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Batch tested · UK stocked

HelixCore
Compound profile26 May 2026·10 min read

CJC-1295, Ipamorelin, GHRP-6: how the GH secretagogues compare

A structural and receptor-level comparison of the three most common GH secretagogue research peptides — sequence, receptor target, half-life, and published experimental context.

Growth hormone secretagogues are one of the larger families of research peptides — and one where the differences between the named compounds matter at the receptor level. They are often referenced interchangeably as "GHRPs", but receptor selectivity, half-life, and downstream signalling differ enough that the three are not equivalent for in-vitro receptor-modelling work.

This article compares the three most commonly studied: CJC-1295 (no DAC),Ipamorelin, and GHRP-6. A summary table appears at the end.

Two families, one outcome

Growth hormone (GH) release from the pituitary is governed by two independent signalling axes. Understanding which axis a compound acts on is the most important distinction.

GHRH analogues

Growth hormone-releasing hormone is a hypothalamic peptide that binds the GHRH receptor on pituitary somatotrophs and triggers GH release. Synthetic GHRH analogues (like CJC-1295) preserve this pathway.

GHRPs (ghrelin mimetics)

Growth hormone releasing peptides act on a separate receptor (GHS-R1a, the ghrelin receptor). They also trigger GH release but via a different mechanism. Published in-vitro work has reported additive or synergistic effects when GHRH and ghrelin-axis pathways are studied together. Ipamorelin and GHRP-6 are both in this family.

CJC-1295 (no DAC)

Also called Mod GRF (1-29). It's a synthetic fragment of GHRH (amino acids 1 through 29 of the natural hormone) with four amino acid substitutions that protect it from rapid proteolytic degradation. The "no DAC" suffix is important — there's a related compound called CJC-1295 with DAC (Drug Affinity Complex) that has a much longer half-life by binding to albumin. The two have very different pharmacokinetic profiles and should not be confused.

Receptor

GHRH receptor (the GHRH axis).

Half-life

Short — around 30 minutes for CJC-1295 no DAC. The short half-life means receptor occupancy is brief, which preserves pulsatile signalling patterns in models where that matters.

Typical experimental context

Published preclinical work has used CJC-1295 (no DAC) in receptor-binding and pulsatile-release model systems. The short half-life is the distinguishing characteristic versus the longer-acting CJC-1295 with DAC.

Ipamorelin

A synthetic pentapeptide. Ipamorelin is the most receptor-specific of the GHRPs: it acts on GHS-R1a (ghrelin receptor) with high selectivity and very little cross-activity at the receptors that govern cortisol or prolactin release.

Receptor

GHS-R1a (the ghrelin axis).

Half-life

Approximately 2 hours.

Typical experimental context

Published work has used Ipamorelin in receptor-selectivity studies where ghrelin-axis activity is investigated without significant cortisol or prolactin crosstalk. It is the most receptor-specific of the GHRPs in the published literature.

GHRP-6

The oldest of the three — a hexapeptide first reported in the late 1980s. It also acts on GHS-R1a, with less receptor selectivity than Ipamorelin. The published literature notes some cortisol and prolactin crosstalk in animal models, alongside its activity at the ghrelin receptor.

Receptor

GHS-R1a — less selective than Ipamorelin.

Half-life

Short — approximately 15–60 minutes depending on study.

Typical experimental context

GHRP-6 features in the older ghrelin-receptor literature and in comparative studies that include receptor crosstalk as a variable of interest.

At a glance

Reference table. Half-lives are approximate and vary across studies.

  • CJC-1295 (no DAC): GHRH receptor · ~30 min half-life · short receptor occupancy
  • Ipamorelin: GHS-R1a (selective) · ~2 hr half-life · minimal cortisol/prolactin crosstalk in published models
  • GHRP-6: GHS-R1a (less selective) · ~15–60 min half-life · cortisol/prolactin crosstalk reported in published models

Choosing between them for an in-vitro model

Three structural questions usually decide which compound is most relevant for a given experimental design:

  1. Which receptor pathway is being modelled? GHRH receptor work calls for CJC-1295; ghrelin-receptor work calls for Ipamorelin or GHRP-6. Comparative crosstalk work may use one of each.
  2. Is receptor selectivity a variable of interest? Ipamorelin is the most receptor-selective in the published literature. GHRP-6 reports broader receptor crosstalk, which can be useful or confounding depending on the question.
  3. Is pulsatile or sustained receptor occupancy required? Short half-lives preserve pulsatile signalling profiles; the DAC-modified version of CJC-1295 (not stocked here) produces sustained occupancy, which is a different experimental setup entirely.

Specifications & sourcing

All three are typically sold as lyophilised acetate salts. CJC-1295 no DAC and Ipamorelin are commonly available in 2mg and 5mg vials; GHRP-6 in 5mg. 98%+ purity is the standard for research-grade material — anything less can introduce impurity peaks that mess up downstream analytical work.

HelixCore stocks all three, sourced from supply chains that operate independent third-party batch testing as standard. Browse the Growth Factor Research category or the CJC-1295 + Ipamorelin research blend.