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Medical notice — For research and educational purposes only. Not medical advice. Consult a licensed physician before using any peptide or compound.

Ipamorelin

growth-hormonegh-release
Regulatory status — Research use only — not approved for human use

Ipamorelin is a synthetic pentapeptide ghrelin receptor (GHSR1a) agonist and selective growth hormone secretagogue originally characterized for its highly selective GH-releasing properties with minimal off-target hormonal effects [1]. Human pharmacokinetic data from a controlled study demonstrate a short terminal half-life of approximately 2 hours and dose-proportional kinetics across a range of intravenous doses [2]. Outside of a phase II randomized controlled trial in postoperative ileus [3], human efficacy data are absent, and most mechanistic evidence derives from animal and in vitro models.

Evidence coverage

40/47 claims verified by independent fact-checker.

1 claim pending coverage
  • FDA prescribing-label data(1 claim)

Pepteligence regenerates entries quarterly and when new high-tier evidence appears.

Quick facts

Half-life
—
Typical dose
See research context
Route
multiple
Frequency
[insufficient evidence in research packet — no approved or consensus dosing frequency established in human clinical data]
Cycle length
—
Evidence strength
Phase III RCTs

Suggested labs for this peptide class — educational reference only; not medical advice.

TL;DR

  • Half-life: — — dosed —.
  • Administered via multiple.
  • Evidence base: randomised controlled trials.
  • Primary goals: growth-hormone, gh-release.
EVIDENCE HIERARCHYRCTsObservationalAnimal studiesAnecdotal

Randomised controlled trials

How we evaluate evidence →

How it works

GHRH analogues stimulate pulsatile GH release from the pituitary, elevating IGF-1 and promoting fat oxidation.

Ipamorelin is a pentapeptide agonist at the ghrelin receptor subtype GHSR1a, acting as a selective growth hormone secretagogue [1]. In vitro studies using rat pituitary cells demonstrated that ipamorelin stimulates GH release with an EC50 of 1.3 ± 0.4 nmol/L and an Emax of 85 ± 5%, indicating potent and near-maximal efficacy at the receptor [1]. Unlike earlier growth hormone secretagogues, ipamorelin was characterized as the first selective GHS, showing minimal stimulation of cortisol, prolactin, or ACTH release in preclinical models [1]. Mechanistic data indicate that ipamorelin's GH-releasing effects are mediated through the GHSR1a pathway [12], and animal studies indicate that chronic ipamorelin treatment alters somatotroph cell populations and GH content in rat pituitary tissue [13]. Animal studies further indicate that ipamorelin acts as a peripherally restricted ghrelin receptor agonist capable of attenuating visceral and somatic pain in experimental models of non-inflammatory hypersensitivity and mechanical allodynia [8]. Animal studies also suggest GH-independent effects on adiposity: ipamorelin increased fat pad weights relative to body weight in both GH-deficient and GH-intact mouse models, pointing to direct adipogenic signaling independent of the GH axis [7]. In streptozotocin-diabetic mice, intravenous ipamorelin induced GH hypersecretion (GH levels 150 ± 35 µg/L versus 62 µg/L in controls) alongside reduced hepatic IGF-I mRNA expression, suggesting altered downstream signaling in a diabetic metabolic context [11]. Animal studies indicate that ipamorelin inhibited cisplatin-induced weight loss in ferrets at doses of 1–3 mg/kg administered intraperitoneally, an effect shared with the related ghrelin mimetic anamorelin, which additionally demonstrated anti-emetic properties via a central mechanism [9]. These mechanistic findings are derived entirely from in vitro and animal models; their relevance to human physiology has not been established in controlled clinical trials.

What the research says

Research summary content coming soon. Check the references section for indexed studies.

