ipamoreline

What is ipamoreline

ipamoreline is a synthetic pentapeptide and belongs to the family of Growth Hormone Releasing Peptides (GHRPs). It was developed by Novo Nordisk in the 1990s as a selective ghrelin receptor agonist with the aim of increasing growth hormone release without producing the side effects of older GHRPs (GHRP-6, GHRP-2).

Amino acid sequence: Aib-His-D-2-Nal-D-Phe-Lys-NH2. Molecular weight: 711.86 g/mol. CAS No: 170851-70-4. The internal Novo-Nordisk code was NNC 26-0161.

Clinical trials ran until Phase 2 for the treatment of postoperative ileus. Novo Nordisk stopped development in 2007 because the primary endpoint was not reached. There is no authorisation for medicinal products.

Mechanism of action

ipamoreline selectively binds the ghrelin receptor (GHSR-1a) in the hypothalamus and pituitary gland and triggers a pulsatile release of growth hormone (GH). Unlike older GHRPs, it has virtually no effect on cortisol, prolactin and aldosterone. This is the key advantage and the reason why ipamoreline is so popular in the research use community.

The GH pulses from ipamoreline are shorter and higher than the natural pulses, but the overall pattern remains physiologically closer to the body’s secretion than with continuously administered recombinant growth hormone (rhGH).

In combination with a GHRH analogue such as CJC-1295, a synergistic effect is produced: GHRH stimulates the synthesis and storage of GH in the pituitary gland, ipamoreline stimulates the output. The combined GH response is significantly higher than the individual effects.

Areas of application in research

Age-related GH deficiency: Increase in the body's own GH release
Postoperative ileus: Original Novo-Nordisk indication
Sarcopenia: Maintaining muscle mass in older adults
Recovery after injuries and operations: GH-related repair effects
Bone density: Increase in osteogenic activity in animal models
Sleep architecture: Improvement of Deep Sleep Phases

Study situation

Compared to MK-677, the human database is thinner because clinical development was discontinued early.

Important works:

Raun et al. (European Journal of Endocrinology, 1998): One of the first characterizations established the selectivity for GH without cortisol/prolactin effects.
Beck et al. (European Journal of Endocrinology, 1998): GH response in healthy adults
Gobburu et al. (Journal of Clinical Pharmacology, 1999): Pharmacokinetics in humans
Postoperative ileus studies (phase 2): missed endpoints, therefore developmental stop

What is clear: ipamoreline increases GH and IGF-1 reproducibly, without cortisol increase. What remains unclear is whether these increases translate into clinically relevant outcomes (muscle mass, function, anti-aging markers). Data from controlled long-term studies are missing.

Mixing (reconstitution)

Typical Vial sizes: 2 mg, 5 mg, 10 mg lyophilisate.

5-mg Vial with 1 ml of bacteriostatic water → 5 mg/ml
5 mg Vial with 2 ml → 2.5 mg/ml (corresponds to 250 mcg per 0.1 ml)
5-mg Vial with 2.5 ml → 2 mg/ml for finer dosage

After mixing cooling 2 to 8 degrees, stability about 4 to 6 weeks. Lyophilisateeeee stable at -20 degrees over years. Clear, colourless solution.

Dosage range (research data)

From studies and research protocols:

Single dose: 100 to 300 mcg, subcutaneous
Frequency: 1 to 3 times daily
Timing: ideally on an empty stomach, at least 2 hours after the last meal (glucose and free fatty acids dampen the GH response)
Preferred times: morning sober, after training, before going to bed
Combination with CJC-1295 (Mod GRF 1-29) typical in research
Cycle duration: 8 to 16 weeks, then break

These values are research references.

Side effects

ipamoreline is considered particularly clean in its class. The most common effects:

Hunger increase (ghrelin effect, significantly weaker than MK-677 or GHRP-6)
Temporary fatigue or slight drowsiness after injection
Water retention (GH effect)
Local irritation at the injection site
Rare headaches
Prolonged use risk for insulin resistance (GH effect)
Carpal tunnel-like symptoms at high cumulative doses

Unlike GHRP-2 and GHRP-6, there is no relevant cortisol or prolactin increase. Theoretical tumor risks in active diseases due to IGF-1 increase.

Half-Life and Pharmacokinetics

Elimination half-life: approximately 2 hours. Hence the multiple daily dosage in research protocols.

Bioavailability subcutaneously: high, rapid absorption. Maximum GH pulse around 30 to 60 minutes after injection. Metabolism via peptide degradation processes, no relevant CYP interactions.

Oral bioavailability low, hence injection standard.

Frequent questions

Why ipamoreline and not directly rhGH? ipamoreline stimulates the body’s own pulsatile secretion, which is more physiological than continuous rhGH levels. In theory, fewer side effects. Clinically, however, rhGH is better documented in real GH deficiency.

What does the combination with CJC-1295 mean? GHRH (CJC-1295) stimulates GH production, ipamoreline stimulates output. Synergy leads to higher GH peaks than any substance alone.

When to take? On an empty stomach, at least 2 hours away from the last meal. Glucose and insulin dampen the GH response.

Does ipamoreline also work Orally? Practically hardly. Peptidic, hence GI degradation. For Oral effect, MK-677 would be the alternative.

How long cycle? Research protocols often go 8 to 16 weeks, then break. Longer continuous use has led to receptor desensitisation in animal studies.

Legal status U.S.

As of 2026: ipamoreline has no pharmaceutical license in Germany, Austria and Switzerland. Sales in the research-use-only rail. Therapeutic application involves the AMG.

WADA status: ipamoreline is on the prohibited list, category S2 (peptide hormones, growth factors). Clearly forbidden for athletes.

Own import: §73 AMG restrictions.

Related compounds

CJC-1295 (Mod GRF 1-29)GHRH analogue, standard combination
MK-677 (Ibutamors)Oral ghrelin mimetic
GHRP-2Older GHRP, higher cortisol effects
GHRP-6Older GHRP, strongest appetite effect
hexarelinePotent GHRP, with cortisol increase
tesamorelineGHRH analogue approved for HIV lipodystrophy

Note: All information is for research information only. These peptides are not approved as medicines in Germany. The contents do not replace medical advice. Application to humans is not legally covered in Germany.