GHRP-6
Medium EvidenceA growth hormone secretagogue that also stimulates appetite through ghrelin receptor activation.
What It Is
GHRP-6 (Growth Hormone Releasing Peptide-6) is a synthetic hexapeptide that stimulates growth hormone secretion by binding to the ghrelin receptor (GHS-R1a) in the hypothalamus and pituitary gland. It is one of the earliest discovered GH secretagogues and remains widely referenced in growth hormone research. Unlike more selective peptides such as ipamorelin, GHRP-6 also stimulates cortisol, prolactin, and notably appetite — the latter mediated through its ghrelin-mimetic activity. Clinical studies have confirmed robust, dose-dependent GH release, with peak GH levels occurring approximately 15–30 minutes after subcutaneous administration. The strong appetite-stimulating effect, while undesirable for fat-loss applications, has been studied for potential therapeutic use in cachexia and age-related appetite decline. GHRP-6 remains on the FDA's Category 2 list as of May 2026 and is expected to stay restricted, meaning it cannot be legally compounded by 503A or 503B pharmacies in the United States. It is listed by WADA as a prohibited substance in competitive sports. GHRP-6 is not FDA-approved for any indication.
Why Researchers Study It
GHRP-6 was one of the first synthetic GH secretagogues identified and remains a reference compound for studying ghrelin receptor pharmacology. Its pronounced appetite-stimulating effect, mediated through the same ghrelin receptor pathway, makes it a useful tool for investigating the intersection of growth hormone release and hunger signaling.
Proposed Mechanisms
- Binds the growth hormone secretagogue receptor (GHS-R1a, the ghrelin receptor) to trigger pulsatile GH release
- Stimulates appetite via hypothalamic ghrelin signaling pathways
- May elevate cortisol and prolactin through non-selective receptor activation
- Amplifies GH release synergistically when paired with GHRH analogs like CJC-1295
Evidence Snapshot
| Study Type | Model | Outcome | Link |
|---|---|---|---|
| Human | GH secretion studies in healthy adults | Dose-dependent GH release with concurrent appetite stimulation | Source |
Commonly Discussed Benefits
Safety & Cautions
- Significantly increases appetite, which may be undesirable
- May elevate cortisol and prolactin levels
- Less selective than newer GH secretagogues like ipamorelin
- Not FDA-approved
Comparisons
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Citations
- [1] Bowers CY. — Growth hormone-releasing peptide (GHRP). Cell Mol Life Sci. 1998 PubMed
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Related Peptides
CJC-1295
Medium EvidenceA growth hormone releasing hormone analog studied for stimulating growth hormone secretion.
Ipamorelin
Medium EvidenceA selective growth hormone secretagogue studied for targeted GH release with fewer side effects than other GH peptides.
Sermorelin
Medium EvidenceA GHRH analog previously FDA-approved for growth hormone deficiency diagnosis and treatment.