPP-IV cleaves the Tyr1-Ala2 bond within minutes, producing the inactive metabolite. Methionine at position 27 is susceptible to oxidation during storage. Multiple endopeptidases in serum and tissues further contribute to the short half-life. These limitations motivated the development of stabilised analogs including CJC-1295 (no DAC), which addresses each of these vulnerabilities through specific substitutions.
Research Applications
Native-Sequence GHRH Pharmacology
Sermorelin's position as the native-sequence GHRH research compound makes it the necessary baseline for comparative pharmacology studies and a primary tool for research designs that require physiological pulsatile signalling.
In receptor pharmacology, sermorelin is used as the native-sequence reference for GHRH receptor binding kinetics, cAMP signalling, and downstream gene expression. Comparative work with stabilised analogs (CJC-1295 (no DAC), tesamorelin, and the long-acting CJC-1295/DAC variant) uses sermorelin as the baseline against which the pharmacological effects of specific substitutions and modifications are measured. These comparisons are essential to characterising how engineering choices translate into pharmacological differences.
Pulsatile-release research designs use sermorelin to mimic the physiological pattern of native GHRH secretion. The short circulating half-life makes the compound particularly suited to research that aims to characterise pulsatile signalling at the somatotroph cell level, including studies of receptor desensitisation, GH vesicle replenishment kinetics, and integrated regulation by somatostatin tone.
Pituitary transcriptomic research uses sermorelin to characterise the native-sequence transcriptional response in somatotroph cells. Published microarray and RNA-seq studies document effects on growth hormone (GH1), Pit-1, and downstream IGF-1 axis genes. These studies inform broader understanding of integrated GH-axis regulation and provide the baseline against which stabilised-analog transcriptomic profiles are measured.
Research Overview
Understanding Sermorelin
Sermorelin is a synthetic peptide identical in sequence to the first 29 amino acids of native human growth hormone-releasing hormone (GHRH). It was developed in the early 1980s by Ling, Esch, and colleagues following the 1982 characterisation of pancreatic tumor-derived GHRH by Guillemin and colleagues. Sermorelin established the foundational principle that the biologically active region of native GHRH resides within the first 29 residues, providing a more practical 29-residue research compound while preserving essentially full agonist potency at the GHRH receptor.
Native human GHRH is a 44-residue hypothalamic peptide that signals through the GHRH receptor (GHRHR), a class B G protein-coupled receptor expressed on anterior pituitary somatotroph cells, to stimulate growth hormone (GH) biosynthesis and secretion. Structure-activity studies in the early 1980s, following the initial discovery of GHRH, established that the C-terminal residues (30-44) are largely dispensable for receptor activation, and that the first 29 residues retain the full biological activity of the parent peptide.
Sermorelin carries no stabilising substitutions or protective modifications relative to the native human sequence. Its serum half-life is therefore short, approximately 10 to 20 minutes, limited by the same enzymatic and renal clearance mechanisms that inactivate native GHRH. Dipeptidyl peptidase-IV (DPP-IV) cleaves the Tyr1-Ala2 bond within minutes, producing the inactive GHRH(3-29) fragment. Methionine at position 27 is also susceptible to oxidation during storage. Multiple endopeptidases in serum and tissues further contribute to the short half-life.
Despite these limitations, sermorelin remains a critical reference compound in GHRH research. Its identity to the native human sequence makes it the necessary baseline for comparative pharmacology studies that aim to characterise how specific stabilising substitutions or modifications alter the pharmacological profile of GHRH analogs. Comparative work with CJC-1295 (no DAC) (which carries four stabilising substitutions), tesamorelin (which carries an N-terminal hexenoyl modification), and the long-acting CJC-1295/DAC variant (which carries an albumin-linker moiety) uses sermorelin as the baseline against which the effects of engineering choices are measured.
Receptor pharmacology characterisation has been extensive. Sermorelin binds the GHRH receptor with affinity comparable to native GHRH(1-44) and produces cAMP accumulation profiles that match the native peptide. The receptor is coupled primarily to Gαs and activates the canonical cAMP/PKA signalling cascade, leading to phosphorylation of CREB and subsequent transcription of growth hormone (GH1) and the pituitary-specific transcription factor Pit-1.
Pulsatile-release research designs use sermorelin to mimic the physiological pattern of native GHRH secretion, which occurs in discrete pulses across the day with major pulses during slow-wave sleep. The short circulating half-life of sermorelin is well-suited to research that aims to characterise pulsatile signalling at the somatotroph cell level, including studies of receptor desensitisation, GH vesicle replenishment kinetics, and integrated regulation by somatostatin tone. Combination research with GHRP-class compounds, particularly ipamorelin, also uses sermorelin as the GHRH-side component in certain protocols.
Within the broader landscape of GHRH analog research, sermorelin occupies a unique and irreplaceable position. It is the only research compound identical to native human GHRH in the active 29-residue region, making it the necessary baseline for understanding how the stabilised analogs differ pharmacologically from the natural peptide. Researchers continue to use sermorelin as a reference compound in GHRH receptor pharmacology, in pulsatile-release research designs, and in comparative pharmacology work across the broader GHRH analog class.
Selected Literature
Peer-reviewed publications cited in this overview
- [1] Thorner MO, et al. Growth hormone-releasing hormone: from clinical studies to clinical application. J Clin Endocrinol Metab. 1990;71(5):1115-1123.
- [2] Ling N, et al. Synthesis and in vitro bioactivity of C-terminal deleted analogs of human growth hormone-releasing factor. Biochem Biophys Res Commun. 1984;123(3):854-861.
- [3] Guillemin R, et al. Growth hormone-releasing factor from a human pancreatic tumor that caused acromegaly. Science. 1982;218(4572):585-587.
- [4] Walker RF. Sermorelin: a better approach to management of adult-onset growth hormone insufficiency? Clin Interv Aging. 2006;1(4):307-308.
- [5] Sinha DK, et al. Beyond the androgen receptor: the role of growth hormone secretagogues. Asian J Androl. 2020;22(1):14-19.
Samir K. –
Sermorelin from Anglo is really good quality. Came packaged well, shipped fast. Clean powder, dissolved easily. Anglo is now my first stop for Canadian peptides.
Lisa F. –
Ordered sermorelin and was impressed with the speed. Had it in two days. Reconstituted perfectly, no cloudiness. Really solid source.
Greg N. –
Arrived well packaged, dissolved clean. Anglo\’s been reliable across a few orders now. Fair price for sermorelin in Canada and the shipping speed is hard to beat.
Adrian N. –
Sermorelin from Anglo Peptides is outstanding. Canadian-made and Janoshik-tested at 99%+. Reconstitutes instantly to a clear solution. Sixth order now. This is my permanent source.
Stella V. –
Consistent quality every single time I order. Same-day Xpresspost, arrives cold-packed in perfect condition. The Canadian-made aspect makes a real difference for my research.
Finn L. –
Great Sermorelin, arrived quickly to Calgary. Good documentation with a batch-specific Janoshik COA. The reconstitution was clean. Will definitely buy again from Anglo.
Catherine P. –
Good quality Sermorelin at a fair price for Canadian researchers. Vial was intact and well-sealed. COA is linked on the product page. Panda ships fast and the e-Transfer process is seamless.
Lucas B. –
Third time ordering Sermorelin from Anglo. Quality is consistent, same-day shipping when you hit the cutoff, and the product page documentation is thorough. Best Canadian source I have found.
Anna R. –
Sermorelin arrived well within the week to Quebec. Lyophilized properly, sealed correctly, and the Kraus COA gives me confidence. Will keep ordering from Anglo Peptides.