CJC-1295 + Ipamorelin : the GH secretagogue duo in research

The hypothalamic-pituitary axis of GH: a reminder

To understand the benefit of the CJC-1295 + Ipamorelin combination, it is first necessary to recall the physiological regulation of growth hormone (GH, somatotropin) secretion:

• The hypothalamus releases the GHRH (Growth Hormone-Releasing Hormone) which stimulates the pituitary gland to secrete GH
• La somatostatin (GHIH) inhibits GH secretion — natural brake
• La ghreline (hunger hormone) activates GHSR-1a receptors and potentiates GH secretion, while also inhibiting somatostatin
• The GH released into the blood stimulates the production ofIGF-1 in the liver, mediator of most anabolic effects

The CJC-1295 + Ipamorelin strategy involves activating the two stimulator arms of this system simultaneously: the GHRH arm (via CJC-1295) and the ghrelin arm (via Ipamorelin).

CJC-1295: Long-acting GHRH analogue

Structure and pharmacology

Le CJC-1295 is a synthetic analogue of natural GHRH (44 amino acids) with several amino acid substitutions that improve its stability against proteases. Two versions exist:

• CJC-1295 without DAC (Drug Affinity Complex): half-life of 30 minutes, GH secretion profile more "pulsatile" and closer to physiological
• CJC-1295 with DAC (Mod GRF 1-29): binds covalently to serum albumin, extended half-life of 6-8 days, prolonged elevation of basal GH

For research on physiological secretion profiles, the CJC-1295 without DAC is generally preferred because it better mimics the natural pulsatility of GH.

Ipamorelin: ultra-selective ghrelin agonist

Why is Ipamorelin among the GHRPs?

Ghrelin-type GH secretagogues (GHRPs) include several molecules: GHRP-2, GHRP-6, Hexarelin, Ipamorelin.Ipamorelin stands out due to its exceptional selectivity profile:

Ipamorelin stimulates GH secretion significantly without inducing a notable rise in cortisol (stress hormones), prolactin, or appetite — a unique selectivity property in its class, valuable for controlled scientific research.

The synergy of CJC-1295 + Ipamorelin

The combination of the two peptides exploits a documented pharmacological synergy:

• CJC-1295 activates the GHRH-R receptor on pituitary somatotropes → prepares the cell for a strong release of GH
• Ipamorelin activates the GHSR-1a receptor → triggers the release of GH et simultaneously suppresses somatostatin (brake released)
• The combination produces a release of GH 2 to 10 times higher to each peptide alone in rat and pig studies
• The release profile is pulsatile and physiological — no chronic basal elevation that would saturate the receptors

Effects of high GH on body composition

Increased GH secretion with CJC-1295 + Ipamorelin leads to elevated hepatic IGF-1. Documented effects of GH/IGF-1 on body composition include:

• Lipolysis: GH directly activates lipolysis in adipocytes, particularly visceral fat.
• Preservation of lean mass: IGF-1 has an anti-catabolic effect on muscle tissue
• Improved insulin sensitivity: with physiological doses of GH (paradoxical effects possible at high doses)
• Post-exercise recovery: Nocturnal GH (natural peak during deep sleep) is involved in muscle protein synthesis

CJC-1295 standalone (with DAC) — different profile

Le CJC-1295 with DAC (Drug Affinity Complex), also known as Mod GRF 1-29, generates a sustained elevation of GH and IGF-1 over several days. However, this chronic elevation profile is less physiological than pulsatile peaks and can induce GHRH-R receptor tachyphylaxis in the long term. For research purposes, the choice between the two formulations depends on the intended experimental model.

Ipamorelin alone — gastrointestinal tract research

Independently of its effects on GH, ipamorelin has shown direct effects on gastrointestinal motility in preclinical models—a property linked to ghrelin receptors present in the entero-nervous system. Clinical trials (Phase 2, Helsinn Healthcare) have explored ipamorelin in the context of postoperative ileus.

Technical specifications