Summary

GHRP-2 (pralmorelin) is a synthetic hexapeptide that acts as a growth hormone secretagogue, binding to the ghrelin receptor (GHS-R1a) to stimulate the pituitary gland to release growth hormone. It was among the first-generation GHRPs and has been studied in human clinical trials for growth hormone deficiency and cachexia. Research suggests it increases both GH and IGF-1 levels, though evidence for body composition effects in healthy adults remains limited. GHRP-2 is not licensed as a medicine in the UK and sits in a grey area for research purchase.

Mechanism

GHRP-2 is a synthetic hexapeptide that acts as an agonist at the growth hormone secretagogue receptor 1a (GHS-R1a), also known as the ghrelin receptor. Binding to this receptor on somatotroph cells in the anterior pituitary gland triggers a signalling cascade (via Gq/11 proteins and inositol triphosphate) that stimulates growth hormone release through both direct pituitary action and indirect effects on the hypothalamus. Unlike GHRH, which acts at the GHRH receptor, GHRP-2 acts at a distinct receptor, allowing for synergistic GH release when both pathways are activated simultaneously.

Evidence base

GHRP-2 has a moderate evidence base supported by human clinical trials, primarily in growth hormone deficiency (approved for diagnostic use in Japan) and cachexia (COPD, cancer). Dose-response and pharmacokinetic data exist from healthy adult studies. However, there are no large-scale, long-term trials in healthy adults for body composition or anti-ageing purposes, and evidence outside clinical populations should be considered preliminary.

Protocols

Research literature describes subcutaneous administration at 100–300 mcg per dose, 1–3 times daily, typically cycled 4–8 weeks on with time off to mitigate tachyphylaxis. A '5 days on, 2 days off' schedule is also commonly discussed. Combination with a GHRH analogue (e.g., CJC-1295 or modified GRF 1-29) is a frequent research paradigm due to demonstrated synergy. All doses are presented for research context only — GHRP-2 is not licensed for human use in the UK.

GHRP-2 is not licensed as a medicine in the UK and is not a controlled substance. It sits in a grey area: purchasable as a research chemical for legitimate laboratory use, but not licensed for human consumption. The MHRA has issued warnings about unlicensed peptide injections sold online. Importing for personal use may attract Border Force scrutiny.

Vendor notes

See our vetted UK vendor pages for suppliers offering GHRP-2 with appropriate purity testing and COA documentation.

References

  1. Shimatsu A, et al. "Clinical application of pralmorelin (GHRP-2) for diagnostic test of growth hormone deficiency." Nippon Rinsho (2002). PMID: 12380906.
  2. Deboer MD, et al. "Growth hormone releasing peptide-2 (GHRP-2) for the treatment of cachexia." Current Opinion in Clinical Nutrition and Metabolic Care (2014). doi: 10.1097/MCO.0000000000000090.
  3. Bowers CY, et al. "Growth hormone releasing peptide-2 (GHRP-2): a potent GH-releasing peptide." Journal of Pediatric Endocrinology and Metabolism (2001). PMID: 11758247.
  4. Raun K, et al. "Interaction of GHRP and GHRH on GH release in conscious rats." European Journal of Endocrinology (1998). PMID: 9658434.
  5. Medicines and Healthcare products Regulatory Agency (MHRA). Warnings regarding unlicensed peptide and weight-loss injections. gov.uk (accessed 2025).