GHRP-6
Also known as: Growth Hormone Releasing Peptide-6
One of the oldest growth hormone peptides, developed in the 1980s. Known for strong GH release but also extreme hunger — it makes you ravenous within 20-30 minutes of injection. This makes it bad for fat loss but potentially useful for people who need to gain weight or struggle with appetite. Research on this peptide actually led to the discovery of ghrelin (the hunger hormone) itself. Also shows protective effects on the heart, liver, and stomach lining.
Dosage
100-300 mcg subcutaneous 2-3x daily
Dosages shown are for research reference only. Always consult a qualified healthcare provider.
Administration
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Effects
GH Release
Strong growth hormone release — one of the earliest and best-studied GHRPs.
Appetite Increase
Strongest appetite stimulation among all GHRPs — intense hunger within 20-30 minutes.
Cytoprotection
Protective effects on cardiac, hepatic, and gastric tissue in animal models.
Mechanism of Action
GHRP-6 (Growth Hormone Releasing Peptide-6) is one of the earliest synthetic GH secretagogues developed, first characterized in the 1980s. It is a hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) that acts as a full agonist at the GHS-R1a receptor, the subsequently identified endogenous receptor for ghrelin. GHRP-6 actually preceded the discovery of ghrelin itself — research on GHRPs led scientists to identify the receptor, which in turn led to the discovery of ghrelin as the endogenous ligand.
The GH-releasing mechanism follows the standard GHS-R1a pathway: Gq/11-mediated PLC activation, IP3-dependent calcium mobilization, and GH vesicle exocytosis from pituitary somatotrophs. GHRP-6 also suppresses somatostatin and stimulates hypothalamic GHRH release. What distinguishes GHRP-6 from later GHRPs is its pronounced ghrelin-mimetic effect on appetite regulation — it strongly activates orexigenic NPY/AgRP neurons in the hypothalamic arcuate nucleus, producing intense hunger within 20-30 minutes of injection.
This strong appetite stimulation, while problematic for those seeking fat loss, makes GHRP-6 potentially useful in clinical settings involving cachexia, anorexia, or conditions requiring caloric intake increase. GHRP-6 also demonstrates cytoprotective properties in various tissues. Research has shown protective effects in cardiac tissue (reducing ischemia-reperfusion injury), hepatic tissue (attenuating fibrosis in animal models), and gastric mucosa. These cytoprotective effects appear to be mediated through pathways independent of GH release, involving anti-inflammatory and anti-apoptotic signaling. The compound also elevates cortisol and prolactin to a moderate degree, though less than hexarelin.
Regulatory Status
Not FDA approved. Research peptide. One of the oldest and most studied GHRPs. Available through research suppliers.
Risks & Safety
Common
intense hunger, water retention and bloating, moderate cortisol and prolactin elevation, headache.
Serious
disrupted blood sugar control, tolerance build-up with continuous use, breast tissue growth in men from prolactin.
Rare
significant swelling, allergic reactions.
Compare GHRP-6 With
Research Papers
30Published: February 28, 2026
AI Summary
GHRP-6 reduced acute lung injury from LPS or zymosan in mice, lessening inflammation, improving lung function, and limiting later fibrosis. The findings suggest GHRP-6 may protect the lungs in acute respiratory syndromes.
Published: January 8, 2026
AI Summary
Oral salmon ghrelin increased feeding in carp via local ghrelin receptors and sensory nerves, not systemic absorption. Blocking with [D-Lys3]-GHRP-6 or capsaicin abolished the effect, showing a non-circulatory gut-brain pathway in fish.
Published: December 5, 2025
AI Summary
LEAP-2 reduced food intake in chickens via ghrelin and cannabinoid receptors. Co-injection with [D-Lys-3]-GHRP-6 partly reversed LEAP2-induced hypophagia, while cannabinoid blockers amplified it.
Published: November 30, 2025
AI Summary
A GHRP-6 hydrogel reprogrammed kidney cell metabolism and improved recovery from acute kidney injury in mice by activating mTOR-P70 and enriching metabolites involved in amino acid and fatty acid pathways.
Published: November 12, 2025
AI Summary
GHRP-6 analogs with aza-isotryptophan showed CD36 binding and modulated inflammatory responses. The work explores novel peptide chemistry for receptor targeting and inflammation control.
Published: July 24, 2025
AI Summary
Dietary GHRP-6 stabilized metabolism and boosted immune gene expression in sea bream after immune challenge. The peptide appears safe and may improve immune resilience and production efficiency in aquaculture.
