GHRP-6
Research OnlyA first-generation growth hormone secretagogue that stimulates GH release through the ghrelin receptor. Less selective than newer alternatives with effects on cortisol and prolactin. Historically significant as the peptide that led to ghrelin discovery. Cuban CIGB leads global cytoprotective research. Not approved for any indication.
Growth Hormone Releasing Peptide-6 · SKF-110679 · Growth Hormone-Releasing Hexapeptide
12 human studies
- Preclinical
- 40%
- Human research
- 27%
Based on 45 cited sources
Numeric assessment unreviewed
A historical numeric score is recorded but has not passed a current, compound-specific assessment review. No numeric score is displayed.
This is a limitation of the numeric assessment, not a measured absence of benefit. It does not re-review the separately recorded catalogue classification or establish efficacy or safety.
GHRP-6 stimulates growth hormone release by activating the ghrelin receptor (GHS-R1a), the same receptor that responds to the endogenous “hunger hormone” ghrelin. Discovered in 1984 before ghrelin itself was identified, GHRP-6 is historically significant as the compound that led to the discovery of the entire ghrelin/GHS system through “reverse pharmacology.”
How It Works (Simplified)
GHRP-6 acts as a potent signal for growth hormone release through multiple interconnected pathways:
Binds to GHS-R1a on pituitary somatotrophs, triggering calcium release and direct GH secretion independent of cAMP pathways.
Acts primarily at the hypothalamus to stimulate GHRH neurons, creating a synergistic amplification of growth hormone release.
Activates NPY/AgRP neurons in the arcuate nucleus, producing strong orexigenic (hunger-inducing) effects via the same pathway as natural ghrelin.
Binds to CD36 scavenger receptor on cardiomyocytes, potentially providing GH-independent cytoprotective effects through Bcl-2 upregulation.
Key Research: Pandya et al. (1998) demonstrated that GHRP-6 requires endogenous GHRH for maximal effect, and patients with hypothalamopituitary disconnection show blocked responses. PMID:9543138
Important Limitations
- Less selective than newer GHRPs (ipamorelin) - also increases cortisol and prolactin
- Strong appetite stimulation may be undesirable for many applications
- No long-term human safety data available
- Cytoprotective effects remain preclinical only despite promising animal data
- Human pharmacokinetics characterized but optimal therapeutic dosing unknown
- Not approved by any regulatory agency; WADA prohibited substance
Reported positives
- Strong appetite stimulation valued for bulking phases
- Improved sleep and recovery reported
- Affordable compared to other GH-related peptides
- Fast onset of GH release
Reported negatives
- Extreme hunger can be overwhelming
- Cortisol elevation greater than GHRP-2
- Water retention and bloating significant
- Lethargy after injection reported
“Known for extreme appetite stimulation. FDA Category 2 restricted. Community often recommends GHRP-2 or ipamorelin instead.”
Self-reported, unverified accounts — not clinical evidence and no substitute for the cited research. Anecdotes are prone to selection bias and placebo effects.
Rapid GH release begins within minutes of administration, with a marked rise in plasma GH after intravenous dosing in healthy men.
PMID:1915110Transient increases in cortisol and ACTH. Appetite stimulation begins. Mild flushing may occur in some subjects.
PMID:9285939GH levels return toward baseline. Elimination half-life approximately 2.5 hours. Distribution half-life only 7.6 minutes indicates rapid tissue uptake.
PMID:23099431No long-term human data available. Unknown whether tachyphylaxis develops. Theoretical concerns about HPA axis effects and chronic appetite stimulation.
Research-based observations
This timeline reflects observations from published clinical and preclinical studies. Individual responses may vary significantly. This is not a guarantee of effects or a dosing schedule. Consult qualified healthcare providers for personalized guidance.
CJC-1295
SynergisticWell-established GHRH+GHRP synergy. GHRP-6 initiates GH pulse via ghrelin receptor while CJC-1295 amplifies release via GHRH receptor. Greater GH release than either alone.
Sermorelin
SynergisticClassic GHRH+GHRP combination. Sermorelin (GHRH analog) and GHRP-6 act through complementary pathways with synergistic effect on GH secretion.
