Sermorelin — Canada Research Brief

Origin and rationale

Sermorelin traces directly to the isolation of growth hormone-releasing hormone by Guillemin, Rivier and colleagues in 1981–1982, working from pancreatic tumour extracts that produced ectopic acromegaly. Once the full 44-residue GHRH sequence was resolved, structure–activity work quickly established that the N-terminal 29 residues — GRF(1-29) — retained the full biological activity of the parent hormone at the pituitary GHRH receptor. That fragment, synthesised with a C-terminal amide, became sermorelin.

Mechanistically, sermorelin binds the GHRH receptor on pituitary somatotrophs and drives pulsatile growth hormone release in a pattern consistent with endogenous GH rhythm, preserving somatostatin feedback — a distinction from exogenous recombinant GH. Its plasma half-life is short, on the order of 10–20 minutes, because native GHRH(1-29) is rapidly cleaved at the Ala²–Asp³ bond by dipeptidyl peptidase-IV.

Regulatory history

Sermorelin was developed clinically by Serono and approved by the FDA as Geref for the diagnosis of growth hormone deficiency, and subsequently for the treatment of idiopathic GH deficiency in children. Serono voluntarily discontinued Geref in 2008. The withdrawal was a commercial decision — not a safety action — and sermorelin continued to be prepared by U.S. compounding pharmacies in the years that followed. Sermorelin has no current Health Canada authorisation and is not available as an approved drug product in Canada; it is handled as a research chemical only.

Comparison to CJC-1295

Sermorelin and CJC-1295 sit on the same pharmacological axis but at opposite ends of the half-life spectrum. Sermorelin is the unmodified native GRF(1-29) sequence and is cleared within minutes. CJC-1295 "no-DAC" — functionally equivalent to Modified GRF(1-29) — adds four substitutions (D-Ala², Gln⁸, Ala¹⁵, Leu²⁷) that resist DPP-IV degradation and extend the half-life to roughly 30 minutes while preserving a pulsatile GH release pattern. CJC-1295-DAC further appends a maleimidopropionyl lysine linker that binds covalently to albumin, turning the peptide into an albumin-conjugated prodrug with a half-life of 6–8 days and sustained IGF-1 elevation. Researchers select sermorelin when a short, physiological pulse is wanted; CJC-1295-DAC when sustained GH-axis stimulation is the experimental endpoint.

Storage

Store lyophilised sermorelin at −20°C protected from light. Reconstituted peptide is stable refrigerated at 2–8°C for 2–4 weeks. Avoid repeated freeze-thaw cycles.