Published: June 1, 2025
AI Summary
A butyrylcholinesterase inhibitor improved depression, cognition, and anhedonia in a rat model, possibly via ghrelin and dopamine. The work explores how these systems interact in treatment-resistant depression.
Published: April 8, 2025
AI Summary
The herbal formula DCH improved brain injury and cognition in rats, partly by modulating the ghrelin/GHSR pathway. The work supports DCH as a potential neuroprotective treatment for traumatic brain injury.
Published: March 10, 2025
AI Summary
Blocking GHSR with [D-Lys3]-GHRP-6 or knocking out the receptor reduced liver damage from E. granulosus infection in mice. Lower ghrelin signaling improved inflammation and parasite control.
Published: May 27, 2025
AI Summary
GHRP-6 (CIGB-500) was well-tolerated in dogs at doses up to 2000 µg/kg/day for 28 days. Transient effects like reduced heart rate were reversible, supporting its safety profile for heart attack treatment.
Published: February 28, 2025
AI Summary
Ghrelin reduced water intake in eels through a mechanism not blocked by [D-Lys3] GHRP-6 or mimicked by GHRP-6, suggesting a different ghrelin receptor subtype. The effect was as strong as ANP but independent of blood pressure.
Published: January 8, 2025
AI Summary
Ghrelin and GHRP-6 reduced both hyperactivity at 12 h and hypoactivity at 24 h during nicotine withdrawal in rats. Both peptides may help normalize activity changes during withdrawal.
Published: February 4, 2025
AI Summary
Intranasal GHRP-6 increased food intake and activated appetite-regulating neurons in mice, while raising growth hormone. It engaged the brain ghrelin system effectively, unlike ghrelin or MK-0677 given the same way.
Published: October 9, 2024
AI Summary
Ghrelin was needed for blood pressure to drop during torpor in fasting animals. The work tests whether ghrelin actively regulates cardiovascular function during this hypothermic state.
Published: October 21, 2024
AI Summary
Abstract too short to summarize.
Published: October 16, 2024
AI Summary
Ghrelin inhibited calcium channels in stomach vagal neurons via GHSR1a through voltage-dependent and voltage-independent pathways. [D-Lys3]-GHRP-6 blocked the effect, clarifying how ghrelin regulates gastric vagal signaling.
Published: November 19, 2024
AI Summary
Rikkunshito improved anorexia through ghrelin and orexin, activating the hypothalamus and reward pathways. The work clarifies how this traditional medicine affects appetite and food motivation.
Published: January 12, 2025
AI Summary
Chimeric peptides combining endomorphins with [D-Lys3]-GHRP-6 produced pain relief with less tolerance than endomorphins alone. The approach may help develop safer opioid-like analgesics.
Published: July 25, 2024
AI Summary
Ghrelin protected pancreatic beta cells from glucolipotoxicity by reducing endoplasmic reticulum stress and the IRE1/JNK pathway. The work suggests ghrelin may help preserve beta-cell function in diabetes.
Published: October 6, 2024
AI Summary
Calorie restriction expanded stomach ghrelin cells via Notch and FOXO1. Blocking the ghrelin receptor with GHRP-6 reversed the effect, and tirzepatide also increased ghrelin cells in mice.
Published: May 29, 2024
AI Summary
GHRP-6 prevented doxorubicin-induced heart failure and multi-organ damage in rats by boosting antioxidants, Bcl-2, and mitochondrial integrity. The findings support GHRP-6 as a potential cardioprotective agent during chemotherapy.
Published: June 14, 2024
AI Summary
Ghrelin reduced intestinal ischemia-reperfusion injury by activating GHSR-1α and Sirt1/FOXO1. [D-Lys3]-GHRP-6 blocked the effect, showing that ghrelin protects the gut through this pathway.
Published: May 20, 2024
AI Summary
Ghrelin influenced endoplasmic reticulum stress signaling in gestational diabetes. The work explores how ghrelin-regulated ERS pathways may contribute to GDM.
Published: November 30, 2023
AI Summary
Ghrelin imbalance during implantation impaired embryo development by disrupting uterine immune balance and nitric oxide. The work links ghrelin to implantation success and pregnancy outcomes.
Published: November 29, 2023
AI Summary
Blocking the ghrelin receptor with D-Lys-3-GHRP-6 worsened seizures in kindled rats, while an inverse agonist reduced them. The type of ghrelin receptor ligand matters for seizure control.
