GHRP-6 Acetate: Research Peptide Profile

GHRP-6 (Growth Hormone-Releasing Peptide-6) is a synthetic hexapeptide that functions as a potent agonist of the growth hormone secretagogue receptor (GHS-R), also known as the ghrelin receptor . This profile provides essential information for researchers working with this compound.

What is GHRP-6?

GHRP-6 is a first-generation peptidyl growth hormone secretagogue with the sequence His-D-Trp-Ala-Trp-D-Phe-Lys-NH₂ . It was developed to stimulate growth hormone release through a mechanism distinct from endogenous growth hormone-releasing hormone (GHRH) . The compound is known for its well-documented orexigenic (appetite-stimulating) and cardioprotective properties .

Key Identifiers:

• CAS Number: 145177-42-0 

• Molecular Formula: C₄₆H₅₆N₁₂O₆ (acetate salt: C₅₂H₆₈N₁₂O₁₂) 

• Molecular Weight: 1053.2 g/mol (acetate salt) 

• Purity: Typically ≥98% for research-grade material

• Status: Research compound only; not FDA-approved for human use

Mechanism of Action

GHRP-6 functions through several well-characterized pathways:

GHS-R1a Binding:

• GHRP-6 binds to the growth hormone secretagogue receptor type 1a (GHS-R1a), which is also the receptor for ghrelin 

• It inhibits binding of the non-peptide agonist MK-0677 with a Ki of 1.9 nM 

• It stimulates intracellular calcium mobilization (EC₅₀ = 4.5 nM) and inositol phosphate production (EC₅₀ = 0.83 nM) 

GH Release:

• Acts directly on somatotrophs in the pituitary to cause GH release 

• Potentiates the actions of GHRH 

• Functions as a functional antagonist of somatostatin 

• Synergizes with GHRH to produce additive GH release 

Neuroendocrine Effects:

• Unlike ipamorelin, GHRP-6 reliably elevates ACTH and cortisol levels 

• This makes it a valuable tool for hypothalamic-pituitary-adrenal (HPA) axis research 

• The ACTH response is variable and depends on prevailing HPA axis activity 

Alternative Receptor Binding:

• GHRP-6 also binds to the ectodomain of the CD36 receptor 

• This binding is thought to contribute to its cardioprotective effects 

Research Applications

Lung Injury and Fibrosis Research

A 2026 study published in International Immunopharmacology demonstrated that GHRP-6 ameliorated acute lung injury and prevented progression to interstitial fibrosis in mouse models . Key findings include:

• Reduced neutrophilic alveolitis in the acute scenario 

• Improved lung compliance and alveolar-capillary barrier integrity 

• Reduced serum interleukin-1β levels 

• Preserved lung parenchymal integrity with minimal collagen accumulation in chronic injury 

• This was the first assessment of GHRP-6’s protective role in lung damage models 

Cardioprotection Research

GHRP-6 has demonstrated cardioprotective effects in multiple experimental scenarios :

• Prevention of doxorubicin-induced myocardial damage 

• Sustained cellular antioxidant defense 

• Upregulation of prosurvival gene Bcl-2 

• Preservation of cardiomyocyte mitochondrial integrity 

• Anti-fibrotic effects in cardiac tissue 

Growth Hormone Research

GHRP-6 is a standard tool for studying GH secretion:

• In Vitro: Stimulates GH release from pituitary cells 

• In Vivo: Dose-dependent GH release in animal models 

• Comparative Potency: GHRP-6 demonstrates higher maximal efficacy (Emax = 74 ± 7 ng GH/ml) compared to GHRP-2, though it is less potent (ED₅₀ = 3.9 ± 1.4 nmol/kg) 

Orexigenic Studies

GHRP-6 stimulates food intake . This effect is mediated through central mechanisms, as demonstrated by intracerebroventricular administration in rats .

Liver Fibrosis Research

GHRP-6 has shown anti-fibrotic effects in experimental models of liver cirrhosis .

Regulatory Status and Legal Considerations

FDA and Compounding Status

As of June 2026, GHRP-6 remains restricted on the FDA’s Category 2 list :

• Not legally compoundable by licensed pharmacies under Section 503A

• Not FDA-approved for any human therapeutic indication

• While many peptides are expected to return to Category 1 following the February 2026 HHS announcement, GHRP-2, GHRP-6, Ibutamoren mesylate, and Kisspeptin-10 remain restricted 

Key Clarification: Category 2 status governs compounding legality only. It does not confer FDA approval, validated indications, or standardized dosing .

WADA Prohibited Status

GHRP-6 is listed as a prohibited substance by the World Anti-Doping Agency (WADA) . Detection methods using UPLC-MS/MS have achieved limits of detection of 0.5 ng/mL for GHRP-6 in urine .

Research-Use Only

GHRP-6 is available exclusively from authorized research suppliers for in vitro and preclinical research use only. It is not for human consumption .

Comparative Data: GHRP-6 vs. GHRP-2 vs. Ipamorelin

Data from swine studies 

GHRP-6 is selected over GHRP-2 when maximal GH secretion amplitude is the experimental endpoint, rather than high receptor potency . It is selected over ipamorelin when experimental design requires concurrent activation of the HPA axis .

Reconstitution & Handling for Research

General Handling:

• Solubility: Soluble in DMF, DMSO, and PBS (pH 7.2) 

• Storage: Lyophilized powder: -20°C 

• Stock Solutions: Store at -80°C (up to 6 months) or -20°C (up to 1 month) 

• Avoid Repeated Freeze-Thaw: Divide into aliquots to prevent degradation

• Shipping: Stability at ambient temperature for several days

Frequently Asked Questions

What is GHRP-6?

GHRP-6 is a synthetic hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH₂) that binds to the ghrelin receptor (GHS-R1a) and stimulates growth hormone release .

How does GHRP-6 work?

It binds to GHS-R1a on the pituitary and hypothalamus, triggering GH release through calcium influx and other signaling pathways. It potentiates GHRH action and functionally antagonizes somatostatin .

Is GHRP-6 FDA-approved?

No. GHRP-6 is not FDA-approved for any indication. It remains restricted under FDA Category 2 and is not legally compoundable .

What does research show about GHRP-6?

Recent research demonstrates protective effects in lung injury, cardioprotection against doxorubicin toxicity, anti-fibrotic effects, and robust GH release . It is also a well-established orexigenic agent .

How does GHRP-6 differ from GHRP-2?

GHRP-6 has lower potency (higher ED₅₀) but greater maximal efficacy (higher Emax) than GHRP-2. It also elevates ACTH and cortisol, while both share similar receptor binding .

How does GHRP-6 differ from ipamorelin?

Unlike ipamorelin, GHRP-6 significantly elevates ACTH and cortisol levels. This makes GHRP-6 appropriate for HPA axis research and stress-response studies, whereas ipamorelin is preferred for GH-specific studies with minimal corticosteroid interference .

Is GHRP-6 banned in sports?

Yes. GHRP-6 is a prohibited substance under WADA regulations .

Can I buy GHRP-6?

GHRP-6 is available from research suppliers for laboratory use only. It is not legally marketed for human consumption .