RESEARCH PROFILE
IPAMORELIN
Selective Growth Hormone Secretagogue • Ghrelin Receptor Agonist
Ipamorelin is a synthetic pentapeptide growth hormone secretagogue studied for its ability to stimulate endogenous growth hormone release through the ghrelin receptor while showing greater hormonal selectivity than several earlier growth hormone releasing peptides.
INVESTIGATIONAL • NOT FDA APPROVED • HUMAN PHARMACOLOGY DATA AVAILABLE
IPAMORELIN AT A GLANCE
Category
Growth hormone secretagogue
Compound Type
Synthetic pentapeptide
Primary Target
Ghrelin receptor • GHSR1a
Primary Research Pathway
Growth hormone • IGF-1 axis
Research Characteristic
Selective, pulsatile GH release
Regulatory Status
Not FDA approved
IMPORTANT DISTINCTION
Ipamorelin is not growth hormone and is not a GHRH analog.
Instead, it stimulates the body's own growth hormone release primarily through the growth hormone secretagogue receptor, GHSR1a, commonly called the ghrelin receptor.
This distinguishes it mechanistically from compounds such as CJC-1295 No DAC, Sermorelin, and Tesamorelin, which act through the GHRH receptor.
WHAT IS IPAMORELIN?
Ipamorelin is a synthetic five amino acid peptide developed as a selective growth hormone secretagogue.
It is sometimes identified in the research literature as NNC 26-0161.
Ipamorelin belongs to the broader family of growth hormone releasing peptides, but its pharmacological profile differs from earlier compounds such as GHRP-2 and GHRP-6.
Its defining research characteristic is its relative selectivity for growth hormone release.
Early pharmacological studies reported stimulation of GH without the same increases in cortisol, ACTH, or prolactin observed with some earlier growth hormone secretagogues.
Rather than supplying growth hormone directly, Ipamorelin activates signaling that encourages the pituitary to release endogenous GH.
Its research history includes animal pharmacology, human pharmacokinetic and pharmacodynamic studies, and clinical investigation for postoperative gastrointestinal recovery.
MECHANISM OF ACTION
Ipamorelin acts primarily through the body's ghrelin receptor signaling system.
GHRELIN RECEPTOR • GHSR1a
Ipamorelin binds to and activates the growth hormone secretagogue receptor type 1a, or GHSR1a.
This receptor is expressed in areas including the pituitary and hypothalamus and participates in regulation of endogenous growth hormone secretion.
PULSATILE GH RELEASE
GHSR1a activation stimulates the pituitary to release stored growth hormone.
Human pharmacodynamic research cited in the Project profile found that the GH response after Ipamorelin administration was relatively rapid, with peak GH occurring at approximately 40 minutes in one study.
The Project profile describes Ipamorelin's terminal half-life as approximately 1.6 to 2.5 hours based on published human pharmacokinetic modeling.
SOMATOSTATIN & GH REGULATION
Growth hormone secretion is regulated partly through the balance between stimulatory and inhibitory signaling.
Somatostatin functions as an important physiological inhibitor of GH secretion.
Ipamorelin appears to interact with this regulatory system in a manner that permits a temporary endogenous GH pulse rather than continuously supplying exogenous growth hormone.
DOWNSTREAM IGF-1
Growth hormone subsequently stimulates downstream pathways including production of insulin-like growth factor 1, or IGF-1.
Many longer-term physiological effects associated with the GH axis are mediated partly through IGF-1 rather than the brief GH pulse itself.
HORMONAL SELECTIVITY
One of Ipamorelin's most notable pharmacological characteristics is its relative selectivity.
Research by Raun and colleagues found that Ipamorelin stimulated GH release without significant increases in:
ACTH
Cortisol
and without the same prolactin effects associated with some earlier growth hormone secretagogues.
That selectivity distinguishes Ipamorelin pharmacologically, but it does not establish clinical benefits or long-term safety.
WHAT THE RESEARCH SHOWS
EARLY PHARMACOLOGY
Ipamorelin was characterized in preclinical research as a selective growth hormone secretagogue.
Research by Raun and colleagues demonstrated GH-releasing activity while showing substantially less stimulation of ACTH and cortisol than older GHRP compounds.
This work established much of the pharmacological rationale for subsequent human investigation.
HUMAN PHARMACOKINETIC & PHARMACODYNAMIC RESEARCH
Gobburú and colleagues studied Ipamorelin in approximately 40 healthy male volunteers.
