Ghrelin
Ghrelin is the endogenous 28-amino-acid "hunger hormone" secreted directly by gastric oxyntic cells. As the ultimate, natural biological ligand for the Growth Hormone Secretagogue Receptor (GHS-R1a), exogenous Ghrelin is essentially the blueprint from which all synthetic GHRPs (like Ipamorelin or GHRP-6) are derived. In clinical research, it is utilized to rapidly reverse severe cancer-induced cachexia, forcefully restart motility in paralyzed gastroparesis, and trigger massive systemic GH pulses.
Quick Stats
Scientific Data
Mechanism of Action
Ghrelin (the "hunger hormone") is a 28-amino-acid endogenous peptide produced primarily by endocrine cells in the stomach fundus. It requires octanoylation at its 3rd serine residue to become biologically active (acyl-ghrelin).
It works by binding the growth hormone secretagogue receptor 1a (GHS-R1a) in the hypothalamus, triggering two dramatic effects: profound appetite stimulation (orexigenic effect) and potent growth hormone release from the pituitary. Because the actual ghrelin peptide is highly unstable and difficult to synthesize with its required lipid modification, synthetic GHRPs (like GHRP-6, GHRP-2, Ipamorelin) or non-peptides (Macimorelin) are used instead to stimulate the ghrelin receptor therapeutically.
Source: PMID: 10604470
Background & History
Ghrelin was discovered in 1999 by Masayasu Kojima and colleagues in rat stomach. It was the first known endogenous ligand for the growth hormone secretagogue receptor (GHS-R1a), explaining how synthetic secretagogues like GHRP-6 worked. Ghrelin is now recognized as a key regulator of energy homeostasis, connecting gut-brain signaling for appetite, metabolism, and growth hormone release. Its role in cachexia (cancer-related wasting) has driven clinical trials.
Research Use Cases
- ✓Cancer cachexia research
- ✓Gastroparesis
- ✓GH deficiency research
- ✓Anorexia nervosa research
- ✓Post-surgical ileus
Dosing Protocol
| Typical Dose | 1-5 mcg/kg IV (research) |
| Frequency | Per study protocol |
| Half-Life | 0.5 hours |
| Common Vial Sizes | 5 mg |
Dosing Protocols
Reference Only
Body-Weight Dosing Reference
Estimated doses extrapolated from the published research range of 70–350 mcg/day (referenced to 70 kg / 154 lb). These are approximations — consult a qualified healthcare provider for personalised guidance.
| Weight | Low Dose | Target Dose | High Dose |
|---|---|---|---|
| 120 lb(54 kg) | 54 mcg | 162 mcg | 270 mcg |
| 140 lb(63 kg) | 63 mcg | 189 mcg | 315 mcg |
| 160 lb(73 kg) | 73 mcg | 219 mcg | 365 mcg |
| 180 lb(82 kg) | 82 mcg | 246 mcg | 410 mcg |
| 200 lb(91 kg) | 91 mcg | 273 mcg | 455 mcg |
| 220 lb(100 kg) | 100 mcg | 300 mcg | 500 mcg |
| 250 lb(113 kg) | 113 mcg | 339 mcg | 565 mcg |
💉 For exact syringe units based on your vial concentration, use the Ghrelin Reconstitution Calculator →
Administration
Expected Timeline
Who Is It For?
Endogenous Marker
ModerateImportant mechanism for hunger and GH release, targeted by many other pharmacological peptides.
Reconstitution Example
Safety & Considerations
Endogenous hormone. High ghrelin states (Prader-Willi syndrome) cause insatiable hunger. Modulated extensively by fasting, sleep, and medical peptides.
Regulatory & Legal Status
Not currently on the WADA 2026 Prohibited List. Policies may change — verify before competition.
Research Chemical
US Compounding: Not eligible / not available
⚠️ This information is for educational purposes only and may not reflect the most current regulatory updates. Always verify with official FDA, WADA, and jurisdiction-specific sources before use.
Interactions & Contraindications
May increase appetite and food intake. Can cause transient hyperglycemia. Interacts with insulin and leptin signaling pathways. Ghrelin O-acyltransferase (GOAT) inhibitors are being developed as anti-obesity agents.
Synergies & Common Stacks
GHRP-2 is a synthetic ghrelin receptor agonist — ghrelin is the endogenous ligand. They activate the same receptor but ghrelin has additional metabolic effects.
MK-677 is a non-peptide oral ghrelin mimetic. It provides sustained oral GHS-R1a activation that compensates for ghrelin's extremely short half-life.
Dosing Quick Reference
Frequently Asked Questions
Why is native ghrelin not used as a medicine?▼
References
- Kojima M et al. “"Ghrelin is a growth-hormone-releasing acylated peptide from stomach".” Nature (1999). PMID: 10604470
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