GHRP-6 Evidence Guide
Evidence for GHRP-6 is too preliminary to support a research protocol with confidence for most applications. The compound raises cortisol and prolactin significantly alongside GH, which complicates interpretation and limits practical utility. Of the Growth Hormone secretagogues in this library, ipamorelin or MK-677 are better-evidenced starting points with cleaner side-effect profiles.
Our Take
Evidence for GHRP-6 is too preliminary to support a research protocol with confidence for most applications. The compound raises cortisol and prolactin significantly alongside GH, which complicates interpretation and limits practical utility. Of the Growth Hormone secretagogues in this library, ipamorelin or MK-677 are better-evidenced starting points with cleaner side-effect profiles.
- Best for
- Older GHRP receptor pharmacology research, appetite stimulation mechanistic studies
- Evidence grade
- Level C
- Confidence
- Low
- Starting point
- 100mcg subcutaneous, up to three times daily - but ipamorelin is preferred for cleaner GH stimulation
Benefits and Evidence
- Growth Hormone Release: Level C, includes human evidence - Robust GH release demonstrated in numerous studies, with peak levels occurring 15-30 minutes post-injection. Less selective than newer GHRPs.
- Appetite Stimulation: Level B, includes human evidence - Pronounced appetite increase via ghrelin receptor activation, often considered the most orexigenic of the GHRPs. Can lead to undesired weight gain.
- Gastric Motility: Level C, includes human evidence - Enhances gastric motility and emptying through ghrelin-like effects on the gastrointestinal tract, investigated as a potential prokinetic agent.
Side Effects and Warnings
- Intense hunger
- Cortisol elevation
- Prolactin elevation
- Water retention
- Flushing
- Dizziness
- Tingling
- Not approved for clinical use in any jurisdiction
Research Dosage References
- <strong>Subcutaneous injection</strong> - 100-300 mcg - 2-3 times daily - Typically administered 30 minutes before meals. Appetite stimulation peaks at 20-30 minutes.
- <strong>Intravenous</strong> - 1 mcg/kg - Single dose (research/diagnostic) - Used in GH stimulation tests. Peak GH response at 15-30 minutes.
Mechanism of Action
GHRP-6 activates the growth hormone secretagogue receptor 1a (GHSR1a), a G-protein coupled receptor primarily expressed in the hypothalamus and pituitary gland. Receptor activation triggers the phospholipase C pathway, leading to inositol triphosphate-mediated calcium release from intracellular stores in somatotroph cells, which drives GH exocytosis. In addition to direct pituitary action, GHRP-6 acts at the hypothalamic level to stimulate GHRH neurons and suppress somatostatin tone, creating a permissive environment for amplified GH release. This hypothalamic action synergizes with direct pituitary stimulation. GHRP-6 also strongly activates orexigenic (appetite-promoting) pathways in the arcuate nucleus of the hypothalamus through ghrelin receptor signaling, leading to pronounced hunger within 20-30 minutes of administration. This effect, while useful in cachectic conditions, limits its utility as a general GH secretagogue.
Legal Status
Not FDA approved. Available as a research chemical. Banned by WADA.
Primary Sources
- Growth hormone releasing peptide-6 stimulates GH secretion via a specific receptor. Endocrinology, 1991.
- Ghrelin mimetics and GH secretagogues: emerging class of drugs. Journal of Endocrinological Investigation, 2001.