GHRP-6
PeptideThe medical score (28) is substantially lower than the community score (58), as clinical efficacy evidence for bodybuilding indications in humans is lacking [s6, s8], while the community frequently reports subjective anabolic and regenerative effects [c1, c2]. The divergence reflects the typical gap between preclinical evidence and self-reporting in research peptides.
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TL;DR
GHRP-6 is a synthetic hexapeptide that stimulates growth hormone release via GHS-R1a receptor activation, engaging both pituitary and hypothalamic signaling pathways. The compound is experimental, not clinically approved, and carries an unfavorable benefit-risk profile (benefit 2/5, risk 3/5). Medical evidence is weak (28/100), while community reports suggest moderate effects. No therapeutic application in humans is scientifically established.
Description
Synthetic hexapeptide that triggers growth hormone pulses via activation of the ghrelin receptor (GHS-R1a); experimental, not approved [s1, s2].
GHRP-6 (Growth Hormone Releasing Peptide-6) is a synthetic hexapeptide with the amino acid sequence His-D-Trp-Ala-Trp-D-Phe-Lys-NH2. It was discovered in the 1980s by Cyril Bowers during work on enkephalin analogues and was the first synthetic peptide designed to specifically stimulate growth hormone secretion [s1, s2]. GHRP-6 binds to the GHS-R1a receptor (ghrelin receptor) in the pituitary gland and hypothalamus, thereby triggering a pulsatile rise in growth hormone (GH) [s1, s3]. Compared to GHRH, GHRP-6 acts via an independent receptor pathway, enabling synergistic combination with GHRH analogues (e.g., CJC-1295, Sermorelin) [s7]. Beyond GH release, GHRP-6 also activates the hypothalamic-pituitary-adrenocortical axis (HPA axis), which can lead to a transient increase in cortisol and prolactin [s4, s5]. A pronounced appetite stimulus through ghrelin release is the most commonly reported effect [s4, s5]. Preclinical studies (animal and cell models) demonstrate cardioprotective, anti-inflammatory, and tissue-preserving properties via the PI3K/Akt signaling pathway [s6]. A Phase I/II human study tested GHRP-6 in combination with EGF in acute ischemic stroke [s8]. Overall, clinical data in humans are very limited. GHRP-6 is not approved for human use. The substance is classified as a research chemical in Germany and is prohibited by WADA [s9, s10, s11].
Legal Status (DE)
GHRP-6 is not approved as a medicinal product in Germany and has no marketable status as a dietary supplement. It falls under the Medicinal Products Act (AMG) if marketed with a therapeutic intended purpose. Personal possession for self-use is legally ambiguous; commercial distribution to end consumers is not legally permitted. GHRP-6 is frequently declared as a "research chemical," which does not, however, constitute a legal exemption [s10, s11]. Furthermore, GHRP-6 is explicitly listed by WADA as a prohibited substance (category S2) — both in- and out-of-competition [s9].
Mechanism of Action
GHRP-6 exerts its effects primarily through two mechanisms [s1, s3]: 1. Direct GHS-R1a activation: GHRP-6 binds to the GHS-R1a receptor (ghrelin receptor) on somatotropic cells of the pituitary gland. This activates the Gq protein–PLC–calcium signaling pathway, resulting in growth hormone release [s3]. Simultaneously, GHS-R1a receptors in the hypothalamus are activated, which can further increase GHRH release [s1]. 2. Inhibition of somatostatin tone: GHRP-6 indirectly reduces the inhibitory effect of somatostatin on GH release, thereby amplifying the GH pulse [s2]. Side effects on other axes: - HPA axis: Activation leads to a transient cortisol increase [s4, s5]. - Prolactin axis: Elevated prolactin secretion at doses above 100 mcg [s5]. - Appetite: Ghrelin release stimulates the hunger center in the hypothalamus, resulting in strong appetite shortly after injection [s4]. Cytoprotective effects (preclinical): In animal and cell studies, GHRP-6 activates the PI3K/Akt signaling pathway in cardiac, hepatic, and neural tissue, mediating anti-apoptotic and anti-inflammatory effects [s6]. Reductions in TGF-β1, TNF-α, and oxidative stress, as well as promotion of mitochondrial biogenesis, have been observed in animal models [s6, s8]. The released GH secondarily stimulates IGF-1 production in the liver, which accounts for anabolic effects on muscle and bone tissue [s2].