The research demonstrated:
Dose-related pharmacokinetics
A relatively short terminal half-life
Rapid growth hormone stimulation
Peak GH response around 40 minutes after administration
This provides direct human evidence that Ipamorelin is biologically active as a GH secretagogue.
It does not, however, establish improvements in body composition, muscle growth, fat loss, sleep, recovery, or longevity.
PHASE II CLINICAL RESEARCH
Ipamorelin advanced into clinical development for postoperative ileus, a temporary impairment of gastrointestinal motility that can occur after surgery.
A randomized controlled Phase II study evaluated Ipamorelin in approximately 117 bowel-surgery patients.
The compound was administered intravenously during the postoperative period.
The trial reported that Ipamorelin was generally tolerated, but did not demonstrate the intended clinical efficacy signal for postoperative ileus.
The clinical development program was subsequently discontinued.
WHAT HUMAN RESEARCH ESTABLISHES
Published research supports that Ipamorelin:
Activates the ghrelin receptor pathway
Stimulates endogenous growth hormone release
Has measurable human pharmacokinetics and pharmacodynamics
Shows greater hormonal selectivity than some older GHRPs
WHAT HUMAN RESEARCH DOES NOT ESTABLISH
There are no controlled human clinical trials establishing Ipamorelin as an effective treatment for:
Muscle growth
Fat loss
Body recomposition
Exercise recovery
Sleep enhancement
Anti-aging
Longevity
Athletic performance
There is also no FDA approved subcutaneous Ipamorelin dosing regimen for these purposes.
IMPORTANT EVIDENCE LIMITATION
The commonly discussed subcutaneous protocols found throughout the peptide community are community-derived research practices rather than clinically validated dosing regimens.
SAFETY & RESEARCH CONSIDERATIONS
Ipamorelin has some human clinical exposure, but its complete safety profile for commonly marketed research uses has not been established.
REPORTED EFFECTS
Your Project profile identifies commonly reported effects including:
Mild headache
Light water retention or bloating
Mild appetite increase
Tingling in the hands or feet
Injection site irritation
At higher exposures or with longer GH-axis stimulation, additional concerns may include:
Joint stiffness
Temporary fatigue
Carpal tunnel type symptoms
These observations do not constitute a complete clinically validated adverse-event profile for long-term subcutaneous use.
CLINICAL TOLERABILITY
In the Phase II postoperative ileus study, intravenous Ipamorelin was administered to bowel-surgery patients during the postoperative period.
The trial did not identify a major difference in serious adverse events between treatment groups, although it also did not demonstrate the intended clinical efficacy.
Importantly, short-term intravenous tolerability in a clinical trial should not be treated as proof of long-term subcutaneous safety.
GLUCOSE & INSULIN SENSITIVITY
Growth hormone can influence insulin sensitivity and glucose metabolism.
Your Project profile therefore identifies glucose regulation as an important consideration, particularly in people with:
Diabetes
Prediabetes
Insulin resistance
Elevated fasting glucose
FLUID RETENTION
GH-axis stimulation can contribute to water retention.
Persistent swelling, neurological symptoms, shortness of breath, or substantial edema should not automatically be attributed to Ipamorelin and warrant appropriate medical evaluation.
GH, IGF-1 & CELL GROWTH
Growth hormone and IGF-1 participate in normal cellular growth and proliferation.
Your Project source therefore identifies active or recent cancer as an important precaution for GH-stimulating compounds.
This is a pathway-based safety consideration and does not establish that Ipamorelin causes cancer.
LIMITED POPULATION DATA
Safety has not been adequately established for commonly marketed Ipamorelin use in:
Pregnancy or breastfeeding
Children or adolescents
People with severe cardiovascular disease
People with uncontrolled diabetes
People with active or recent malignancy
Long-term safety data for repeated research use remain limited.
REGULATORY CONTEXT
IPAMORELIN IS NOT FDA APPROVED
Ipamorelin is not an FDA approved drug for human clinical use.
There is no FDA approved therapeutic indication or FDA approved subcutaneous dosing regimen for Ipamorelin.
CLINICAL DEVELOPMENT DOES NOT EQUAL APPROVAL
Ipamorelin reached human clinical development, including Phase II investigation for postoperative ileus.
That program did not establish sufficient efficacy for the studied indication and was discontinued.
Past clinical investigation should therefore not be represented as FDA approval or proof of effectiveness for unrelated uses.
COMPOUNDING STATUS
Your Project profile documents a changing FDA compounding history for Ipamorelin.
