Research guide

Sermorelin

Synthetic native GHRH(1-29) — the minimal active fragment of endogenous GHRH retaining full GHRHR agonist activity. Used as the reference standard for pituitary somatotroph studies and as a DPP-IV-susceptible comparator to modified GHRH analogues.

By HALO Editorial · Reviewed May 24, 2026 · Editorial standards

Short answer

Sermorelin is supplied by HALO as a research-use-only lyophilized compound for qualified laboratory research. Synthetic native GHRH(1-29) — the minimal active fragment of endogenous GHRH retaining full GHRHR agonist activity. Used as the reference standard for pituitary somatotroph studies and as a DPP-IV-susceptible comparator to modified GHRH analogues.

Molecular weight: 3,357.9 g/mol
CAS: 86168-78-7
Available sizes: 2 mg · 5 mg · 10 mg
Documentation: 98%+ HPLC purity, independent COA, lot-indexed records
Use limitation: Research use only; not for human or veterinary use

Diagrams

Research pathway context (schematic)

Identity card

COA verification flow

Lyophilized handling workflow

Mechanism of action in research models

GHRHR agonism and cAMP signalling: Sermorelin binds the GHRH receptor on pituitary somatotroph cells — a class-B (secretin family) Gs-coupled GPCR — with high affinity, activating adenylyl cyclase and generating cAMP. Elevated cAMP activates PKA, which phosphorylates voltage-dependent K⁺ channels, prolongs action potentials, and triggers Ca²⁺ influx through L-type calcium channels, culminating in GH-granule exocytosis. PKA also activates CREB to stimulate GH gene transcription.

Pit-1 / GHF-1 activation: through CREB and PKA, GHRHR stimulation activates the pituitary-specific transcription factor Pit-1/GHF-1, controlling transcription of GH, PRL, and GHRHR genes — enabling research into how GHRH signalling regulates long-term somatotroph identity beyond acute GH release.

DPP-IV metabolism research: because Sermorelin retains the native Ala2-Asp3 DPP-IV cleavage site, it is used as a positive control in research examining the pharmacokinetics of DPP-IV inhibition on GHRH-analogue stability. Researchers compare Sermorelin (rapid DPP-IV degradation) vs CJC-1295 No DAC (DPP-IV-resistant) to measure DPP-IV’s quantitative contribution to GHRH inactivation.

Somatostatin interaction: Sermorelin is used in studies examining how somatostatin (SRIF) tone modulates the GH-pulse amplitude response to GHRH stimulation — Sermorelin serving as a controlled pulse-like GHRHR activator.

Research background and peer-reviewed literature

GHRH and its active fragments were characterised by the Guillemin laboratory at the Salk Institute and the Vale/Rivier laboratory in 1982. Both groups demonstrated that the N-terminal 29-amino-acid fragment retained full biological activity. Thorner et al. published pioneering studies establishing dose-response relationships and pulsatility parameters of synthetic GHRH(1-29). In ageing research, Corpas et al. demonstrated that Sermorelin-based GHRH administration could restore GH pulse amplitude and partially reverse age-related decrements in GH and IGF-1.

Reconstitution and storage protocol

Equilibrate vial to room temperature before opening.
Reconstitute in bacteriostatic water; Sermorelin is readily water-soluble. Typical concentration: 1 mg/mL.
Add diluent slowly along the vial wall; swirl gently to dissolve.
For cell culture: filter through 0.22 μm.

Storage: lyophilized at −20 °C, sealed, desiccated, light-protected (stable 24+ months). Reconstituted at 4 °C for up to 28 days; aliquot at −80 °C for extended storage.

Frequently asked research questions

How does Sermorelin differ from CJC-1295 No DAC?

Sermorelin is the native GHRH(1-29) sequence. CJC-1295 No DAC is a modified version with four amino-acid substitutions conferring DPP-IV resistance and longer plasma half-life (~30 min vs ~7 min for Sermorelin). Sermorelin is used as a reference standard with native pharmacokinetics; CJC-1295 No DAC is preferred when a longer research window is required. Comparing them in the same experiment quantifies DPP-IV’s contribution to GHRH inactivation.

What intracellular pathway does Sermorelin activate?

Sermorelin activates GHRHR (Gs-coupled class-B GPCR), generating cAMP via adenylyl cyclase. cAMP activates PKA, which: (1) phosphorylates voltage-gated K⁺ channels (prolonging depolarisation and Ca²⁺ influx for GH exocytosis); (2) activates CREB (GH gene transcription); (3) activates Pit-1/GHF-1 (long-term somatotroph gene expression). The result is acute GH secretion plus chronic priming of secretory capacity.

Can Sermorelin be combined with Ipamorelin?

Yes — a classical experiment in GH-axis research. Sermorelin activates GHRHR (Gs-cAMP pathway, GH-gene-expression priming) while Ipamorelin activates GHSR-1a (Gq-Ca²⁺ pathway, direct exocytosis trigger). The two pathways are synergistic, producing larger GH-pulse amplitudes than either agonist alone. The shorter Sermorelin half-life makes the timing of acute experiments more precisely controllable.

Why does Sermorelin have a shorter half-life than CJC-1295?

Sermorelin retains the native Ala2-Asp3 dipeptide bond at the N-terminus, efficiently cleaved by DPP-IV (a serine protease in plasma, kidney brush border, and capillary endothelium). This cleavage releases an inactive C-terminal fragment. CJC-1295 No DAC substitutes position 2 with Aib (α-aminoisobutyric acid), which cannot be cleaved by DPP-IV, dramatically extending half-life.

Selected references

Guillemin R, et al. “Growth hormone-releasing factor from a human pancreatic tumor.” Science. 1982;218(4572):585-587. PMID: 6812220
Thorner MO, et al. “Physiological and clinical studies of GRF and GH.” Recent Prog Horm Res. 1986;42:589-640. PMID: 3103823
Corpas E, et al. “Human growth hormone and human aging.” Endocr Rev. 1993;14(1):20-39. PMID: 8491146
Frohman LA, Jansson JO. “Growth hormone-releasing hormone.” Endocr Rev. 1986;7(3):223-253. PMID: 2874901

Research use only. Materials are sold strictly for in vitro and qualified laboratory research. Not for human or veterinary use, diagnosis, or treatment. Full text: Research Use Statement.