Ipamorelin vs GHRP-2 — How the Two Secretagogues Compare
Ipamorelin and GHRP-2 are both synthetic growth hormone secretagogue research peptides, and they are often compared. They are structurally different — a pentapeptide versus a hexapeptide — and this page sets out the factual differences for researchers.
Last updated: 2026-08-21 · By: Index Peptides technical team
| Ipamorelin | GHRP-2 | |
|---|---|---|
| Structure | Pentapeptide (5 amino acids) | Hexapeptide (6 amino acids) |
| CAS number | 170851-70-4 | 158861-67-7 |
| Molecular weight | ~711.9 g/mol | ~818.0 g/mol |
| Research context | GH secretagogue research | GH secretagogue research |
| Index Peptides formats | 5mg | 10mg |
Different structures
Ipamorelin is a synthetic pentapeptide (Aib-His-D-2-Nal-D-Phe-Lys-NH2); GHRP-2 is a synthetic hexapeptide (D-Ala-D-2-Nal-Ala-Trp-D-Phe-Lys-NH2). Both are studied as growth hormone secretagogues, but they are distinct compounds with different CAS numbers and molecular weights.
Chemistry
Ipamorelin is CAS 170851-70-4 at approximately 711.9 g/mol. GHRP-2 is CAS 158861-67-7 at approximately 818.0 g/mol. Both are supplied as lyophilised powders and are commonly handled as acetate salts; the exact form is recorded on each batch's certificate of analysis.
Research literature
Both peptides appear in preclinical receptor-pharmacology literature as growth hormone secretagogue receptor ligands, typically in in-vitro models. This page describes the materials and their documentation only.
Supply status
Index Peptides supplies both strictly as research chemicals for in-vitro laboratory research. Products are sold exclusively to qualified researchers and licensed laboratories. Neither is for human or veterinary use.
Frequently asked questions
Which is 'better' — ipamorelin or GHRP-2?
Neither is 'better'. They are different peptides from different structures, and Index Peptides takes no position on any application. The documentation — identity, purity and batch record — is what matters when comparing suppliers.
Are ipamorelin and GHRP-2 the same compound?
No. Ipamorelin is a pentapeptide (CAS 170851-70-4) and GHRP-2 is a hexapeptide (CAS 158861-67-7), with different sequences and molecular weights.
How do I verify the identity of each?
Review the published certificate for the exact lot, including the laboratory, report date and analytical results actually reported. HPLC purity alone does not confirm LC-MS identity. Contact us before ordering if a required result is not published.
References
Research use only. Not for human or animal consumption.