The Peptide Atlas
Ipamorelin
A small five-amino-acid peptide that mimics ghrelin, one of the signals that triggers growth hormone release.
Class
Growth-hormone secretagogue (ghrelin mimetic)
Evidence
Human-tested
Status
Studied in research settings.
Forms
Subcutaneous injection
What people use it for
Recovery, sleep, and body composition, almost always as half of a stack with a GHRH peptide.
The signal
Your pituitary releases growth hormone when it gets told to, and there are two main ways the body says it: growth-hormone-releasing hormone, and ghrelin. Ipamorelin copies the ghrelin route.
How it works
It binds the ghrelin receptor on the pituitary, prompting a pulse of your own growth hormone. What made it notable when it was characterized in 1998 is selectivity: earlier peptides in this class also raised cortisol and prolactin, two hormones you don't want elevated, and ipamorelin doesn't [1].
What the research shows
Human studies exist but are few. A pharmacokinetic study mapped how it behaves in people [2], and a randomized proof-of-concept trial tested it in patients recovering from bowel surgery [3]. The development program ended without a larger push, so most of what's known about long-term use comes from clinical experience rather than trials.
What people get wrong
That it's interchangeable with sermorelin. They reach the same gland through different doors: sermorelin copies the releasing hormone, ipamorelin copies ghrelin. Stacks that combine a GHRH analog with a ghrelin mimetic exist precisely because the two routes are different.
References
- Raun K et al., Eur J Endocrinol (1998). Ipamorelin, the first selective growth hormone secretagogue. PubMed
- Gobburu JV et al., Pharm Res (1999). Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. PubMed
- Beck DE et al., Int J Colorectal Dis (2014). Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus. PubMed
Last reviewed 2026-08-24. Every reference is verified against the primary literature at review time. How the Atlas grades evidence