Secretagogue
Also known as: Growth hormone secretagogue, GHS, Secretagog
Secretagogue is a substance that promotes the secretion of another substance from a cell or gland. In peptide research, secretagogues typically refer to compounds that stimulate the release of hormones like growth hormone, insulin, or other signaling molecules without providing the hormone directly.
Last updated: January 21, 2026
How Secretagogues Work
Secretagogues stimulate hormone release through receptor activation:
- Binding - Secretagogue binds to specific receptor
- Signal cascade - Triggers intracellular signaling
- Hormone release - Target gland secretes its hormone
- Physiological effect - Released hormone acts on tissues
Types of Growth Hormone Secretagogues
GHRH-Based Secretagogues
Work through the GHRH receptor on pituitary cells:
- Sermorelin - GHRH (1-29) fragment
- CJC-1295 - Modified GHRH with extended half-life
- Tesamorelin - FDA-approved GHRH analog
Ghrelin Mimetics
Work through the ghrelin receptor (GHS-R):
- Ipamorelin - Selective pentapeptide
- GHRP-6 - Hexapeptide secretagogue
- GHRP-2 - More potent than GHRP-6
- MK-677 - Non-peptide oral secretagogue
Secretagogue vs Direct Hormone
| Characteristic | Secretagogue | Direct Hormone |
|---|---|---|
| Mechanism | Stimulates natural release | Provides exogenous hormone |
| Pulsatility | Maintains natural patterns | May override patterns |
| Feedback loops | Generally preserved | May be suppressed |
| Production | Still requires functional gland | Bypasses gland entirely |
Selectivity in Secretagogues
Different secretagogues have varying selectivity profiles:
Ipamorelin (Highly Selective)
- Primarily affects GH release
- Minimal effects on cortisol, prolactin
- Considered “clean” GH secretagogue
GHRP-6 (Less Selective)
- Strong GH release
- Also increases cortisol slightly
- Stimulates appetite (ghrelin effect)
GHRP-2 (Moderate Selectivity)
- Potent GH release
- Some cortisol and prolactin effects
- Less appetite stimulation than GHRP-6
Combination Approaches
Researchers sometimes study secretagogue combinations:
GHRH + Ghrelin Mimetic
- CJC-1295 + Ipamorelin studied together
- Different mechanisms may be synergistic
- GHRH amplifies, ghrelin initiates release
Frequently Asked Questions
Why use a secretagogue instead of the hormone itself?
Secretagogues stimulate natural hormone production while maintaining the body’s regulatory feedback systems. This may produce more physiological hormone patterns and potentially fewer side effects than providing the hormone directly.
Do secretagogues work if the gland is damaged?
No. Secretagogues require a functional gland to stimulate. If the pituitary can’t produce growth hormone (due to damage or disease), GH secretagogues won’t be effective. Direct hormone replacement would be needed in such cases.
Are all GH secretagogues peptides?
No. While many are peptides (ipamorelin, GHRP-6), some are non-peptide molecules. MK-677 (ibutamoren) is an example of a non-peptide GH secretagogue that can be taken orally.
Related Peptides
Related Terms
Disclaimer: This glossary entry is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider for medical questions.