Dosing
GH-Stimulation (allgemein)
- Dose
- 100 mcg per injection
- Frequency
- 2–3× täglich, subkutan
- Route
- injektion-subkutan
- Duration
- 8–12 Wochen, dann Pause
- Timing
- Inject fasted (at least 2h after last meal, at least 30 min before next meal), as glucose and fatty acids attenuate the GH response
- With food
- vermeiden
Kombination mit GHRH-Analogon (z. B. CJC-1295 no-DAC)
- Dose
- 100 mcg GHRP-6 + 100 mcg CJC-1295 (no-DAC) per injection
- Frequency
- 2–3× täglich, subkutan
- Route
- injektion-subkutan
- Duration
- 8–12 Wochen
- Timing
- Inject simultaneously fasted for synergistic GH pulse
- With food
- vermeiden
No officially validated maximum human dose exists, as GHRP-6 is not approved. Single doses above 300 mcg are not recommended in research protocols; at ≥100 mcg, the risk of cortisol and prolactin elevations increases [s5]. Any use outside controlled studies must be considered experimental [s10].
An insulin syringe (0.3–1 ml) is the standard administration device for subcutaneous injection. Bacteriostatic water or sterile water is used for reconstitution. No officially recommended human dose exists [s10].
Calculate reconstitution, plan dosing, look up injection technique
Side Effects
| Side Effect | Frequency | Severity |
|---|---|---|
| Starker Appetitreiz (Heißhunger) kurz nach der Injektion Ghrelin release activates hypothalamic hunger signaling pathways; this effect is the most frequent and characteristic distinction from more selective GHRPs such as ipamorelin [s4, s5]. | häufig | leicht |
| Transienter Cortisol-Anstieg HPA axis activation; at doses ≤100 mcg generally not clinically relevant according to study data, but detectable at higher doses [s5]. | gelegentlich | leicht |
| Transienter Prolaktin-Anstieg At doses >100 mcg; can lead to galactorrhea or loss of libido with prolonged use [s5]. | gelegentlich | leicht |
| Wassereinlagerungen (Ödeme) GH-induced sodium retention; typical for GH secretagogues, usually reversible upon discontinuation [s4]. | gelegentlich | leicht |
| Injektionsstellen-Reaktionen (Rötung, Schwellung, Schmerz) Local tissue irritation from subcutaneous injection; common with all peptide injections [s4]. | häufig | leicht |
| Kribbeln oder Taubheitsgefühl in Händen/Handgelenken GH-induced carpal tunnel syndrome-like symptom; described in community reports [c1]. | gelegentlich | leicht |
| Hitzewallungen, Schwindel nach Injektion Transient vasodilatory response following GHRP-6 injection; documented in user reports and case reports [c1]. | gelegentlich | leicht |
| Gynäkomastie (bei längerem Prolaktin-Anstieg) Theoretical with prolonged hyperprolactinemia; occasionally mentioned in community reports, no systematic data [s5, c1]. | selten | moderat |
| Verschlechterung der Insulinsensitivität GH can increase insulin resistance with prolonged use; relevant at supraphysiological GH levels [s2]. | theoretisch | moderat |
Contraindications
GH and IGF-1 can promote tumor growth; all GH secretagogues are contraindicated in active malignancy [s2].
GH elevation impairs insulin sensitivity and can significantly destabilize blood glucose [s2].
No human safety data available; prolactin elevation and unresolved effects on the fetus render use unacceptable [s10].
GHRP-6 can elevate prolactin and exacerbate pre-existing hyperprolactinemia [s5].
Impaired renal clearance of peptides; risk of accumulation and uncontrolled GH/IGF-1 levels possible [s13].
Further GH stimulation is counterproductive and potentially dangerous [s2].
