GHRP-2

GHRP‑2

What is GHRP‑2?

GHRP‑2 (growth hormone‑releasing peptide‑2, pralmorelin) is a synthetic hexapeptide that acts as a potent agonist at the ghrelin / growth hormone secretagogue receptor (GHS‑R1a). It was the first compound in this class to enter clinical development and is widely used as:

• A test peptide for assessing growth hormone (GH) deficiency
• A research tool to study the GH/IGF‑1 axis and ghrelin signaling

In human and animal research, GHRP‑2 has been shown to stimulate GH release and to influence appetite, muscle protein balance, cardiovascular function, immune parameters, sleep architecture, and pain perception. It has demonstrated bioactivity after oral, sublingual, and parenteral administration in study settings.

GHRP‑2 Structure

• Peptide type: Synthetic hexapeptide ghrelin receptor agonist
• Sequence: H–D‑Ala–D‑2‑Nal–Ala–Trp–D‑Phe–Lys–NH₂
• Molecular formula: C₄₅

Documented Research Effects

1. Muscle Structure: Protection and Enhancement

Experimental work in livestock and cellular models indicates that GHRP‑2 supports skeletal muscle in two ways:

• Enhances protein deposition: In growth‑retarded yaks exposed to harsh environmental and nutritional conditions, GHRP‑2 improved growth performance and muscle protein accretion by activating the somatotropic (GH/IGF‑1) axis undefined +1 .
• Reduces protein degradation: In myocytes, GHRP‑2 directly suppresses the expression of atrogin‑1 and MuRF1—key ubiquitin ligases that drive muscle atrophy .

Together, these actions suggest that GHRP‑2 can help maintain or increase lean mass under catabolic stress, making it useful in research on muscle atrophy, chronic disease, and growth retardation models.

2. Appetite Stimulation

GHRP‑2 reliably increases short‑term food intake in:

• Healthy men
• Obese subjects, who remain responsive to ghrelin receptor agonism

Because appetite loss is common in chronic disease and cachexia, GHRP‑2 is a valuable tool for studying ghrelin‑mediated control of hunger, satiety, and overall energy balance.

3. Potential Cardiovascular Protection

Cardiac and vascular research has shown that GHRP‑2 and related peptides:

• Reduce cardiomyocyte apoptosis, likely through protective effects on mitochondrial function .
• Act via specific receptors in the heart distinct from the pituitary GHS‑R, indicating additional cardiac targets for this peptide family .

These findings support the use of GHRP‑2 in preclinical models of ischemia, heart failure, and myocardial protection.

4. Immune and Thymic Effects

Age‑related decline in thymic function contributes to reduced T‑cell production and weaker adaptive immunity. Ghrelin receptor agonists, including GHRP‑2, have been associated with:

• Thymic stimulation and partial rejuvenation in aging models
• Increased T‑cell output and repertoire diversity

GHRP‑2 thereby serves as a research tool to explore endocrine–immune interactions, immune aging, infection resistance, and tumor surveillance.

5. Sleep Architecture and Quality

Growth hormone secretagogues have notable effects on sleep. For example, the ghrelin agonist MK‑677 (same receptor class as GHRP‑2) has been documented to:

• Increase deep slow‑wave sleep (stages 3 and 4)
• Improve overall sleep continuity and quality in human studies

While these specific data are from MK‑677, they highlight the broader role of ghrelin receptor activation and GH release in sleep regulation. GHRP‑2 is used in research exploring how GHS‑R agonism affects sleep phases, cognitive performance, blood pressure, healing, and energy levels.

6. Pain Perception and Opioid Receptor Interaction

In mouse models:

• Supraspinal administration of GHRP‑2 produces antinociceptive (pain‑reducing) effects .
• These effects are reversed by opioid receptor antagonists, indicating that GHRP‑2 engages opioid pathways at the supraspinal level .

GHRP‑2 appears to have a degree of selectivity for opioid receptor subtypes associated mainly with analgesia and sedation, making it a useful probe for designing and testing new analgesic strategies that may reduce typical opioid side effects in preclinical research.

Safety, Handling, and Intended Use

• Animal research indicates minimal to moderate side effects, with good subcutaneous bioavailability and variable oral activity depending on species undefined +1 .
• Reported dose levels in animal models do not translate to humans and must not be extrapolated.

GHRP‑2 from Peptide Sciences is supplied solely for laboratory research and educational purposes. It is not a drug, food, cosmetic, or supplement and must not be used for human or veterinary diagnosis, treatment, or consumption. Purchase and handling are restricted to appropriately qualified and licensed research professionals.

Article Author

This overview was researched, edited, and organized by Dr. Logan, M.D., who holds a medical degree from Case Western Reserve University School of Medicine and a B.S. in Molecular Biology.

Scientific Acknowledgment

Jean‑Alain Fehrentz, Ph.D., a chemist trained at the University of Nancy and long‑time researcher in Montpellier, has made major contributions to:

• Peptide synthesis and peptidomimetics
• Enzyme inhibitor design
• Ghrelin receptor ligands and growth hormone secretagogues

He is cited solely to recognize his scientific work related to GHRP‑2 and similar ligands. This reference does not imply endorsement, recommendation, or any professional relationship with Peptide Sciences or this product.

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