Ipamorelin
CompatibleBoth are GHRPs acting on ghrelin receptor. Ipamorelin is more selective with cleaner profile. No clear rationale for combining same-mechanism agents.
GHRP-2
CompatibleSame receptor target. GHRP-2 is more potent but both affect cortisol/prolactin. No established benefit to combining.
BPC-157
CompatibleCuban CIGB research explores cytoprotective combinations. Different mechanisms; no known contraindications.
Semaglutide
CautionGHRP-6 strongly stimulates appetite via ghrelin signaling, which may counteract semaglutide's appetite-suppressing effects. Also monitor glucose.
Research Note: Interaction data is based on published literature, mechanistic understanding, and theoretical considerations. Most peptide combinations lack direct clinical study. This information is for educational purposes only and does not constitute medical advice. Always consult qualified healthcare providers.
Key Studies Cited
Use the source links in the research discussion above to inspect the referenced records.
This dossier synthesizes available evidence from peer-reviewed literature, regulatory documents, and clinical trial registries. Evidence strength labels summarize the cited material for this entry and should be read alongside its population, model, and study limitations.
For complete methodology details, see our Methodology page.
Important Disclaimer
This dossier is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before making health decisions.
Get Research Alerts
New dossiers and major study summaries delivered to your inbox. Evidence-graded, citation-backed research you can trust.
No spam. Unsubscribe anytime.
Compare GHRP-6
Related Peptides
CJC-1295
DAC:GRF · Modified GRF 1-29 · Tetrasubstituted GRF
A synthetic analog of growth hormone-releasing hormone (GHRH) with extended half-life. Limited clinical development; not approved for any indication.
Follistatin
FST · FS-344 · FS-315 +1
Follistatin is an endogenous protein that binds activin and myostatin. Small human AAV gene-transfer studies and trials of an engineered follistatin-based protein do not establish clinical benefit or safety for native follistatin protein administration.
Human Chorionic Gonadotropin (hCG)
hCG · Choriogonadotropin · Pregnyl +5
A glycoprotein hormone FDA-approved for ovulation induction, cryptorchidism, and hypogonadotropic hypogonadism. Functions as an LH receptor agonist with over 50 years of clinical use in reproductive medicine. Gold standard trigger for assisted reproductive technology.
HMG
Human Menopausal Gonadotropin · Menotropins · hMG +4
A urinary-derived glycoprotein hormone preparation containing both FSH and LH in approximately 1:1 ratio, FDA-approved for female infertility (ovulation induction, ART) and male hypogonadotropic hypogonadism. First used clinically in 1961 by Bruno Lunenfeld, HMG enabled the birth of the first American IVF baby in 1981 and remains a cornerstone of fertility medicine with over 60 years of clinical experience. Highly purified preparations (HP-hMG) demonstrate comparable or slightly superior live birth rates compared to recombinant FSH in IVF.
IGF-1 LR3
Long R3 IGF-1 · LR3-IGF-1 · Insulin-like Growth Factor 1 Long R3
A modified form of IGF-1 with an extended half-life due to reduced binding protein affinity. Used primarily in research for muscle growth and metabolic effects. Not approved for human use; significant safety concerns exist.
Kisspeptin
KISS1 · Metastin · Kisspeptin-54 +3
An endogenous neuropeptide that serves as the master regulator of reproductive function. Acts upstream of GnRH to control puberty, fertility, and the menstrual cycle. Under clinical investigation as a safer IVF trigger and treatment for hypothalamic amenorrhea. Pioneering research led by Imperial College London.
Compared With
6 comparisonsConditions Studied
3 entries- GHRP-6 for GH Deficiency Assessment GHRP-6 has been used as a diagnostic tool to assess pituitary GH reserve. The GH response to GHRP-6 helps distinguish hypothalamic…
- GHRP-6 for Cardiac Protection Cuban CIGB research has extensively studied GHRP-6 for cardioprotection. Animal studies show reduced infarct size, preserved mitoc…
- GHRP-6 for Cachexia/Wasting GHRP-6's strong appetite-stimulating effects via ghrelin receptor activation suggest potential utility in wasting conditions. Howe…