Uncontrolled GH stimulation may affect epiphyseal plates and normal growth; no safety data available [s10].
Interactions
Synergistic
Combined use with GHRH analogues synergistically amplifies the GH pulse through dual receptor activation (GHS-R1a + GHRH-R) [s7].
Both activate GHS-R1a; GHRP-2 has slightly fewer appetite and cortisol side effects; structural similarity and additive GH stimulation possible when stacking [s14].
CJC-1295 DAC prolongs the GH pulse through extended GHRH receptor activation, while GHRP-6 triggers a rapid GH burst – the combination increases GH secretion more than either substance alone.
Sermorelin, as a GHRH analogue, complements GHRP-6 by activating the GHRH receptor, producing a more physiological and stronger GH pulse than either agent alone.
Ipamorelin and GHRP-6 both activate GHS-R1a, with ipamorelin being more selective and having fewer cortisol/prolactin side effects. Combination can provide an additive GH effect at low doses.
Hexarelin is the most potent GHRP and can be combined short-term with GHRP-6, though the risk of desensitization is increased with long-term stacking.
GHRP-6 combined with BPC-157 is used to support healing of tendons, joints, and muscles, as both peptides activate complementary regenerative mechanisms.
The combination of GHRP-6 and TB-500 is used to maximize recovery following injury or surgery, with both substances targeting distinct healing pathways.
Caution
GH elevation by GHRP-6 can increase insulin resistance and alter insulin requirements/dosing in diabetic patients; blood glucose monitoring required [s2].
Additive cortisol elevation possible; combined HPA axis activation of both substances may be clinically relevant [s5].
GH-induced insulin resistance may reduce the efficacy of antidiabetic agents and require dose adjustments [s2].
GHRP-6 increases prolactin; this may counteract the effect of cabergoline/bromocriptine [s5].
Simultaneous stacking of two or more GHRPs (e.g., ipamorelin + GHRP-6 + hexarelin) results in diminishing additional benefit alongside increased side effects such as elevated cortisol and prolactin levels and enhanced appetite.
Hexarelin has the highest desensitization rate among GHRPs; long-term combination with GHRP-6 may lead to rapid loss of efficacy of both substances.
Studies
Tier A — High Evidence
Outcome: Safety and tolerability of EGF+GHRP-6 combination in acute ischemic stroke; 30% serious adverse events as safety threshold
Effect Size: No safety signal above threshold; tolerability confirmed; functional outcomes exploratively positive
Tier B — Moderate Evidence
Outcome: Pharmacokinetic parameters (half-life, Cmax, AUC) following subcutaneous GHRP-6 injection
Effect Size: Short half-life (~15–30 min); rapid GH increase within 15–30 min post-injection
Outcome: GH response to GHRP-6 vs. GHRH in hypothyroid patients; GHRP-6 elicited significantly higher GH release than GHRH
Effect Size: Hypothyroid patients: GH 12.6 ± 1.9 µg/L after GHRP-6 vs. 4.1 ± 0.9 µg/L after GHRH (p < 0.05)
Tier C — Low Evidence
Outcome: Ventricular remodeling and systolic dysfunction following myocardial infarction; GHRP-6 reduced inflammatory cell infiltration and scar tissue
Effect Size: Significant improvement in cardiac endpoints vs. control; details in PMC full text
Community Evidence
Top reported benefits
- Increase in muscle mass when combined with CJC-1295
- Accelerated recovery after intense training
- Improved sleep (deep sleep phases)
- Mild fat reduction with consistent use
Top reported issues
- Extreme food cravings shortly after injection (very frequently reported)
- Cortisol and prolactin elevation as undesired side effects
- Preference for Ipamorelin or GHRP-2 due to better side effect profile
- Difficulties sourcing high-quality product
GHRP-6 is increasingly referred to in the community as a "dirty" GHRP, as it stimulates cortisol and prolactin in addition to GH [c1, c3]. Experienced users frequently advise more selective alternatives (Ipamorelin) or recommend GHRP-6 only in combination with CJC-1295 [c2]. The WADA prohibited status is largely known among athletes in the community [c1].
