A 29-amino-acid peptide corresponding to the first 29 residues of natural GHRH (1-44). The shortest fragment that retains full biological activity. FDA-approved as a diagnostic agent for GH deficiency and formerly approved for GH-deficient children.
Sermorelin (GHRH 1-29) is a 29-amino-acid peptide that is the biologically active fragment of the 44-amino-acid growth hormone-releasing hormone. It was the first GHRH-based therapeutic developed, demonstrating that only the first 29 residues are needed for full GHRH receptor activation.
Unlike exogenous GH injection, sermorelin stimulates the pituitary to produce and release its own GH through the natural GHRH receptor pathway. This preserves the physiological pulsatile pattern of GH secretion and allows the body's feedback mechanisms to prevent excess GH levels.
Sermorelin is the prototypical GHRH receptor agonist. It activates the same Gs-cAMP-PKA cascade as native GHRH, stimulating both GH gene transcription and release of stored GH granules from somatotrophs.
| Pathway | Effect | Significance |
|---|---|---|
| GHRH-R agonism | Full activation of GHRH receptor with first 29 residues | Identical signaling to native GHRH 1-44 |
| Pulsatile GH | Short half-life produces natural GH pulses | Preserves physiological GH secretion pattern |
| IGF-1 stimulation | GH-mediated hepatic IGF-1 production | Downstream growth, repair, and metabolic effects |
| No GH suppression | Works through natural axis, not exogenous replacement | Body's feedback prevents excess GH |
| Study | Design | Findings | Level |
|---|---|---|---|
| GH deficiency diagnosis | FDA-approved diagnostic | IV sermorelin measures pituitary GH reserve. Normal response rules out pituitary cause of GH deficiency. | Level I |
| Pediatric GH deficiency | Former FDA indication | Stimulated growth in GH-deficient children. Withdrawn from market (2008) for commercial reasons, not safety. | Level I |
| Anti-aging | Clinical studies | Increased IGF-1, improved body composition, sleep quality in adults. Off-label use common. | Level II-III |
Well-tolerated: Injection site reactions, facial flushing, headache most common. Generally mild.
Short duration: Requires daily injection due to short half-life. Less convenient than CJC-1295.
| Jurisdiction | Status |
|---|---|
| FDA | Approved as diagnostic (Geref). Former therapeutic approval withdrawn 2008 (commercial, not safety). |
| WADA | Banned under S2 |
| Status | Largely replaced by CJC-1295 and tesamorelin in clinical use |
| Feature | Sermorelin | CJC-1295 |
|---|---|---|
| Length | 29 amino acids | 30 amino acids |
| Half-life | 10-20 minutes | 6-8 days (with DAC) |
| Dosing | Daily injection | Weekly injection |
| Modification | None (natural sequence) | DAC for albumin binding |
| FDA status | Approved (diagnostic) | Not approved |