Published: December 8, 2023
AI Summary
GHRP-4, GHRP-6, and Sermorelin (22-29) were stable in blood and against enzymes, making them suitable as internal standards for peptide quantification in biological samples.
Published: October 31, 2023
AI Summary
Desacylghrelin affected GHS-R1 expression and cell differentiation in placental BeWo cells. The work explores how unacylated ghrelin influences placental function and fetal growth.
Published: August 7, 2023
AI Summary
Blocking ghrelin with [D-Lys3]-GHRP-6 in pigs increased fat breakdown, liver fatty acid oxidation, and gluconeogenesis. Ghrelin inhibition shifted energy metabolism without affecting liver fat uptake or synthesis.
Published: February 6, 2023
AI Summary
Ghrelin promoted blood vessel growth in human coronary endothelial cells under low oxygen via VEGF, Ang-1, Ang-2, and Tie2. [D-Lys3]-GHRP-6 blocked the effect, suggesting ghrelin may support heart repair after ischemia.
Published: February 20, 2023
AI Summary
Ghrelin reduced LPS/leptin-induced MUC5AC mucus production in nasal epithelial cells. The work explores ghrelin as a potential treatment for obesity-related inflammatory airway disease.
Frequently Asked Questions
What is GHRP-6?
One of the oldest growth hormone peptides, developed in the 1980s. Known for strong GH release but also extreme hunger — it makes you ravenous within 20-30 minutes of injection. This makes it bad for fat loss but potentially useful for people who need to gain weight or struggle with appetite. Research on this peptide actually led to the discovery of ghrelin (the hunger hormone) itself. Also shows protective effects on the heart, liver, and stomach lining.
What is GHRP-6 used for?
One of the oldest growth hormone peptides, developed in the 1980s. Known for strong GH release but also extreme hunger — it makes you ravenous within 20-30 minutes of injection. This makes it bad for fat loss but potentially useful for people who need to gain weight or struggle with appetite. Research on this peptide actually led to the discovery of ghrelin (the hunger hormone) itself. Also shows protective effects on the heart, liver, and stomach lining.
What is the dosage for GHRP-6?
Standard: 100-300 mcg subcutaneous two or three times daily on an empty stomach. Often combined with GHRH analogues (CJC-1295 or Sermorelin) for synergistic GH release. Must be administered fasted for optimal GH response.
What are the side effects of GHRP-6?
Common: intense hunger, water retention and bloating, moderate cortisol and prolactin elevation, headache. Serious: disrupted blood sugar control, tolerance build-up with continuous use, breast tissue growth in men from prolactin. Rare: significant swelling, allergic reactions.
How does GHRP-6 work?
GHRP-6 (Growth Hormone Releasing Peptide-6) is one of the earliest synthetic GH secretagogues developed, first characterized in the 1980s. It is a hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) that acts as a full agonist at the GHS-R1a receptor, the subsequently identified endogenous receptor for ghrelin. GHRP-6 actually preceded the discovery of ghrelin itself — research on GHRPs led scientists to identify the receptor, which in turn led to the discovery of ghrelin as the endogenous ligand. The GH-releasing mechanism follows the standard GHS-R1a pathway: Gq/11-mediated PLC activation, IP3-dependent calcium mobilization, and GH vesicle exocytosis from pituitary somatotrophs. GHRP-6 also suppresses somatostatin and stimulates hypothalamic GHRH release. What distinguishes GHRP-6 from later GHRPs is its pronounced ghrelin-mimetic effect on appetite regulation — it strongly activates orexigenic NPY/AgRP neurons in the hypothalamic arcuate nucleus, producing intense hunger within 20-30 minutes of injection. This strong appetite stimulation, while problematic for those seeking fat loss, makes GHRP-6 potentially useful in clinical settings involving cachexia, anorexia, or conditions requiring caloric intake increase. GHRP-6 also demonstrates cytoprotective properties in various tissues. Research has shown protective effects in cardiac tissue (reducing ischemia-reperfusion injury), hepatic tissue (attenuating fibrosis in animal models), and gastric mucosa. These cytoprotective effects appear to be mediated through pathways independent of GH release, involving anti-inflammatory and anti-apoptotic signaling. The compound also elevates cortisol and prolactin to a moderate degree, though less than hexarelin.
How is GHRP-6 administered?
GHRP-6 is administered via subcutaneous injection.
What is the half-life of GHRP-6?
The half-life of GHRP-6 is 2-3 hours.
Is GHRP-6 legal?
Not FDA approved. Research peptide. One of the oldest and most studied GHRPs. Available through research suppliers.
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