It notes that Ipamorelin was previously placed in Category 2 during FDA's interim 503A review process.
After subsequent review, FDA's Pharmacy Compounding Advisory Committee recommended against inclusion on the 503A Bulks List.
Your Project profile therefore states that Ipamorelin is not currently eligible for 503A pharmacy compounding under the status reflected in that source.
Because federal compounding policy can change, this regulatory point should be rechecked against current FDA information whenever the website is materially updated.
ANTI-DOPING STATUS
Ipamorelin and other growth hormone secretagogues are prohibited under World Anti-Doping Agency rules.
Athletes subject to drug testing should not assume that research status makes the compound permissible.
INTERNATIONAL STATUS
Your Project profile does not identify Ipamorelin as an approved medicine in the United States, European Union, United Kingdom, Canada, or Australia.
Research availability should not be interpreted as regulatory approval, clinical validation, or medical suitability.
ANALYTICAL DOCUMENTATION
Croix maintains available third party analytical documentation for specific samples and lots represented in its research library.
LOT SPECIFIC ANALYTICAL DOCUMENTATION
Analytical documentation is displayed only when Croix has a corresponding laboratory report that can be matched to the specific product and lot.
No matching standalone Ipamorelin COA is currently displayed.
IMPORTANT COA LIMITATION
When analytical documentation becomes available, results should apply only to the specific sample identified in the corresponding laboratory report.
A Certificate of Analysis for one sample does not establish the composition, purity, sterility, safety, efficacy, or characteristics of another sample, lot, batch, or product.
Croix requires the product, strength, lot or batch, sample ID, laboratory, and report date to be matched before analytical documentation is represented as supporting a product. Croix_Peptides_Brand_Pricing_Op…
A passing COA does not establish FDA approval, clinical efficacy, medical suitability, or the characteristics of unrelated lots.
SELECTED RESEARCH & REFERENCES
Raun K, Hansen BS, Johansen NL, et al.
Ipamorelin, the first selective growth hormone secretagogue.
European Journal of Endocrinology. 1998.
Foundational pharmacological research characterizing Ipamorelin as a selective growth hormone secretagogue.
Gobburú JV, Agersø H, Jusko WJ, Ynddal L.
Pharmacokinetic-pharmacodynamic modelling of ipamorelin, a growth hormone releasing peptide, in human volunteers.
Pharmaceutical Research. 1999.
Human pharmacokinetic and pharmacodynamic research characterizing Ipamorelin exposure and growth hormone response.
Bleeck D, Sweeney WB, McCarter MD; Ipamorelin 201 Study Group.
Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients.
International Journal of Colorectal Disease. 2014.
Controlled clinical research evaluating Ipamorelin for postoperative gastrointestinal recovery.
Ishida J, Saitoh M, Ebner N, et al.
Growth hormone secretagogues: history, mechanism of action, and clinical development.
JCMS Rapid Communications. 2020.
Review of growth hormone secretagogue pharmacology and clinical development.
ClinicalTrials.gov — NCT00672074
Ipamorelin in postoperative ileus.
Human clinical development record.
ClinicalTrials.gov — NCT01280344
Safety and efficacy research involving Ipamorelin and recovery of gastrointestinal function.
U.S. Food & Drug Administration
FDA materials concerning Ipamorelin acetate and Pharmacy Compounding Advisory Committee review.
World Anti-Doping Agency
Prohibited List — Peptide Hormones, Growth Factors, Related Substances and Mimetics.
EVIDENCE NOTE
The published human evidence demonstrates that Ipamorelin is a biologically active growth hormone secretagogue and provides human pharmacokinetic and short-term clinical exposure data.
It does not establish the commonly marketed body-composition, recovery, sleep, anti-aging, or performance benefits associated with Ipamorelin.
RESEARCH & EDUCATIONAL INFORMATION
This profile is provided for research and educational reference. It does not constitute individualized medical advice or establish Ipamorelin as safe or effective for personal use.
Ipamorelin is not FDA approved for human clinical use.
Published human research demonstrates growth hormone secretagogue activity and provides pharmacokinetic and pharmacodynamic information, but clinical trials have not established Ipamorelin as an effective treatment for muscle growth, fat loss, body recomposition, recovery, sleep enhancement, anti-aging, longevity, or athletic performance.
Community-derived subcutaneous schedules should not be interpreted as FDA approved or clinically validated dosing regimens.
Analytical documentation presented by Croix applies only to the specific samples and lots identified in corresponding laboratory reports.