100%50%25%0%00h1t½2h2t½4h3t½6h4t½8h
Approximate plasma concentration over 4 half-lives (2h × 4 = 8h)

Protocol lifecycle

BeforeDuringAfter

Before — Pre-cycle readiness

Readiness checklist

Regulatory and legal
  • Confirm ipamorelin is not banned in your sport or jurisdiction — it is currently on the WADA Prohibited List [4].
  • Understand that ipamorelin has no approved therapeutic indication; any use outside clinical trials is off-label and investigational [3].
Medical evaluation
  • Obtain baseline endocrine panel including IGF-1 and fasting glucose given animal data showing GH hypersecretion and altered IGF-I mRNA in diabetic models [11].
  • Discuss with a licensed clinician; no published human dosing or safety guidance exists beyond a small pharmacokinetic study (n=8 per dose level) [2].
Evidence awareness
  • Acknowledge that all efficacy claims for muscle growth, fat loss, recovery, or pain management in humans lack clinical trial evidence — these are extrapolated from animal and in vitro studies only [8], [9].
  • Understand that modified ipamorelin analogs exist in unregulated markets with unknown safety profiles [6].
  • Confirm ipamorelin is not prohibited in your jurisdiction or sport; it is on the WADA Prohibited List [4].
  • Assess baseline metabolic and endocrine status — animal data suggest potential GH-independent adipogenic effects that may be relevant in certain metabolic phenotypes [7].
  • Note that no human data establish a safe starting dose outside the investigational pharmacokinetic study context [2].

During — Active protocol

Protocol notice — The following describes common protocols reported in research and community sources. This is not medical advice. Dosing, frequency, and duration should be determined with a licensed physician familiar with peptide research.
  • Human pharmacokinetic data confirm dose-proportional kinetics across intravenous doses from 4.21 to 140.45 nmol/kg over 15 minutes in a controlled research setting [2]; extrapolation to subcutaneous or intranasal community use is not supported by published evidence.
  • The only published human efficacy trial evaluated ipamorelin for postoperative ileus in bowel resection patients; outcomes from this phase II RCT are the sole clinical human efficacy data available [3].
  • Monitor for any signs consistent with GH-axis perturbation; no human safety monitoring guidance exists beyond the single pharmacokinetic study [2].

After — Post-cycle

  • [insufficient evidence in research packet — no human data on cycling, washout, or post-cycle management for ipamorelin]

Stacks it appears in

Ipamorelin is typically used as a standalone compound. Stack data coming soon.

Related peptides

Other compounds indexed on Pepteligence that share research tags with Ipamorelin. Educational context only.

CJC-1295

Tier 3
gh-release

Tesamorelin

Tier 1
growth-hormone

Hexarelin

Tier 3
gh-release

MK-677

Tier 2
gh-release

Safety

Common side effects

  • ·[insufficient evidence in research packet — no systematic adverse event frequency data from human trials]

Rare side effects

  • ·[insufficient evidence in research packet]
Safety notice — Serious / theoretical risks:
  • Animal studies indicate GH-independent adipogenic signaling that could theoretically alter cardiometabolic risk parameters; not studied in humans [7].
  • GH hypersecretion observed in a diabetic animal model suggests potential for dysregulated GH axis activity in metabolically compromised individuals [11].

Contraindications

  • ·Competitive athletes subject to WADA or equivalent anti-doping authority testing — ipamorelin is prohibited in sport [4].
  • ·Conditions associated with altered GH/IGF-I axis sensitivity (e.g., diabetes mellitus) based on animal model data showing GH hypersecretion and reduced hepatic IGF-I mRNA; clinical relevance in humans not established [11].
  • ·Pregnancy, lactation, and pediatric populations — no safety data available in the research packet.

Community experiences

Community content — User-submitted experiences are self-reported and have not been verified. They do not constitute medical advice. Pepteligence aggregates community data under Section 230 protections.

