The Growth Hormone Axis
Growth hormone (GH) is secreted by the anterior pituitary gland in pulses — primarily during deep sleep and exercise. It drives muscle protein synthesis, fat metabolism, tissue repair, and IGF-1 production in the liver. As we age, both the frequency and amplitude of GH pulses decline significantly.
GH secretagogues are peptides that stimulate the pituitary to produce more GH — either by mimicking GHRH (Growth Hormone-Releasing Hormone) or ghrelin. CJC-1295 and Ipamorelin represent the two classes and are designed to work synergistically.
CJC-1295: The GHRH Analogue
CJC-1295 is a modified version of GHRH (1-29), the endogenous peptide that signals the pituitary to release GH. Two versions exist:
- CJC-1295 with DAC (Drug Affinity Complex) — binds to albumin in the blood, extending its half-life from minutes to 6–8 days. Produces a sustained baseline elevation of GH.
- CJC-1295 without DAC (also called Modified GRF 1-29) — short half-life (~30 minutes), produces a sharp, pulsatile GH release when injected. More closely mimics natural GHRH signalling.
The DAC version is commonly dosed weekly (1–2 mg/week), while the no-DAC version is dosed 2–3 times daily (100–200 mcg per dose) to align with the body's natural pulsatile rhythm.
Ipamorelin: The Clean Ghrelin Mimetic
Ipamorelin is a GHRP (Growth Hormone-Releasing Peptide) — it mimics ghrelin and acts on the ghrelin receptor (GHS-R) in the pituitary and hypothalamus to stimulate GH release. What makes Ipamorelin particularly popular is its selectivity:
- Minimal cortisol stimulation (unlike GHRP-2 or GHRP-6)
- Minimal prolactin stimulation
- Little to no appetite increase (unlike GHRP-6 which causes significant hunger)
- Clean GH pulse without the side effects of less selective GHRPs
Ipamorelin has a half-life of approximately 2 hours and is typically dosed at 200–300 mcg per injection, 2–3 times daily.
Why Stack Them?
GHRH (CJC-1295) and ghrelin mimetics (Ipamorelin) act through different receptors and have an additive — sometimes synergistic — effect on GH release. Research has shown that combining the two produces 3–5× more GH output than either peptide alone at the same doses.
The mechanism: GHRH increases the number of somatotrophs (GH-secreting cells) that respond to a stimulus, while ghrelin mimetics amplify the GH signal from each somatotroph. They prime and fire simultaneously.
Typical Protocol
Ipamorelin + CJC-1295 no-DAC (most common):
- 100–200 mcg CJC-1295 (no-DAC) + 200–300 mcg Ipamorelin, combined in one injection
- 2–3 injections per day: morning (fasted), pre-bed, optionally post-workout
- Inject on an empty stomach — elevated insulin blunts GH release
- Cycle: 3–6 months on, 1–2 months off
Ipamorelin + CJC-1295 with DAC:
- 1–2 mg CJC-1295 DAC once or twice weekly
- 200–300 mcg Ipamorelin daily or twice daily
- Simpler dosing schedule; less pulsatile GH profile
Expected Effects
Users report and research supports:
- Improved sleep quality and deeper sleep (GH is primarily released during slow-wave sleep)
- Reduced body fat, particularly visceral fat
- Increased lean muscle mass over months of use
- Faster recovery from exercise and injury
- Improved skin quality and collagen density
- IGF-1 elevation (measured in blood tests)
Safety Considerations
GH secretagogues are generally considered safe for healthy adults. Key considerations:
- Can cause transient water retention, especially in the first few weeks
- May cause tingling or numbness (carpal tunnel-like symptoms) at higher doses
- Contraindicated in active cancer (GH/IGF-1 are mitogenic)
- Long-term effects on endogenous GH axis suppression are not well characterised