GHRP-2

Chemical Profile
- Molecular Formula: C₄₅H₅₅N₉O₆
- Molecular Weight: 817.97 g/mol
- Alternate Name: Pralmorelin

Growth Hormone Secretion:
GHRP-2 significantly enhances GH release. Studies report up to a 181-fold spike in GH, a 47-fold increase in pulsatile secretion over a 2.5-hour period, and sustained elevations in IGF-1.
- Appetite Stimulation:
Murine models demonstrate a ~36% increase in food intake compared to controls, with elevated energy intake per kilogram of body weight and increased GH area-under-curve metrics.
- Muscle Preservation:
In thermal injury models, GHRP-2 reduces proinflammatory markers (e.g., IL-6, MuRF-1, MAFbx) and muscle protein degradation, indicating a muscle-sparing effect and potential for supporting weight gain.
- Antioxidative and Anti-inflammatory Actions:
GHRP-2 shows affinity for CD36, limiting OxLDL uptake. In ApoE(-/-) mice, chronic exposure elevates IGF-I by 1.2–1.6-fold, reduces circulating interferon-gamma by ~66%, and lowers aortic superoxide production.
Vascular Gene Expression & Cytoprotection:
GHRP-2 reduces aortic 12/15-lipoxygenase gene expression by approximately 92% and downregulates interferon-gamma and macrophage migration inhibitory factor. In cultured aortic smooth muscle cells, it attenuates OxLDL-induced peroxide production, maintains IGF-I receptor expression, and potentially inhibits apoptosis. In macrophages, GHRP-2 diminishes lipid accumulation, highlighting its antioxidative and antiatherogenic properties.
Anti-inflammatory Activity:
In murine models of acute lung injury, GHRP-2 significantly reduces lung edema, neutrophil infiltration, and pro-inflammatory cytokine levels by suppressing NF-κB activation, thereby mitigating inflammatory cascades.
GH Deficiency Diagnostics:
In GH deficiency models, following overnight fasting, GHRP-2 induces a reproducible GH peak within one hour of administration. Comparative studies reveal that in both normal and GH-deficient models (assessed via the insulin tolerance test), GHRP-2 alone—even when later combined with GHRH—elicits a marked GH secretion, affirming its utility as a diagnostic tool.
- Vascular Gene Expression & Cytoprotection:
GHRP-2 reduces aortic 12/15-lipoxygenase gene expression by approximately 92% and downregulates interferon-gamma and macrophage migration inhibitory factor. In cultured aortic smooth muscle cells, it attenuates OxLDL-induced peroxide production, maintains IGF-I receptor expression, and potentially inhibits apoptosis. In macrophages, GHRP-2 diminishes lipid accumulation, highlighting its antioxidative and antiatherogenic properties.
- Anti-inflammatory Activity:
In murine models of acute lung injury, GHRP-2 significantly reduces lung edema, neutrophil infiltration, and pro-inflammatory cytokine levels by suppressing NF-κB activation, thereby mitigating inflammatory cascades.
- GH Deficiency Diagnostics:
In GH deficiency models, following overnight fasting, GHRP-2 induces a reproducible GH peak within one hour of administration. Comparative studies reveal that in both normal and GH-deficient models (assessed via the insulin tolerance test), GHRP-2 alone—even when later combined with GHRH—elicits a marked GH secretion, affirming its utility as a diagnostic tool.
- Hormonal Axis Modulation (Combination Studies):
In models of prolonged hypo-somatotropism, hypogonadism, and hypothyroidism, the co-administration of GHRP-2 with TRH and GnRH (administered hourly or every 90 minutes) produces the highest activation of the GH, TSH, and LH axes. This combination amplifies metabolic and endocrine responses beyond those achieved by GHRP-2 alone or with TRH.

Asad Rahim, Stephen M. Shalet, in Growth Hormone Secretagogues, 1999. Does desensitization to growth hormone secretagogues occur? https://www.sciencedirect.com/topics/medicine-and-dentistry/pralmorelin

Chihara K, Shimatsu A, Hizuka N, Tanaka T, Seino Y, Katofor Y; KP-102 Study Group. A simple diagnostic test using GH-releasing peptide-2 in adult GH deficiency. Eur J Endocrinol. 2007 Jul;157(1):19-27. doi: 10.1530/EJE-07-0066. https://pubmed.ncbi.nlm.nih.gov/17609397/

Veldhuis, J. D., Keenan, D. M., Bailey, J. N., Adeniji, A. M., Miles, J. M., & Bowers, C. Y. (2009). Novel relationships of age, visceral adiposity, insulin-like growth factor (IGF)-I and IGF binding protein concentrations to growth hormone (GH) releasing-hormone and GH releasing-peptide efficacies in men during experimental hypogonadal clamp. The Journal of clinical endocrinology and metabolism, 94(6), 2137–2143. https://doi.org/10.1210/jc.2009-0136