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Ipamorelin — at a glance

PropertyIpamorelin—
Half-life——
Routemultiple—
Typical doseSee research context—
MechanismIpamorelin is a pentapeptide agonist at the ghrelin receptor subtype GHSR1a, acting as a selective growth hormone secretagogue. In vitro studies using rat pituitary cells demonstrated that ipamorelin stimulates GH release with an EC50 of 1.3 ± 0.4 nmol/L and an Emax of 85 ± 5%, indicating potent and near-maximal efficacy at the receptor. Unlike earlier growth hormone secretagogues, ipamorelin was characterized as the first selective GHS, showing minimal stimulation of cortisol, prolactin, or ACTH release in preclinical models. Mechanistic data indicate that ipamorelin's GH-releasing effects are mediated through the GHSR1a pathway, and animal studies indicate that chronic ipamorelin treatment alters somatotroph cell populations and GH content in rat pituitary tissue. Animal studies further indicate that ipamorelin acts as a peripherally restricted ghrelin receptor agonist capable of attenuating visceral and somatic pain in experimental models of non-inflammatory hypersensitivity and mechanical allodynia. Animal studies also suggest GH-independent effects on adiposity: ipamorelin increased fat pad weights relative to body weight in both GH-deficient and GH-intact mouse models, pointing to direct adipogenic signaling independent of the GH axis. In streptozotocin-diabetic mice, intravenous ipamorelin induced GH hypersecretion (GH levels 150 ± 35 µg/L versus 62 µg/L in controls) alongside reduced hepatic IGF-I mRNA expression, suggesting altered downstream signaling in a diabetic metabolic context. Animal studies indicate that ipamorelin inhibited cisplatin-induced weight loss in ferrets at doses of 1–3 mg/kg administered intraperitoneally, an effect shared with the related ghrelin mimetic anamorelin, which additionally demonstrated anti-emetic properties via a central mechanism. These mechanistic findings are derived entirely from in vitro and animal models; their relevance to human physiology has not been established in controlled clinical trials.—
Evidence strengthrctanecdotal
Primary goalgrowth-hormone—

Frequently asked questions

What is ipamorelin?
Ipamorelin is a synthetic pentapeptide that acts as a selective agonist at the ghrelin receptor (GHSR1a), classifying it as a growth hormone secretagogue (GHS). It was originally characterized for its highly selective GH-releasing properties with minimal off-target hormonal effects. It is not FDA-approved.
How does ipamorelin work?
Ipamorelin binds the GHSR1a receptor and stimulates pulsatile release of growth hormone from the pituitary gland. In vitro studies using rat pituitary cells demonstrated an EC50 of 1.3 ± 0.4 nmol/L and an Emax of 85 ± 5%, indicating potent and near-maximal receptor efficacy. Its selectivity at GHSR1a distinguishes it from earlier, less selective growth hormone secretagogues.
What is ipamorelin used for?
Human pharmacokinetic and pharmacodynamic data are available for ipamorelin. A proof-of-concept study investigated it for management of postoperative ileus in bowel resection patients. It is not approved for any clinical indication and is used only in research contexts.
Is ipamorelin FDA-approved?
No. Ipamorelin is not FDA-approved for any indication. It is classified as a research compound. Regulatory status varies by country — consult applicable regulations in your jurisdiction.
What are common dosages of ipamorelin?
No approved or consensus dosing for ipamorelin has been established in human clinical data. Human pharmacokinetic studies have characterized its absorption and elimination profile, but a clinically validated dosing regimen has not been established.
How is ipamorelin administered?
Ipamorelin has been studied via multiple routes in research settings. No administration route has been validated for efficacy or safety in controlled human trials.
What are common side effects of ipamorelin?
Because controlled human clinical trial data are limited, a comprehensive side-effect profile for ipamorelin has not been established. The available research does not document a specific common adverse-event pattern in humans.
Is ipamorelin prohibited in competitive sports?
Yes. Ipamorelin is prohibited in sport by the World Anti-Doping Agency (WADA) and equivalent anti-doping authorities. Athletes subject to anti-doping testing should not use ipamorelin.
Are there concerns about ipamorelin and diabetes or metabolic conditions?
Animal model data show GH hypersecretion and reduced hepatic IGF-1 mRNA with ipamorelin, raising a theoretical concern for conditions associated with altered GH/IGF-1 axis sensitivity such as diabetes mellitus. The clinical relevance in humans has not been established. People with metabolic conditions should consult a physician before considering any growth hormone secretagogue.
Can ipamorelin be combined with other peptides?
No combination protocols have been established in controlled research for ipamorelin. The existing source literature does not document evidence-supported combination uses for this compound.
Is ipamorelin legal?
Ipamorelin is not a scheduled controlled substance in the United States but is not FDA-approved for human use. Its legal status for possession and importation varies by country. This is not legal advice — consult applicable regulations in your jurisdiction.
How does ipamorelin differ from MK-677?
Both ipamorelin and MK-677 are growth hormone secretagogues that act at the ghrelin receptor, but they differ significantly in structure and route: ipamorelin is a peptide administered parenterally, while MK-677 is a non-peptide compound that is orally active. MK-677 has RCT data spanning up to approximately 2 years; ipamorelin's human clinical data are more limited.

