Research Comparison
GHRP-2 vs IGF-1 LR3 (Long R3 IGF-1)
A side-by-side research comparison of GHRP-2 and IGF-1 LR3 (Long R3 IGF-1) drawn from Cobalt Peptides' peptide database records.
GHRP-2
GHRP-2 (Growth Hormone Releasing Peptide-2) is a synthetic hexapeptide belonging to the growth hormone secretagogue (GHS) class. It stimulates the release of endogenous growth hormone (GH) primarily through activation of the ghrelin receptor (GHS-R1a) in the hypothalamus and pituitary. Unlike GHRH analogs, GHRP-2 acts via a distinct pathway, making it highly synergistic when combined with GHRH-based peptides. It is widely used in research to investigate growth hormone pulsatility, appetite signalling, and metabolic regulation.
IGF-1 LR3 (Long R3 IGF-1)
IGF-1 LR3 is a synthetic 83-amino acid analog of insulin-like growth factor-1 (IGF-1), modified with an arginine substitution at position 3 and an extended N-terminal sequence. These modifications significantly reduce binding to IGF-binding proteins (IGFBPs), resulting in prolonged circulation and increased bioavailability. Unlike native IGF-1, which has a short half-life, IGF-1 LR3 exhibits a substantially extended half-life (~20–30 hours), allowing sustained activation of IGF-1 receptors. Despite its potency and widespread research use, it has never been approved for human use and lacks clinical trial data, remaining strictly a research compound.