Extensively Studied

GHRP-6

Growth Hormone Secretagogue | GH Release & Cardioprotection

GHRP-6 (Growth Hormone Releasing Peptide-6) is a synthetic hexapeptide that stimulates growth hormone release through activation of the ghrelin receptor (GHS-R1a) and CD36 receptor. Developed in the 1980s as one of the first growth hormone secretagogues, it acts through a PKC/calcium-dependent pathway distinct from GHRH. Beyond GH release, GHRP-6 has demonstrated significant cardioprotective, wound healing, and cytoprotective properties in preclinical and early clinical research. It is notable for its strong appetite-stimulating effects via direct ghrelin receptor activation and its synergistic interaction with GHRH-class peptides.

Daily dose

100-300mcg

Frequency

2-3x daily

Cycle length

8-12 weeks

Storage

2-8°C

Key benefits

Growth hormone release, cardioprotection, wound healing acceleration, appetite stimulation, cytoprotective effects across multiple organ systems

How it works

Activates GHS-R1a (ghrelin receptor) for GH release through a PKC/calcium-dependent, cAMP-independent pathway via diacylglycerol/inositol trisphosphate signaling at both pituitary and hypothalamic sites. Separately acts as a CD36 receptor antagonist, blocking fatty acid uptake and providing cytoprotective and cardioprotective effects by preventing lipotoxicity. Requires endogenous GHRH for maximal GH stimulation—GHRH antagonist reduces GHRP-6-induced GH response by ~80% (Pandya et al., 1998). Exhibits tachyphylaxis with continuous exposure, necessitating pulsed dosing strategies.

Dosage protocols

Goal

GH Release (Standard)

Dose

100mcg · 3x daily on empty stomach

Route

SubQ

Goal

GH Release (Moderate)

Dose

200mcg · 2-3x daily on empty stomach

Route

SubQ

Goal

Combined with GHRH Peptide

Dose

100mcg + 100mcg CJC-1295 · 2-3x daily

Route

SubQ

Research indications

hormonal

Growth Hormone Release — Potent GH secretagogue with dose-dependent release demonstrated in human clinical studies via GHS-R1a activation

Synergy with GHRH Peptides — Simultaneous stimulation with GHRH-class peptides produces synergistic GH response 2-3x greater than either alone

IGF-1 Elevation — Sustained GH release increases downstream IGF-1 for anabolic and tissue repair support

cardiovascular

Cardioprotection — In preclinical models, rescued >70% of ischemic myocardium in pigs. 100% survival in canine acute MI model vs 50% in controls. Human efficacy under investigation.

Doxorubicin Cardiotoxicity Prevention — Completely prevented cardiac dysfunction in doxorubicin-treated rats through prosurvival pathway activation (2024 preclinical study)

Anti-Fibrotic Cardiac Effects — Reduces cardiac fibrosis by increasing MMP-2/MMP-9 activities and decreasing TIMP-1 expression

tissue Repair

Wound Healing — Topical GHRP-6 significantly accelerated wound closure and prevented hypertrophic scar formation in 90.5% of treated wounds

Neuroprotection — Combined with EGF, improved neurological outcomes and survival in Phase I/II acute ischemic stroke trial (2024)

Multi-Organ Cytoprotection — Pharmacological preconditioning reduces kidney, lung, and intestinal damage during ischemia/reperfusion injury

muscle Growth

Lean Mass Support — GH and IGF-1 elevation supports muscle protein synthesis and body composition improvements over 8-12 week protocols

Recovery Enhancement — Pulsatile GH release supports exercise recovery, sleep quality, and tissue repair processes

Appetite Stimulation — Strong ghrelin-mediated appetite increase supports caloric surplus for muscle growth phases

Administration

injectable

oral

topical

Interactions

Synergistic

CJC-1295 — Strong synergy - GHRP-6 amplifies the GH pulse initiated by CJC-1295 through complementary receptor pathways (GHS-R1a + GHRH-R). Combined GH response is 2-3x greater than either alone. Well-established clinical combination.

Use Caution

CJC-1295 with DAC — DAC version provides sustained GHRH stimulation (6-8 day half-life) which may lead to continuous GH elevation ("GH bleed") rather than pulsatile release when combined with GHRP-6. Pulsatile GH is preferred for mimicking natural physiology and avoiding receptor desensitization. Non-DAC CJC-1295 (Mod GRF 1-29) preferred for combination protocols.

Use Caution

Ipamorelin — Both target GHS-R1a for GH release. Combination is redundant for GH stimulation—no additional GH benefit. Choose based on profile: GHRP-6 offers appetite stimulation and broader cytoprotective effects (via CD36 antagonism), while ipamorelin provides more selective GH release with minimal cortisol/prolactin elevation. Not unsafe, but therapeutically redundant.

Use Caution

Hexarelin — Both are GHRP-class secretagogues acting on GHS-R1a. Hexarelin is a GHRP-6 derivative with 2-methyl-Trp substitution providing higher potency. Combination is redundant for GH stimulation and may amplify cortisol/prolactin side effects without proportional GH benefit. Choose one based on desired potency profile.

