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The Peptide Effect
preclinicalGrowth Hormone

GHRP-6

Also known as: Growth Hormone Releasing Peptide-6, Growth Hormone Releasing Hexapeptide, GHRP-6 Acetate, SKF-110679

GHRP-6 is one of the earliest and most studied synthetic growth hormone secretagogues. It is a hexapeptide that acts as a potent ghrelin receptor agonist, stimulating robust growth hormone release from the pituitary gland. GHRP-6 is notable for its strong appetite-stimulating effects, making it popular among those seeking to increase caloric intake for muscle gain, though this same property limits its appeal for fat loss protocols.

Key Facts

Mechanism
GHRP-6 acts as an agonist at the growth hormone secretagogue receptor (GHS-R1a), the endogenous receptor for ghrelin. Binding triggers a calcium-dependent signaling cascade in pituitary somatotrophs, releasing stored growth hormone in a pulsatile manner. Unlike selective GHRPs such as ipamorelin, GHRP-6 broadly activates ghrelin signaling, which includes stimulation of appetite through hypothalamic neuropeptide Y (NPY) and agouti-related peptide (AgRP) pathways, as well as ACTH-mediated cortisol release and prolactin elevation. GHRP-6 also has demonstrated gastroprotective and neuroprotective properties in preclinical models.
Research Status
preclinical
Half-Life
~15–60 minutes
Molecular Formula
C₄₆H₅₆N₁₂O₆
Primary Use
Growth Hormone
Table of Contents

Benefits

  • Robust, dose-dependent growth hormone release from the pituitarystrong
  • Strong appetite stimulation — beneficial for hard gainers and bulking phasesmoderate
  • Improved gastric motility and gastroprotective effectsmoderate
  • Neuroprotective properties demonstrated in preclinical ischemic brain injury modelspreliminary
  • Enhances recovery through GH/IGF-1 elevation and improved nitrogen retentionmoderate

Dosage Protocols

RouteDosage RangeFrequencyNotes
Subcutaneous injection100–300 mcg2–3× daily on an empty stomachThe saturation dose is approximately 1 mcg/kg body weight. Inject at least 30 minutes before meals.
Subcutaneous injection100 mcg GHRP-6 + 100 mcg CJC-12952–3× dailyGHRH + GHRP stack for synergistic GH release. Expect significant appetite increase.
Subcutaneous injection100–200 mcgOnce at bedtime on an empty stomachSimplified protocol for enhanced nocturnal GH pulse; lower total daily dose reduces cortisol and prolactin impact

Medical disclaimer

Dosage information is provided for educational reference only. Always follow your prescriber's instructions and consult a qualified healthcare provider before starting any peptide protocol.

Side Effects

  • Intense hunger and appetite stimulation (often within 20 minutes of injection)common
  • Elevated cortisol and prolactin levelscommon
  • Water retention and bloatingcommon
  • Numbness or tingling in hands and feetrare
  • Potential increase in blood glucose due to GH-mediated insulin antagonismrare

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Frequently Asked Questions

How bad is the hunger from GHRP-6?
GHRP-6 produces one of the most intense appetite-stimulating effects of any GH secretagogue. Many users report extreme, almost irresistible hunger within 15–30 minutes of injection, lasting 30–60 minutes. This is a direct pharmacological effect of ghrelin receptor activation in the hypothalamus. For those on a caloric surplus or bulking phase, this can be beneficial. For those trying to lose fat or maintain a caloric deficit, GHRP-6 is generally not recommended — ipamorelin or CJC-1295 alone are better choices.
How does GHRP-6 compare to GHRP-2?
GHRP-2 produces a stronger GH release per unit dose compared to GHRP-6, but GHRP-6 causes significantly more hunger. Both elevate cortisol and prolactin, though GHRP-6 tends to have a slightly greater effect on appetite due to its stronger ghrelin pathway activation. GHRP-2 is often preferred when the goal is maximum GH output without as much appetite stimulation, while GHRP-6 is favored when appetite stimulation is desired (e.g., bulking, underweight individuals).
Should GHRP-6 be stacked with a GHRH analog?
Yes. Combining GHRP-6 with a GHRH analog like CJC-1295 or sermorelin produces synergistic GH release — the combined output is significantly greater than either peptide alone. The GHRH analog amplifies the GH pulse that GHRP-6 initiates. This is considered the optimal approach for maximizing GH output. Note that the hunger, cortisol, and prolactin effects of GHRP-6 will still be present in the stack.
When should I inject GHRP-6 relative to meals?
GHRP-6 should always be injected on an empty stomach — ideally after fasting for at least 2 hours, with no food for at least 30 minutes after injection. Elevated blood sugar and insulin significantly blunt the GH response. The intense hunger will make this challenging, which is why many users time their injection 30 minutes before a planned meal. Common timing: upon waking (30 min before breakfast), pre-workout, or at bedtime (at least 2 hours after dinner).
Is GHRP-6 safe for long-term use?
Long-term safety data for GHRP-6 in humans is limited, as most clinical studies have been short-term. Key concerns with extended use include chronic cortisol elevation (which can impair immune function and increase fat storage), sustained prolactin elevation (which can affect hormonal balance), and potential insulin resistance from prolonged GH elevation. Periodic blood work monitoring these markers, along with IGF-1 and fasting glucose, is strongly recommended. This is not medical advice — consult a healthcare provider.

References

  1. 1
    Growth hormone (GH)-releasing peptide-6 stimulates GH release and food intake in the rat(1997)PubMed ↗
  2. 2
    The GH secretagogue GHRP-6: neuroprotective effects in a global cerebral ischemia model(2007)PubMed ↗
  3. 3
    Cytoprotective effects of growth hormone-releasing peptide-6 on gastric mucosal injury(2000)PubMed ↗
  4. 4
    Comparative study of the effects of growth hormone secretagogues: GHRP-6, hexarelin, and ipamorelin on GH release and food intake(2001)PubMed ↗

Last updated: 2026-02-14