SERMORELIN: 10 mg ($45)
Overview
Sermorelin is a laboratory-synthesized fragment of a naturally occurring signaling molecule that tells the pituitary gland to release more growth hormone. Because it is cleared from the blood within minutes, the signal it produces is much shorter than that of a longer-acting analogue such as Tesamorelin — closer to the brief pulses the body generates on its own. The resulting rise in growth hormone is correspondingly smaller than with the longer-acting analogue.
In plain terms
The body regulates many of its processes through a chain of command. The hypothalamus, a small structure at the base of the brain, sends a chemical message to the pituitary gland just below it. The pituitary receives that message and responds by releasing a hormone of its own into the bloodstream. GHRH is one of those messages, and growth hormone is the response it triggers.
Sermorelin is a copy of that message. Because it is a shortened version retaining the part the receptor actually recognizes, it binds the same site on pituitary cells that natural GHRH does. What makes it scientifically interesting is that it acts on a system with its own regulatory brakes — the pituitary's response is still governed by somatostatin, an opposing signal that suppresses release. The pathway does not simply run in one direction when stimulated, and that behavior is much of what makes the molecule useful to study.
Technical description
Sermorelin (GRF 1–29 NH2) is a 29-amino-acid peptide corresponding to the N-terminal fragment of endogenous human GHRH(1–44). It functions as an agonist at the growth hormone-releasing hormone receptor (GHRHR), a class B GPCR expressed on pituitary somatotroph cells.
Receptor binding activates adenylyl cyclase via Gs, raising intracellular cAMP and activating protein kinase A, which drives both release of stored somatotropin and transcriptional upregulation of the GH1 gene. Because the mechanism is receptor-mediated and upstream, secretion remains subject to negative feedback from somatostatin and circulating IGF-1. Plasma half-life is short, on the order of 10–20 minutes, reflecting rapid proteolytic clearance.
- Full name
- Growth hormone-releasing factor (1–29) amide
- Synonyms
- GRF 1–29, GHRH(1–29) NH2
- CAS number
- 86168-78-7
- Molecular formula
- C149H246N44O42S
- Molecular weight
- 3357.9 g/mol
- Sequence
- YADAIFTNSYRKVLGQLSARKLLQDIMSR-NH2
- Receptor target
- GHRHR (class B GPCR)
- Appearance
- White lyophilized powder
- Storage
- Lyophilized: −20 °C, protected from light. Reconstituted: 2–8 °C.
Regulatory status
Sermorelin was previously marketed in the United States as a prescription pharmaceutical under the brand name Geref, withdrawn from the U.S. market in 2008 for commercial rather than safety reasons. It is not currently an FDA-approved product and is not a dietary supplement. Material supplied for laboratory research is not manufactured, tested, or released under pharmaceutical standards.