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Growth-Factor Research · Secretagogue Class

Ipamorelin: Research Overview

What is ipamorelin? Ipamorelin is a synthetic pentapeptide — a chain of five amino acids — that acts as a selective agonist of the ghrelin receptor (GHS-R1a). It is studied in growth-hormone-secretagogue receptor pharmacology, where preclinical work has focused on its receptor selectivity. It is sold strictly for laboratory research use.
VP Peptides Ipamorelin research vial with box
Actual VP Peptides product · Research use only
Mechanistic · limited human data ≥99% HPLC purity COA with every batch 3rd-party tested Research use only
Keep the framing mechanistic

Ipamorelin is best described as GHSR / growth-hormone-secretagogue research. Human evidence is limited (an early Phase 2 program did not establish benefit). Avoid “muscle,” “recovery” or “fat-loss” framing.

Technical profile

CompoundIpamorelin
ClassSynthetic pentapeptide (5 amino acids); selective ghrelin-receptor (GHS-R1a) agonist
Molecular formulaC38H49N9O5
Molecular weight711.9 g/mol
CAS number170851-70-4
PubChem CID9831659
Form suppliedLyophilized powder, sealed vial
StorageLyophilized: 2–8 °C, protected from light.
VerificationHPLC purity ≥99%, sterility, endotoxins, heavy metals — documented on the batch COA

Evidence at a glance

Research evidence is not one category. Human, animal (preclinical) and in-vitro / mechanistic data differ in strength — often sharply. VP Peptides separates them so no single line overstates the whole picture. Ratings are deliberately conservative and describe the published evidence base, not any effect in humans.

Human clinical
Insufficient
Animal / preclinical
Moderate
In-vitro / mechanistic
Moderate
Regulatory statusIpamorelin, a growth-hormone secretagogue, has never been FDA-approved for any indication; it reached Phase 2 (e.g. postoperative ileus) without demonstrating significant efficacy and appears on the FDA's Category 2 bulk drug substances list, restricting compounding.
What remains unknown
  • Human efficacy for any indication — the limited Phase 2 human data did not establish benefit
  • Long-term human safety of the research material
  • Identity and purity of research-grade material sold as ipamorelin

What does the research literature cover?

Ipamorelin appears in the growth-hormone-secretagogue literature primarily as a tool compound for studying receptor selectivity. Published preclinical work has examined it in the context of:

Important context: the published evidence base is preclinical (cell and animal models). Ipamorelin has no approved human use in any jurisdiction. Summaries here describe what researchers have studied — they are not claims about effects in humans.

Why purity matters for ipamorelin research

Receptor-selectivity research is only as reliable as the material in the vial. Truncated sequences, deletion impurities, or endotoxin contamination confound binding and functional assays. Every VP Peptides ipamorelin batch ships with a Certificate of Analysis documenting ≥99% HPLC purity plus sterility, endotoxin and heavy-metal testing from independent third-party testing.

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Frequently asked questions

Is ipamorelin approved for human use?

No. Ipamorelin is not approved by the FDA or any other regulatory agency for human use. It is supplied strictly as a research chemical for in-vitro and laboratory investigation. It is not a drug, supplement, or food ingredient.

What does "selective" mean in the ipamorelin literature?

In preclinical studies, ipamorelin activated the ghrelin receptor (GHS-R1a) while showing minimal effect on cortisol and prolactin signaling compared with earlier-generation secretagogues. That selectivity profile is why it is frequently used as a reference compound in receptor-pharmacology research.

How should ipamorelin be stored in the lab?

Lyophilized vials should be kept at 2–8 °C and protected from light.

What is ipamorelin's status in competitive sport?

Growth-hormone secretagogues are listed as prohibited substances under the World Anti-Doping Agency (WADA) Prohibited List. This is noted for informational purposes only; VP Peptides materials are supplied solely for laboratory research.

Ghrelin-receptor / GH-secretagogue science, in context

Ipamorelin belongs to a family of small synthetic peptides known as growth-hormone secretagogues — molecules that engage the growth-hormone-secretagogue receptor type 1a (GHS-R1a), the same G-protein-coupled receptor activated by the endogenous hormone ghrelin. In the receptor-pharmacology literature, ipamorelin is characterized as a selective agonist at this receptor. When it binds GHS-R1a on somatotroph cells of the anterior pituitary, the receptor couples through Gq/11 signaling to phospholipase C, generating intracellular second messengers that, in preclinical models, are associated with release of growth hormone from pituitary stores (Raun et al., 1998).

The property most frequently emphasized in the literature is selectivity. In the original preclinical characterization, ipamorelin stimulated growth-hormone release with little concurrent effect on cortisol- or prolactin-related signaling relative to earlier secretagogues — a receptor-level distinction that made it a useful reference compound for studying GHS-R1a activation itself. Broader reviews situate this receptor within a wider signaling network, describing its coupling behavior and its interactions with other G-protein-coupled receptors (Howick et al., 2022).

Human clinical evidence, by contrast, remains limited. Ipamorelin advanced into an early Phase 2 program — a randomized, placebo-controlled study in postoperative ileus after bowel resection — but that trial did not demonstrate a significant benefit over placebo on its efficacy endpoints (Beck et al., 2014). No subsequent program has established a human therapeutic use, and ipamorelin is not approved by the FDA or any other regulatory authority for any indication.

For laboratory researchers, this places ipamorelin as a mechanistic tool for probing ghrelin-receptor signaling and secretagogue pharmacology — not as an agent with demonstrated human outcomes.

Selected research references

Related research compounds

Research use only. All products described on this page are furnished for laboratory research purposes only and are not for human or veterinary use, not for use in food or cosmetics, and not for any diagnostic or therapeutic application. Nothing on this page is medical advice or a claim of safety or efficacy in humans. Research summaries reference publicly available preclinical literature; specific citations are listed in the references above.