GHRP-6 vs GHRP-2 - How the Two Hexapeptides Compare
GHRP-6 and GHRP-2 are the two growth hormone releasing peptide hexapeptides in the Index Peptides catalogue, and they are the pair most often compared. They share the same research lineage but are structurally distinct compounds, and this page sets out the factual differences for researchers.
Last updated: 2026-08-21 · By: Index Peptides technical team
| GHRP-6 | GHRP-2 | |
|---|---|---|
| Structure | Hexapeptide (6 amino acids) | Hexapeptide (6 amino acids) |
| Sequence | His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 | D-Ala-D-2-Nal-Ala-Trp-D-Phe-Lys-NH2 |
| CAS number | 87616-84-0 | 158861-67-7 |
| Molecular formula | C46H56N12O6 | C45H55N9O6 |
| Molecular weight | 873.0 g/mol | 818.0 g/mol |
| Research context | GH secretagogue research | GH secretagogue research |
| Index Peptides formats | 10mg | 10mg |
Different structures, shared lineage
GHRP-6 (CAS 87616-84-0) and GHRP-2 (CAS 158861-67-7) both belong to the growth hormone releasing peptide (GHRP) family, developed from the same research programme in the 1980s. GHRP-6 is the older of the two. Both are hexapeptides, but they are distinct molecules: GHRP-6 runs His-D-Trp-Ala-Trp-D-Phe-Lys-NH2, while GHRP-2 runs D-Ala-D-2-Nal-Ala-Trp-D-Phe-Lys-NH2, with a D-2-naphthylalanine in place of the second tryptophan and a D-alanine at the N-terminus.
Chemistry
GHRP-6 is CAS 87616-84-0, molecular formula C46H56N12O6, approximately 873.0 g/mol. GHRP-2 is CAS 158861-67-7, molecular formula C45H55N9O6, approximately 818.0 g/mol. Both are supplied as lyophilised powders and are commonly handled as salts; the exact form and counter-ion are recorded on each batch's certificate of analysis.
Research literature
Both peptides appear in preclinical receptor-pharmacology literature as ligands of the ghrelin receptor (GHS-R), typically in in-vitro models. GHRP-6 has the longer publication history of the two. 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' - GHRP-6 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 GHRP-6 and GHRP-2 the same compound?
No. They share a research lineage and both are hexapeptides, but they have different sequences, CAS numbers and molecular weights. The two names are not interchangeable.
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.