Interested in this peptide?
Request more information and our team will get back to you within 2 business days.
What Is Sermorelin?
Sermorelin (also known as GRF 1-29 or GHRH 1-29) is a synthetic peptide consisting of the first 29 amino acids of the 44-amino acid human growth hormone-releasing hormone (GHRH). This truncated sequence retains full biological activity, as the first 29 amino acids contain all the information needed for GHRH receptor binding and activation.
Sermorelin was the first GHRH analog to receive FDA approval (1997) for diagnosis and treatment of GH deficiency in children. Though the branded versions have been discontinued, it remains an important reference compound.
Key Characteristics
- History: FDA approved 1997 (now discontinued as branded drug)
- Structure: First 29 amino acids of natural GHRH
- Half-life: Very short (~10-20 minutes)
- Mechanism: GHRH receptor agonist
Historical Significance
Sermorelin holds an important place in peptide history:
- First synthetic GHRH analog to be FDA approved
- Proved the concept of stimulating endogenous GH release
- Established safety profile for GHRH-class peptides
- Led to development of more advanced analogs (CJC-1295, tesamorelin)
Mechanism of Action
GHRH Receptor Activation
Sermorelin works identically to natural GHRH:
- Binds to GHRH receptors on pituitary somatotroph cells
- Activates adenylyl cyclase → increases cAMP
- Triggers GH synthesis and secretion
- Stimulates both release and production of GH
Physiological Advantages
- Maintains natural pulsatile GH secretion pattern
- Works with intact negative feedback mechanisms
- Does not suppress endogenous GHRH production
- Cannot cause GH excess (pituitary-limited)
Limitations
- Very short half-life requires frequent administration
- Susceptible to enzymatic degradation
- Requires functional pituitary gland
- Response diminishes with severe GH deficiency
Clinical Research and Applications
Approved Indications (Historical)
- Diagnostic: Testing pituitary GH secretion capacity
- Therapeutic: Treatment of GH deficiency in children
- Branded products discontinued for commercial (not safety) reasons
Research in Adults
Extensive research has examined sermorelin in adults:
- Age-related GH decline (somatopause)
- Body composition changes with aging
- Sleep quality improvements
- Cognitive function studies
Sleep and GH Secretion
Research on sermorelin and sleep:
- GH is naturally released during deep sleep
- Evening sermorelin may enhance sleep-related GH release
- Some studies show improved sleep quality
- Mechanism may involve restoration of natural GH rhythm
Key Published Research
| Year | Focus | Key Finding | Reference |
|---|---|---|---|
| 1990 | Pediatric GH deficiency | Effective in stimulating growth | Thorner et al. |
| 1998 | Adult aging | Improved body composition | Vittone et al. |
| 2001 | Sleep | Enhanced slow-wave sleep | Copinschi et al. |
| 2003 | Long-term use | Sustained efficacy over 2 years | Khorram et al. |
Sermorelin vs Other GHRH Analogs
| Peptide | Length | Half-life | Status |
|---|---|---|---|
| Sermorelin | 29 aa | 10-20 min | Previously FDA approved |
| Mod GRF (1-29) | 29 aa | ~30 min | Research compound |
| CJC-1295 DAC | 30 aa + DAC | 6-8 days | Research compound |
| Tesamorelin | 44 aa + mod | ~30 min | FDA approved |
Evolution to Modified GRF (1-29)
From Sermorelin to Mod GRF
To address sermorelin's short half-life, researchers developed Modified GRF (1-29):
- Same 29 amino acids as sermorelin
- Four amino acid substitutions (positions 2, 8, 15, 27)
- Resistant to enzymatic breakdown (DPP-IV)
- Half-life extended to ~30 minutes
- Also called CJC-1295 without DAC or "Mod GRF"
Administration
Historical and research protocols:
- Route: Subcutaneous or intravenous injection
- Timing: Often at bedtime to enhance natural GH pulse
- Frequency: Daily (due to short half-life)
- Duration: Months to years in clinical use
Safety Profile
Based on FDA approval and clinical experience:
- Generally well-tolerated
- Most common: injection site reactions
- Possible flushing, dizziness, headache
- Cannot cause GH excess (pituitary is rate-limiting)
- Long-term safety data available from clinical use
Current Status
While sermorelin was previously FDA-approved, branded versions (Geref/Gerel) have been discontinued. It remains available as a compounded medication through some pharmacies and as a research compound. Newer GHRH analogs with improved stability (tesamorelin, CJC-1295) have largely superseded it in both clinical and research settings.
Summary
Sermorelin represents the foundational GHRH analog that established the concept of stimulating endogenous GH release. Its FDA approval provided valuable safety and efficacy data for the entire class. While its short half-life has led to development of improved analogs, sermorelin's mechanism of action and clinical history remain important references for understanding GHRH-based therapies.