References

  1. [1]

    Ipamorelin, the first selective growth hormone secretagogue.

    Raun K, Hansen B S, Johansen N L et al.

    European Journal of Endocrinology · 1998 · PMID 9849822

    View on PubMed →
  2. [2]

    Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers.

    Gobburu J V, Agersø H, Jusko W J et al.

    Pharmaceutical Research · 1999 · PMID 10496658

    View on PubMed →
  3. [3]

    Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients.

    Beck David E, Sweeney W Brian, McCarter Martin D et al.

    International Journal of Colorectal Disease · 2014 · PMID 25331030

    View on PubMed →
  4. [4]

    A new era of doping? Use of peptide and peptide-analog drugs in recreational and professional sport and bodybuilding: a critical review.

    Coutinho Luis F D, DE Oliveira Neves Lucas F, Camilo Rafael P

    The Journal of Sports Medicine and Physical Fitness · 2026 · PMID 41880199

    View on PubMed →
  5. [5]

    Determination of growth hormone releasing peptides metabolites in human urine after nasal administration of GHRP-1, GHRP-2, GHRP-6, Hexarelin, and Ipamorelin.

    Semenistaya Ekaterina, Zvereva Irina, Thomas Andreas et al.

    Drug Testing and Analysis · 2015 · PMID 25869809

    View on PubMed →
  6. [6]

    Glycine-modified growth hormone secretagogues identified in seized doping material.

    Gajda Paulina Marta, Holm Niels Bjerre, Hoej Lars Jakobsen et al.

    Drug Testing and Analysis · 2019 · PMID 30136411

    View on PubMed →
  7. [7]

    Growth hormone (GH)-independent stimulation of adiposity by GH secretagogues.

    Lall S, Tung L Y, Ohlsson C et al.

    Biochemical and Biophysical Research Communications · 2001 · PMID 11162489

    View on PubMed →
  8. [8]

    Attenuation of Visceral and Somatic Nociception by Ghrelin Mimetics.

    N Mohammadi Ehsan, Louwies Tijs, Pietra Claudio et al.

    Journal of Experimental Pharmacology · 2020 · PMID 32801950

    View on PubMed →
  9. [9]

    The growth hormone secretagogue receptor 1a agonists, anamorelin and ipamorelin, inhibit cisplatin-induced weight loss in ferrets: Anamorelin also exhibits anti-emetic effects via a central mechanism.

    Lu Zengbing, Ngan Man P, Liu Julia Y H et al.

    Physiology & Behavior · 2024 · PMID 39043357

    View on PubMed →
  10. [10]

    Analysis of new growth promoting black market products.

    Krug Oliver, Thomas Andreas, Malerød-Fjeld Helle et al.

    Growth Hormone & IGF Research · 2018 · PMID 29864719

    View on PubMed →
  11. [11]

    Growth hormone (GH) hypersecretion and GH receptor resistance in streptozotocin diabetic mice in response to a GH secretagogue.

    Johansen Peter B, Segev Yael, Landau Daniel et al.

    Experimental Diabesity Research · 2003 · PMID 14630569

    View on PubMed →
  12. [12]

    Pharmacological characterisation of a new oral GH secretagogue, NN703.

    Hansen B S, Raun K, Nielsen K K et al.

    European Journal of Endocrinology · 1999 · PMID 10427162

    View on PubMed →
  13. [13]

    Influence of chronic treatment with the growth hormone secretagogue Ipamorelin, in young female rats: somatotroph response in vitro.

    Jiménez-Reina L, Cañete R, de la Torre M J et al.

    Histology and Histopathology · 2002 · PMID 12168778

    View on PubMed →
  14. [?]

    The influence of ghrelin agonist ipamorelin acetate on the hypothalamic-pituitary-testicular axis in a cichlid fish, Oreochromis mossambicus.

    Gouda Mallikarjun, Ganesh C B

    Animal Reproduction Science · 2024 · PMID 38996787

    View on PubMed →

Compare Ipamorelin with…

CJC-1295 vs Hexarelin vs Ipamorelin

CJC-1295 · Hexarelin · Ipamorelin

View comparison →