CJC-1295 and Ipamorelin: Growth Hormone Secretagogue Research

The Growth Hormone Axis

Growth hormone (GH) secretion from the anterior pituitary is regulated by a push-pull mechanism:

• Stimulation: Growth hormone-releasing hormone (GHRH) from the hypothalamus
• Inhibition: Somatostatin, also from the hypothalamus
• Amplification: Ghrelin, primarily from the stomach, acts at the growth hormone secretagogue receptor (GHS-R)

GH secretion is pulsatile, with major pulses occurring during slow-wave sleep. Between pulses, somatostatin tone keeps GH levels low. This pulsatile pattern is essential for GH's anabolic and metabolic effects.

CJC-1295: Extended GHRH Analog

Structure and Design

CJC-1295 is a synthetic analog of GHRH(1-29) with four amino acid substitutions that confer:

• Increased receptor binding affinity
• Resistance to dipeptidyl peptidase-4 (DPP-4) degradation
• Extended half-life at the GHRH receptor

Mechanism

CJC-1295 binds to the GHRH receptor (GHRH-R) on somatotroph cells in the anterior pituitary. This Gs-coupled GPCR activates adenylyl cyclase, increasing intracellular cAMP, which triggers GH synthesis and secretion. Unlike native GHRH, CJC-1295's modifications allow prolonged receptor occupancy and sustained signaling.

CJC-1295 With DAC

The version including a Drug Affinity Complex (DAC) adds a maleimidopropionic acid linker that binds covalently to serum albumin. This albumin conjugation extends the circulating half-life from minutes to approximately 8 days, fundamentally changing the pharmacokinetic profile from acute to sustained GH elevation.

Ipamorelin: Selective GHS-R Agonist

Structure and Design

Ipamorelin (Aib-His-D-2-Nal-D-Phe-Lys-NH₂) is a synthetic pentapeptide with high selectivity for the GHS-R. It was designed to avoid the unwanted effects of earlier ghrelin mimetics (GHRP-2, GHRP-6) on cortisol and prolactin secretion.

Mechanism

Ipamorelin binds to and activates the GHS-R, a Gq-coupled GPCR that triggers phospholipase C activation, IP3-mediated calcium release, and GH secretion. The key advantage is selectivity: at research-appropriate doses, Ipamorelin does not significantly elevate ACTH, cortisol, or prolactin — unlike less selective GHS-R agonists.

Combined CJC-1295 + Ipamorelin Research

The combination leverages complementary mechanisms:

• CJC-1295 amplifies the GHRH signal at the somatotroph
• Ipamorelin suppresses somatostatin tone and provides direct GHS-R activation
• Together they produce a coordinated, amplified GH pulse
• This combination more closely replicates the natural synergistic action of GHRH and ghrelin

Research Applications

• GH pulsatility studies using frequent-sampling protocols
• IGF-1 regulation and downstream signaling
• Somatotroph cell culture models
• Metabolic effects of GH axis modulation
• Comparative pharmacology of GHRH analogs and GHS-R agonists

Malice Research Lab supplies CJC-1295 with DAC (CD5) and CJC-1295 + Ipamorelin blend (CP10).