Ipamorelin: what this GHRP peptide is
A five-amino-acid synthetic peptide that nudges the pituitary to release the body's own growth hormone — and, in animal studies, with less effect on other hormones than older GHRPs.
TL;DR
- Ipamorelin is a five-amino-acid synthetic peptide in the growth-hormone-releasing peptide (GHRP) family.
- It signals the pituitary gland to release the body's own growth hormone, working at the ghrelin receptor rather than the GHRH receptor.
- In published research, mostly in animals, ipamorelin is described as more selective than older GHRPs, with less effect on cortisol and prolactin.
What it is
Ipamorelin is a synthetic peptide built from five amino acids. It belongs to a family called growth-hormone-releasing peptides, or GHRPs (in plain English: small molecules that signal the pituitary to release growth hormone). Picture the pituitary as a thermostat. Ipamorelin is a key that opens one specific door on that thermostat (Raun et al., European Journal of Endocrinology, 1998).
The "selective" label matters. Older GHRPs sometimes also nudged cortisol and prolactin upward. Ipamorelin was designed to leave those alone, and in studies in rats and pigs it largely did.
How it works
The body has its own built-in signal that tells the pituitary, "release some growth hormone." That signal is a hormone called ghrelin. Ipamorelin imitates ghrelin at the ghrelin receptor — a lock on the surface of pituitary cells. When ipamorelin fits the lock, the cell releases a pulse of growth hormone (Sigalos and Pastuszak, Sexual Medicine Reviews, 2018).
In animal studies, working through this specific door meant a growth-hormone pulse without the broader hormonal effects of older GHRPs.
Who asks about it
People usually arrive at ipamorelin through one of two doors. Some are reading about longevity science and want to understand what "selective" means. Others have heard about the CJC-1295 plus ipamorelin combination and want to know what each piece does. The question is the same: how is this different from growth hormone itself, and why is it called "selective"?
What the research says
The published research on ipamorelin is mostly small studies and pharmacology work. Reviews describe a more selective growth-hormone release pattern compared with older GHRPs, with less effect on cortisol and prolactin (Sigalos and Pastuszak, Sexual Medicine Reviews, 2018). Ipamorelin has also been studied in postoperative recovery contexts. Long-term outcome trials in healthy aging adults are limited.
What to know
Side effects in published studies have been generally mild. Long-term outcome trials in healthy aging adults are limited, so long-term safety in that group has not been established.
The Halftime POV
Ipamorelin is interesting because it shows what a careful design can do. The first generation of GHRPs raised growth hormone, but they also raised other hormones. In animal studies, ipamorelin traded a little raw power for selectivity. That trade-off is worth understanding, and it is not evidence that ipamorelin improves health in people.
Related reading:
- Ipamorelin: the selective clean GH peptide
- CJC-1295 plus ipamorelin: why they are often discussed together
- Sermorelin explained
FAQ
Q: What is ipamorelin? A: Ipamorelin is a five-amino-acid synthetic peptide in the growth-hormone-releasing peptide family. It signals the pituitary gland to release the body's own growth hormone. It is one of the more selective GHRPs studied in the published literature.
Q: Is ipamorelin the same as sermorelin? A: No. Sermorelin and ipamorelin both push the body to release more of its own growth hormone, but they use different doors. Sermorelin works at the GHRH receptor. Ipamorelin works at the ghrelin receptor.
Q: What is ipamorelin's compounding status? A: FDA removed ipamorelin from Category 2 on September 27, 2024, after its nomination was withdrawn. As of September 14, 2026, ipamorelin is not in any FDA 503A category and is not on the 503A bulks list. At its October 29, 2024 meeting, FDA's Pharmacy Compounding Advisory Committee voted against adding ipamorelin to the 503A bulks list. This page does not cover obtaining ipamorelin.
Disclaimer
This article is educational and is not medical advice. Compounded medications are not FDA-approved.
Sources
- Raun K, et al. Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology, 1998.
- Sigalos JT, Pastuszak AW. The safety and efficacy of growth hormone secretagogues. Sexual Medicine Reviews, 2018.
This article discusses compounds whose FDA compounding status has been under review (see our FDA categorization explainer). This article is provided for educational purposes only and does not constitute medical advice or an offer to sell.
Frequently asked questions
What is ipamorelin?
Ipamorelin is a five-amino-acid synthetic peptide in the growth-hormone-releasing peptide family. It signals the pituitary gland to release the body's own growth hormone. It is one of the more selective GHRPs studied in the published literature.
Is ipamorelin the same as sermorelin?
No. Sermorelin and ipamorelin both push the body to release more of its own growth hormone, but they use different doors. Sermorelin works at the GHRH receptor. Ipamorelin works at the ghrelin receptor.
What is ipamorelin's compounding status?
FDA removed ipamorelin from Category 2 on September 27, 2024, after its nomination was withdrawn. As of September 14, 2026, ipamorelin is not in any FDA 503A category and is not on the 503A bulks list. At its October 29, 2024 meeting, FDA's Pharmacy Compounding Advisory Committee voted against adding ipamorelin to the 503A bulks list. This page does not cover obtaining ipamorelin.