Avoid Combination

MK-677 — MK-677 (ibutamoren) is an oral GHS-R1a agonist with a ~24-hour half-life, providing continuous ghrelin receptor stimulation. Combining with GHRP-6 creates redundant receptor activation with significantly amplified side effects (appetite, cortisol, prolactin elevation) without proportional GH benefit. Avoid combination due to side effect burden from sustained + pulsed receptor stimulation.

Compatible

BPC-157 — Different mechanisms with no known interactions. BPC-157 focuses on tissue repair through distinct pathways. May complement recovery protocols.

Compatible

TB-500 — Different mechanisms - TB-500 works through actin regulation and angiogenesis while GHRP-6 acts through GH release and ghrelin signaling. No known negative interactions.

Monitor Combination

HGH — Exogenous HGH combined with GHRP-6 may produce excessive GH/IGF-1 levels. If combining, use lower doses of each and monitor IGF-1 levels. GHRP-6 stimulates endogenous GH which is preferable to exogenous for pulsatile release.

Synergistic

Sermorelin — GHRH analog + GHRP creates the classic synergistic combination. Sermorelin stimulates via GHRH receptor while GHRP-6 acts through GHS-R1a for amplified pulsatile GH release.

Use Caution

Insulin — GHRP-6 may increase blood glucose and reduce insulin sensitivity. Diabetic patients or those using insulin should monitor glucose closely and adjust doses under medical supervision.

Safety notes

Proven safe in human Phase I dose-escalation trial with IV administration

Strong appetite increase is expected (ghrelin receptor activation) - not an adverse effect

Transiently elevates cortisol and prolactin, particularly at doses above 100mcg

May increase blood glucose and reduce insulin sensitivity with prolonged use - monitor if diabetic or insulin resistant

Avoid use in active cancer - GH/IGF-1 elevation may promote tumor growth

Must inject on empty stomach - food significantly blunts GH response

Less selective than ipamorelin (elevates cortisol, prolactin, and appetite)

No pharmacological interaction with beta-blocker metoprolol demonstrated in clinical studies

Prolonged continuous use may lead to ghrelin receptor (GHS-R1a) desensitization, reducing GH response. Cycling (8-12 weeks on, 4-8 weeks off) recommended to maintain efficacy.

Research studies

Cytoprotective Effects Review (2017)

Systematic review | PubMed/MEDLINE | 1980-2017 | Multi-organ cytoprotection

Comprehensive review establishing GHRPs as cytoprotective agents beyond GH secretion. GHRP-6 demonstrated pharmacological preconditioning across cardiac, renal, pulmonary, and intestinal tissues during ischemia/reperfusion injury via PI-3K/AKT1 pathway activation.

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Prevention of Doxorubicin Cardiotoxicity (2024)

Rats | 400μg/kg IP twice daily | 52 days | Complete cardiac function preservation

Concurrent GHRP-6 administration completely prevented dilated cardiomyopathy in doxorubicin-treated rats, preserving left ventricular systolic function through Bcl-2 upregulation, mitochondrial preservation, and multi-organ protection.

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Phase I/II Acute Ischemic Stroke Trial (2024)

Human | 36 patients | EGF + GHRP-6 (3.5mg or 5mg IV) | 7 days treatment | 180-day follow-up

Randomized clinical trial of EGF + GHRP-6 combination in acute ischemic stroke. Treated groups showed favorable neurological and functional evolution at 90 and 180 days with higher survival rate and fewer serious adverse events (20-30% vs 56.2% in controls).

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GHRP-6 Requires Endogenous GHRH for Maximal GH Stimulation (1998)

Human | 9 healthy males | GHRP-6 with/without GHRH antagonist | Single dose

Landmark study demonstrating that GHRH antagonist eliminated most of the GH response to GHRP-6 (maximal GH dropped from 33.8 to 6.2 μg/L), establishing that endogenous GHRH is required for optimal GHRP-6 effectiveness.

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Wound Healing and Hypertrophic Scar Prevention (2016)

Rats + Rabbits | Topical 400μg/ml | 4-30 days | Accelerated closure and 90.5% scar prevention

Topical GHRP-6 significantly enhanced wound closure within 24 hours in rat model. In rabbit hypertrophic scar model, aborted scar formation in 90.5% of treated wounds through TGF-β1/CTGF downregulation and PPARG upregulation.

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Pharmacokinetic Study in Healthy Volunteers

Human | 9 healthy males | IV administration | Phase I dose-escalation

First human pharmacokinetic characterization of GHRP-6. Bi-exponential disposition with distribution half-life of 7.6±1.9 minutes and elimination half-life of 2.5±1.1 hours. Proven safe across dose-escalation protocol.

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Related compounds

Hexarelin (Examorelin)Ipamorelin MK-677 CJC-1295 (no DAC) / Ipamorelin Protocol