Ipamorelin

Overview

Ipamorelin is a small synthetic peptide, a pentapeptide of five amino acids, classed as a growth hormone secretagogue. A secretagogue is a compound studied for prompting a gland to release its own hormone, so rather than supplying growth hormone from outside, Ipamorelin is studied for encouraging the body’s pituitary gland to release more of its own. Its defining feature in research is selectivity, the idea that it can do this cleanly without stirring up other hormones. It is most often studied as part of a pair with a growth hormone releasing hormone analog, which works through a complementary route. It sits in the growth hormone axis category and is one half of The Pulse blend.

How it works

Ipamorelin acts on the ghrelin receptor, also written as GHS-R1a, which sits in the pituitary gland and the hypothalamus and is part of the system that normally responds to ghrelin, the body’s hunger and growth signal. By activating that receptor, research describes Ipamorelin triggering a pulse of growth hormone from the pituitary. What sets it apart in the literature is that it does this while largely leaving other pituitary hormones, such as cortisol and prolactin, untouched, where some older compounds in its class also raised those. This selectivity is the property researchers most often highlight, because it allows the growth hormone pathway to be studied more cleanly. The body naturally releases growth hormone in pulses, and Ipamorelin is studied for working with that natural rhythm rather than overriding it.

What researchers study

Studies examine Ipamorelin for the size, timing, and selectivity of the growth hormone pulse it produces, and it is frequently paired in research with a growth hormone releasing hormone analog so the two complementary pathways can be studied together. The foundational work describing it as the first selective compound of its kind dates to the late 1990s, and it has been a reference point in growth hormone research ever since. Researchers are interested in the contrast between prompting the body’s own pulsatile release and supplying growth hormone directly, since the former preserves the natural feedback that keeps the system in balance. As with the rest of this category, the framing in research is on the body’s own signaling rather than on outcomes. It remains a standard tool for studying the growth hormone axis.

Published references

• Raun K et al. Ipamorelin, the First Selective Growth Hormone Secretagogue. European Journal of Endocrinology, 1998.
• Bowers CY. History of the Development of GH-Releasing Peptides and Analogues. Growth Hormone & IGF Research, 2012.

Research Use Only. Not for human or animal use.