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Ipamorelin

Selective growth hormone releasing peptide with minimal side effects

Ipamorelin molecular structure

🛑 WADA BANNED - Prohibited in competitive sports as selective growth hormone releasing peptide

Overview

Ipamorelin is a growth hormone-releasing peptide (GHRP) that tells your pituitary gland to produce more growth hormone. It's considered one of the "cleanest" options in its class because it specifically targets growth hormone without significantly affecting other hormones. **Why choose Ipamorelin?** Unlike other growth hormone peptides that can spike cortisol (stress hormone) or increase appetite dramatically, Ipamorelin is highly selective. It gives you the growth hormone boost without as many unwanted side effects. **What the research shows:** • Stimulates natural, pulsatile growth hormone release • Minimal impact on cortisol, prolactin, or appetite • May support lean muscle development and fat loss • Could improve sleep quality and recovery • Often combined with CJC-1295 for enhanced effects **How it works:** Ipamorelin mimics ghrelin (the "hunger hormone") but is much more selective. It binds to growth hormone secretagogue receptors in your pituitary, triggering GH release in a pattern similar to your body's natural rhythms. **Typical use:** Injected subcutaneously, often 2-3 times daily or before bed to enhance natural nighttime GH pulses. **Important to know:** Ipamorelin is banned by WADA and not FDA-approved. While research is promising, large-scale human clinical trials are limited. --- **Sources:** Raun K, et al. (1998) European Journal of Endocrinology | Anderson LL, et al. (2009) Journal of Pharmacology and Experimental Therapeutics

Last reviewed: 2026-08-18

Identity & Aliases

Also known as

IpamorelinNN703ipamorelin acetategrowth hormone releasing peptide (GHRP) analog

Status: Research compound - Growth hormone agonist

CAS170851-70-4
PubChem9831659

Full composition (formula, molecular weight, sequence) in Quick Facts →

Research Areas

Growth hormone secretagogue researchAnabolic and metabolic researchGastrointestinal motility (investigational)Aging and sarcopenia (investigational)

Available Evidence

Human

A human pharmacokinetic/pharmacodynamic study in healthy volunteers demonstrated dose-dependent GH release after ipamorelin administration and characterized its pharmacokinetics. No large clinical trials support its use for muscle growth or fat loss.

Animal

Rodent and other animal studies show ipamorelin is a potent, selective GH secretagogue acting through the ghrelin/growth hormone secretagogue receptor (GHS-R1a), with less effect on ACTH and cortisol than earlier GHRPs.

In Vitro

Receptor-binding and functional assays confirm selective agonist activity at the growth hormone secretagogue receptor (GHS-R1a) with little activity at other tested receptors.

Uncertain

Bodybuilding use of ipamorelin - often combined with GHRH analogs such as CJC-1295 or sermorelin - for muscle gain and fat loss is based on the GH secretagogue mechanism and limited human PK data rather than clinical efficacy trials.

Key Studies & Findings

2 studies
Preclinical

Preclinical characterization identified ipamorelin (NN703) as a selective, potent GH secretagogue with an improved endocrine profile relative to earlier GHRPs.

Preclinical studies (Novo Nordisk development program)

Benefits & Effects

18 documented

Increases lean muscle mass

Reduces body fat

Improves sleep

Collagen production.

Muscle protein synthesis

anecdotal

Improved sleep quality

anecdotal

Collagen turnover support

anecdotal

Clean GH stimulation

anecdotal

Enhanced recovery

anecdotal

Body composition changes

anecdotal

GH Selectivity: First selective GHRP; no cortisol/ACTH release

clinical

Increases lean muscle mass

Reduces body fat

Improves sleep

Collagen production.

Selective GH release without hypothalamic-pituitary-adrenal axis activation

preclinicalhormonal

Reduced side effect profile compared to other GH secretagogues

preclinicalsafety

Comparable efficacy to GHRP-6 for GH release

preclinicalefficacy

Side Effects & Safety

9 reported

Does NOT stimulate ACTH or cortisol (unique selectivity profile)

mildnone

No ACTH/cortisol release

mild

Injection site reactions

mild

Overall AE incidence

mild

Mild dizziness

mildUncommon

Rare local irritation

severeRare

Headache

mildUncommon

Mild side effect

mild87.5% vs 94.8% placebo Reversible

Management: No specific management

Dose-dependent

Flushing

mildUncommon

Limitations & Open Questions

Published human data are essentially limited to single-dose PK/PD studies from the 1990s development program. No randomized trials demonstrate meaningful clinical benefit for muscle growth, body composition, or aging, and long-term safety of chronic secretagogue use is unknown. The peptide is not FDA approved.

Pharmacology

Ipamorelin is a synthetic pentapeptide GH secretagogue that acts as a selective agonist at the ghrelin/growth hormone secretagogue receptor (GHS-R1a). In human PK studies it was administered by injection and produced dose-dependent GH pulses with rapid onset. Half-life values derive mainly from PK modeling literature and vary with assay and route.

Reported Research Dosing

Reported values from research literature and community protocols. Educational reference only — not a dosing recommendation or medical advice.

100-300 mcg 1-3x/day

Route: SC
Half-life: ~2 hours

Research Protocols

General Health & Longevity

Dose
200mcg
Frequency
1x daily before bed
Route
SubQ

Body Composition

Dose
250-300mcg
Frequency
2x daily (morning, pre-workout)
Route
SubQ

Athletic Performance

Dose
200-250mcg
Frequency
2-3x daily (morning, pre/post workout)
Route
SubQ

Sleep & Recovery

Dose
200mcg
Frequency
1x daily 30min before bed
Route
SubQ

Anti-Aging Protocol

Dose
200-250mcg
Frequency
1-2x daily (morning, bedtime)
Route
SubQ

Research protocols are for educational purposes only. Always consult qualified medical professionals.

Frequently Asked Questions

Does ipamorelin build muscle?

It stimulates GH secretion in human PK studies, but no clinical trials demonstrate muscle growth; muscle-building claims rest on mechanism and anecdote.

Is ipamorelin FDA approved?

No. It is an investigational compound (originally NN703, Novo Nordisk) that was never approved for any indication.

What are the risks?

As a GH secretagogue, chronic use carries theoretical risks from sustained GH/IGF-1 elevation; long-term human safety data are lacking.

Research Citations

Related Resources

Quick Facts

Formula

C38H49N9O5

Molecular Weight

711.85

Sequence

Aib-His-D-2Nal-D-Phe-Lys-NH2

Mechanism

Selective GH secretagogue with minimal side effects

Safety Information

Research compound only. Forbidden in sport. May cause temporary flushing, mild head pressure, or minor water retention.

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