Compound Reviews
Ipamorelin: A Selective Growth Hormone Secretagogue
Ipamorelin is studied because of what it does not do — a ghrelin receptor agonist with a notably narrow reported off-target profile.
July 28, 2026 · 5 min read · Novanta Research
Mechanism
Ipamorelin is a pentapeptide agonist at the growth hormone secretagogue receptor, the same receptor targeted by ghrelin. Activation of that receptor on pituitary somatotrophs stimulates growth hormone release.
Because it works through a receptor on the pituitary, the release it produces follows the body's own pulsatile pattern rather than replacing it — a distinction frequently made in the literature between secretagogues and exogenous growth hormone.
Why selectivity is the headline
Earlier secretagogues in the same class were reported to raise cortisol and prolactin alongside growth hormone. The published characterisation of ipamorelin emphasises much weaker effects on those axes at comparable growth hormone release.
That selectivity is the reason it remains a common comparator compound in secretagogue studies.
Comparisons within the class
CJC-1295 works upstream at the growth hormone-releasing hormone receptor rather than the ghrelin receptor, which is why the two are frequently studied together in the literature as complementary rather than redundant mechanisms.
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