Guide

GHRP-2 vs GHRP-6 vs ipamorelin

Three ghrelin receptor agonists that differ by one design goal: selectivity. Sequences, masses, and what separates a selective agonist from a broad one.

Published September 4, 2026

Four peptides at one receptor. What separates them is how selective each one is.

Peptide	Vial sizes	From
Ipamorelin	5mg	$59.99 CAD
GHRP-2	5mg	$24.99 CAD
GHRP-6	5mg	$24.99 CAD
Hexarelin	Single size	$54.99 CAD

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Selectivity

GHRP-6 came first, a hexapeptide that binds the ghrelin receptor. GHRP-2 followed as a more potent hexapeptide at the same target. Hexarelin is a third in the same shape.

All three are studied for activity beyond the growth-hormone axis in research models, which is either the point or the problem depending on what you are studying. If you want a clean readout at one receptor, spillover is noise.

Ipamorelin was designed to remove that noise. It is a pentapeptide, one residue shorter and about a hundred grams per mole lighter, built to act at the ghrelin receptor with far less activity elsewhere. That is why it appears in blends where the other variable has to stay fixed.

The four, by the numbers

	Residues	Formula	Molecular weight	CAS
Ipamorelin	5	C38H49N9O5	711.85 g/mol	170851-70-4
GHRP-2	6	C45H55N9O6	817.96 g/mol	158861-67-7
GHRP-6	6	C46H56N12O6	873.01 g/mol	87616-84-0
Hexarelin	6	C47H58N12O6	887.02 g/mol	140703-51-1

GHRP-6 and hexarelin are 14 g/mol apart. That is close, but a mass-spec result reads to well under one gram per mole at this size, so the two are still distinguishable on a report. Check the observed mass against the expected one before assuming a vial is what the label says.

Small peptides, big molar numbers

These are the lightest peptides in the catalog outside the tripeptides, and that shows up in the molar column. A 5 mg vial of ipamorelin is about 7 micromoles; a 5 mg vial of a 5,000 g/mol peptide is about 1. Seven times the molecules for the same label.

Vial	1 mL	2 mL	3 mL	5 mL
5 mg	5 mg/mL7.02 mM	2.5 mg/mL3.51 mM	1.67 mg/mL2.34 mM	1 mg/mL1.4 mM

Ipamorelin vial sizes we sell, at four diluent volumes. Molarity uses 711.85 g/mol. Other volumes

Pairing with a GHRH analog

A ghrelin agonist and a GHRH analog hit different receptors, which is why protocols study them together rather than choosing between them. The CJC-1295 no-DAC and ipamorelin blend is that pairing in one vial, and CJC-1295 DAC vs no-DAC explains why the no-DAC form is the one used.

In one line

Ipamorelin is the selective one and the smallest. GHRP-2 and GHRP-6 are broader hexapeptides, and hexarelin is a fourth in that shape. By mass: 712, 818, 873, 887.

For research use only. Not for human or animal consumption.

Frequently asked questions

What is the difference between GHRP-2, GHRP-6 and ipamorelin?+

Selectivity. All three are ghrelin receptor agonists. GHRP-6 and GHRP-2 are hexapeptides that also show activity at other endocrine pathways in research models. Ipamorelin is a pentapeptide designed to act at the ghrelin receptor with far less of that spillover.

Is ipamorelin a GHRP?+

Functionally yes, it is a growth hormone secretagogue acting at the same receptor. Structurally it is a different and shorter molecule: five residues at 712 g/mol against six residues at 818 and 873 for GHRP-2 and GHRP-6.

Where does hexarelin fit?+

It is a fourth hexapeptide in the same family, at 887 g/mol, studied in growth-hormone-axis and cardiac research models. It sits closest to GHRP-6 structurally.

Do these get paired with a GHRH analog?+

In research protocols, often. A ghrelin agonist and a GHRH analog act on different receptors, which is why the two are studied together. We sell one such pairing as a single blended vial.

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