Scientific Sources
- GHRP-6 (Growth Hormone Releasing Peptide-6): Research Evidence & Safety Profile
PeptideInsight Editorial Team (2024). PeptideInsight (Online Resource)CLink - GHRP-6 – Wirkung, Anwendung und Risiken
Artgerecht.com Editorial Team (2024). Artgerecht.com Glossar (Online Resource)CLink - Peptide legal in Deutschland? Rechtslage 2026
Peptide Culture Editorial Team (2026). Peptide-Culture.com (Online Resource)CLink - GHRP-6 Protocol: Dosing, Timing & Cycle Guide (Peptide Dosages)
PeptideDosages.com Editorial Team (2024). PeptideDosages.com (Online Resource)CLink - Pharmacokinetic study of Growth Hormone-Releasing Peptide 6 (GHRP-6) in nine male healthy volunteers
Berlanga Acosta J, et al. (2004). ResearchGate / Peer-reviewed journal (original)BLink - GHRP-2 vs. GHRP-6: Die Feinheiten von Wachstumshormon-freisetzenden Peptiden im Detail
Anabolic Planner Editorial Team (2024). AnabolicPlanner.com (Online Resource)CLink - Growth hormone responses to GH-releasing peptide (GHRP-6) in hypothyroidism
Valcavi R, Zini M, Portioli I, et al. (1997). Clinical EndocrinologyBPMID:9156038 - Growth hormone releasing peptide-6 (GHRP-6) prevents doxorubicin-induced myocardial and extra-myocardial damages by activating prosurvival mechanisms
Berlanga-Acosta J, Cibrian D, Valiente-Mustelier J, Suárez-Alba J, García-Ojalvo A, Falcón-Cama V, Jiang B, Wang L, Guillén-Nieto G (2024). Frontiers in PharmacologyCPMID:38873418DOI - On the in vitro and in vivo activity of a new synthetic hexapeptide that acts on the pituitary to specifically release growth hormone
Bowers CY, Momany FA, Reynolds GA, Hong A (1984). EndocrinologyCLink - GHRP-6: Growth Hormone Releasing Peptide-6 Guide
Peptidepedia Editorial Team (2024). Peptidepedia (Online Resource)CLink - GHRP-6: Complete Science Guide
PeptideBond Editorial Team (2024). PeptideBond.com (Online Resource)CLink - GHRP-6 side effects and safety considerations
Peptides Lab UK Editorial Team (2024). PeptidesLabUK (Online Resource)CLink - GHRP-6 Nebenwirkungen
Steroidzentrum.de Editorial Team (2023). Steroidzentrum.de (Online Resource)CLink - Growth Hormone-Releasing Peptide-6 (GHRP-6) Ameliorates Post-Infarct Ventricular Remodeling and Systolic Dysfunction in a Model of Permanent Coronary Ligation
Unpublished Authors et al. (2025). PMC / PubMed CentralCLink - GHRP-6 Protocol: Dosing, Timing & Cycle Guide
ThePeptideGuides Editorial Team (2024). ThePeptideGuides.com (Online Resource)CLink - Combination therapy of Epidermal Growth Factor and Growth Hormone-Releasing Hexapeptide in acute ischemic stroke: a phase I/II non-blinded, randomized clinical trial
Rodriguez Blanco S, Verdecia Jarque M, Fernandez Mayola M, et al. (2024). Frontiers in NeurologyADOI - The Prohibited List 2025 — World Anti-Doping Code International Standard
World Anti-Doping Agency (2024). WADA (World Anti-Doping Agency)ALink
Community Sources
Storage
Unopened
Lyophilized powder: store at 2–8 °C (refrigerator) or at -20 °C for long-term storage. Protection from light required.
Opened
After reconstitution with bacteriostatic water: store at 2–8 °C, use within 28–30 days. Do not freeze after reconstitution.
Notes
Peptides are sensitive to heat, light, and repeated freeze/thaw cycles. Sterility must be strictly maintained during reconstitution.