Sermorelin

Sermorelin (GHRH 1-29) is a synthetic analog containing the first 29 amino acids of the 44-amino acid human growth hormone-releasing hormone. These N-terminal residues contain the full biological activity of native GHRH, making sermorelin functionally equivalent to the endogenous hormone while being more practical to synthesize.

The compound acts by binding to GHRH receptors on pituitary somatotroph cells, activating adenylate cyclase signaling that culminates in growth hormone synthesis and release. Importantly, sermorelin stimulates GH secretion through the physiological pathway, preserving the natural pulsatile pattern and feedback regulation that direct GH administration disrupts.

Sermorelin was the first GHRH analog approved for clinical use and remains a reference compound in GH research. Its relatively short plasma half-life (10-20 minutes) means it produces acute GH pulses rather than sustained elevation, which more closely mimics physiological secretion patterns but requires multiple daily administrations.

Research applications include diagnostic assessment of pituitary GH reserve, studies of age-related GH decline, and investigation of GHRH receptor function. Sermorelin serves as a comparator compound for evaluating extended-release GHRH analogs like CJC-1295 and is often studied in combination with GH secretagogues to characterize synergistic release mechanisms.