Ipamorelin (Growth Hormone Secretagogue Receptor Agonist)
A selective growth hormone secretagogue that stimulates GH release from the pituitary via the ghrelin receptor (GHSR). Considered the 'cleanest' GH peptide due to minimal effects on cortisol, prolactin, and appetite.
Ipamorelin works like a key that fits only the growth hormone lock on your pituitary gland. Unlike similar peptides that also trigger cortisol, hunger hormones, and prolactin, Ipamorelin is precise -- it mostly just releases growth hormone. When combined with CJC-1295 (which works on a different lock), the two together release much more GH than either alone.
Clean GH elevation with minimal side effects makes it ideal for anti-aging protocols. Restores youthful GH patterns.
GH elevation supports protein synthesis. Combined with CJC-1295 for meaningful body composition improvement.
GH promotes lipolysis. Best results with exercise and proper diet.
Pre-bed dosing amplifies natural nocturnal GH pulse. Improved sleep quality commonly reported.
GH/IGF-1 promote collagen synthesis.
GH supports tissue repair systemically. Not as targeted as healing peptides.
Phase 2 trials showed prokinetic effects (improved gut motility). May benefit post-surgical gut recovery.
Indirect GH/IGF-1 neuroprotective effects.
Indirect hormonal support.
GH supports immune function indirectly.
Ipamorelin binds to the growth hormone secretagogue receptor (GHSR-1a), also known as the ghrelin receptor, on anterior pituitary somatotroph cells. This triggers GH release through a pathway distinct from GHRH signaling. Ipamorelin is highly selective for GH release and does not significantly affect ACTH (cortisol) or prolactin secretion at physiological doses. It acts synergistically with GHRH analogs because GHSR activation lowers the threshold for GHRH-induced GH release.
The gold standard GH peptide protocol. Inject on empty stomach (2+ hours fasted). Pre-bed dose amplifies nocturnal GH pulse. Some users do morning + pre-bed (2x) or morning + post-workout + pre-bed (3x).
Less common than the stack. Solo use produces moderate GH elevation. Stacking with CJC-1295 is strongly preferred for synergistic effect.
Less common than with other GH peptides due to selectivity
Ipamorelin is considered the cleanest GH secretagogue. Unlike GHRP-6, it does not significantly increase appetite, cortisol, or prolactin at standard doses. Side effect profile is milder than MK-677, GHRP-2, or GHRP-6.
GH/IGF-1 promote cell growth. Elevated IGF-1 associated with cancer risk.
GH can worsen insulin resistance. Less impact than MK-677 but still requires monitoring.
No safety data.
Stimulates pituitary function.
Primary outcome. Dose-dependent IGF-1 elevation.
Direct mechanism. Pulsatile GH release via GHSR.
KEY DIFFERENTIATOR: Ipamorelin does NOT significantly raise cortisol, unlike GHRP-6 and GHRP-2.
KEY DIFFERENTIATOR: Ipamorelin does NOT significantly raise prolactin, unlike GHRP-6 and GHRP-2.
Mild GH-mediated glucose elevation possible. Less impact than MK-677.
THE standard stack. GHSR agonist (Ipamorelin) + GHRH analog (CJC-1295) = synergistic GH release. Always recommended together.
No known interactions. Complementary -- GH for systemic recovery, BPC-157 for targeted healing.
No known interactions.
Both stimulate GH via GHSR (MK-677 is also a GHSR agonist). Redundant mechanism. MK-677 has more side effects. Usually one or the other.
Both are GHSR agonists. Redundant mechanism. GHRP-6 has significantly more side effects (hunger, cortisol, prolactin).
GH may worsen insulin resistance. Monitor if combining with metabolic peptides.
Raun K, Hansen BS, Johansen NL, et al. - Eur J Endocrinol (1998) - Preclinical + Phase 1
Ipamorelin is the first highly selective GH secretagogue. Does not release ACTH, cortisol, prolactin, FSH, LH, or TSH at doses that maximally stimulate GH release. Potent and selective in both animal models and initial human studies.
Limitations: Initial characterization study.
Greenwood-Van Meerveld B, et al. - Various (Phase 2 program) (2005) - Phase 2 clinical trial
Studied for accelerating recovery of GI function after surgery. Showed prokinetic effects. Development discontinued despite positive signals.
Limitations: Program discontinued. Full results not widely published.
Ipamorelin is the community's preferred GHSR agonist specifically because it doesn't cause the side effects of alternatives. GHRP-6 makes you ravenously hungry and spikes cortisol. MK-677 raises blood sugar and prolactin. Ipamorelin just releases GH cleanly. The CJC-1295/Ipamorelin combo is considered the 'starter' GH peptide stack -- low side effects, moderate GH elevation, good for body composition and recovery without the complexity of HGH. Community advice: always pair with CJC-1295 (no DAC), inject fasted, prioritize the pre-bed dose. Typical cycle cost: $60-120/month for both peptides from research vendors.
Research chemical. Not FDA-approved. Phase 2 trials conducted but development discontinued. Available from research chemical vendors and some peptide clinics.
Ipamorelin is not FDA-approved. Novo Nordisk conducted Phase 2 trials for postoperative ileus but discontinued development. It is available as a research chemical. Commonly prescribed by anti-aging and peptide therapy clinics alongside CJC-1295. Not specifically named on WADA prohibited list but GH secretagogues as a class are prohibited in tested sports.
Multiple human pharmacokinetic and clinical studies. Phase 2 trials for postoperative ileus. Good human safety and efficacy data for GH release. Not FDA-approved for any indication.
Disclaimer: This information is for educational and research purposes only. PepStack does not provide medical advice, diagnosis, or treatment recommendations. Consult a qualified healthcare provider before using any peptide or supplement. Research suggests these compounds may have various effects, but individual results vary and many claims require further clinical validation.