# Ipamorelin

> Evidence tier A — Controlled human trials · GH & Growth · reviewed 2026-11-08
> Source page: https://peptidemeta.com/p/ipamorelin/

Also known as: NNC 26-0161, Ipamorelin acetate

## Quick answers

**What is Ipamorelin?**

A selective growth hormone secretagogue that stimulates the pituitary gland with minimal impact on cortisol or prolactin.

**How strong is the evidence for Ipamorelin?**

Tier A (controlled human trials) on the peptidemeta evidence scale. Randomized, placebo-controlled phase 2 trials in postoperative ileus were completed (no benefit shown); not approved.

**Is Ipamorelin FDA-approved?**

No. Ipamorelin is not approved by the FDA for any use.

**Is Ipamorelin banned in sport?**

Yes. Ipamorelin is prohibited in sport by the World Anti-Doping Agency under S2 (peptide hormones, growth factors, related substances and mimetics).

**How does Ipamorelin work?**

Ipamorelin is a pentapeptide ghrelin receptor (GHS-R1a) agonist that stimulates growth hormone release from the anterior pituitary in a dose-dependent manner. Unlike other GHRPs, it has high selectivity for GH release without significantly elevating ACTH, cortisol, or prolactin, making it the cleanest GHRP available.

**What is known about the safety of Ipamorelin?**

Well-tolerated in Phase II clinical trials. Common side effects include transient headache, flushing, and mild water retention.

## Key facts

- **Evidence tier:** A (Controlled human trials)
- **FDA:** not approved
- **WADA:** prohibited (S2)
- **Peptide:** yes
- **Discovered:** 1998 — Described by Novo Nordisk as a selective GH secretagogue.
- **Routes studied:** Subcutaneous, Intramuscular

## Overview

A selective growth hormone secretagogue that stimulates the pituitary gland with minimal impact on cortisol or prolactin. Considered one of the mildest and most targeted GH-releasing peptides.

## Mechanism

Ipamorelin is a pentapeptide ghrelin receptor (GHS-R1a) agonist that stimulates growth hormone release from the anterior pituitary in a dose-dependent manner. Unlike other GHRPs, it has high selectivity for GH release without significantly elevating ACTH, cortisol, or prolactin, making it the cleanest GHRP available.

## Effects reported in research

_Reported outcomes, not promises; see the evidence tier._

- Increased growth hormone release
- Improved sleep quality
- Enhanced fat metabolism
- Strengthened bone mineral density

## Safety & unknowns

Well-tolerated in Phase II clinical trials. Common side effects include transient headache, flushing, and mild water retention. Does not significantly raise cortisol or prolactin. Not FDA-approved. Banned by WADA.

## Status sources

- [Beck et al. 2014, Int J Colorectal Dis (phase 2 RCT)](https://pubmed.ncbi.nlm.nih.gov/25331030/)
- [Raun et al. 1998, Eur J Endocrinol](https://pubmed.ncbi.nlm.nih.gov/9849822/)
- [WADA 2026 Prohibited List](https://www.wada-ama.org/en/prohibited-list)

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Educational reference only — not medical advice. No dosing information is published. Tiers rate the strength of published evidence, not effectiveness or safety.