Research Comparison
IGF-1 LR3 (Long R3 IGF-1) vs Sermorelin
A side-by-side research comparison of IGF-1 LR3 (Long R3 IGF-1) and Sermorelin drawn from Cedar Peptides' peptide database records.
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.
Sermorelin
Sermorelin is a synthetic peptide corresponding to the first 29 amino acids of endogenous growth hormone-releasing hormone (GHRH 1–29), representing the shortest fully biologically active fragment. It functions as a physiologic stimulator of endogenous growth hormone (GH) secretion by acting on the anterior pituitary. Unlike exogenous GH administration, sermorelin preserves the natural pulsatile release of growth hormone, maintaining regulatory feedback mechanisms and reducing the risk of supraphysiological exposure. It is widely used in research contexts investigating growth hormone axis modulation, recovery, and metabolic regulation.
Reading a comparison
A comparison places two records side by side; it does not merge them. Each description above is drawn from that compound's own record, and the two were not necessarily characterised by the same methods, at the same time, or to the same level of detail. Before comparing any attribute, it is worth establishing that both records describe the substance you think they describe — names are not identifiers, and two entries sharing a name can differ in salt form, stereochemistry or the convention used to state a mass. Where a figure carries no method beside it, the comparison is between two reported numbers rather than between two measurements.