Ipamorelin — wholesale 10-vial kits

Research context

Ipamorelin is a member of the growth hormone-releasing peptide (GHRP) family, small synthetic peptides that activate the ghrelin receptor GHS-R1a on pituitary somatotrophs. It was described in 1998 as the first selective growth-hormone secretagogue: in the original pharmacology it released growth hormone without the accompanying rises in ACTH and cortisol seen with earlier GHRPs such as GHRP-2 and GHRP-6.

Origin and selectivity data. Ipamorelin, development code NNC 26-0161, came out of a Novo Nordisk chemistry program and was identified within a series of compounds that lack the central Ala-Trp dipeptide of GHRP-1 (Raun et al., European Journal of Endocrinology, 1998). In primary rat pituitary cells it released GH with potency and efficacy similar to GHRP-6 (EC50 about 1.3 nM), and profiling with GHRP and GHRH antagonists showed it acts through the GHRP-like receptor rather than the GHRH receptor. In conscious swine none of the secretagogues tested changed FSH, LH, prolactin or TSH, but GHRP-6 and GHRP-2 raised ACTH and cortisol while ipamorelin did not, even at more than 200-fold the level needed for half-maximal GH release. A rat pharmacokinetic comparison reported systemic plasma clearance about five-fold lower than GHRP-6, with mainly urinary rather than biliary excretion (Johansen et al., Xenobiotica, 1998).

Molecular design. Ipamorelin is a pentapeptide, Aib-His-D-2-Nal-D-Phe-Lys-NH₂, built almost entirely from non-standard building blocks: α-aminoisobutyric acid at the N-terminus, D-2-naphthylalanine, D-phenylalanine, and a C-terminal amide. The D-residues and the α,α-disubstituted Aib resist proteolysis, the bulky naphthyl and phenyl side chains supply the aromatic contacts this receptor family needs, and the free lysine ε-amine gives the molecule its basic charge. Dropping the Ala-Trp pair found in the hexapeptide GHRPs is the change associated with its selectivity profile.

That selectivity is what makes it useful to researchers. Ipamorelin is used as a clean GHS-R1a agonist in receptor-signaling and pituitary cell models, as a comparator when profiling new secretagogues, and in rodent studies of ghrelin-receptor effects on bone formation and gastrointestinal motility. It is frequently paired with a GHRH-receptor agonist such as Mod GRF 1-29 to study the two receptors' combined effect.

U.S. regulatory status: ipamorelin is not an FDA-approved drug. Clinical development for postoperative ileus reached a Phase 2 proof-of-concept study published in 2014 and produced no approved product. In FDA's compounding records, ipamorelin acetate was placed in Category 2 under the 503B interim policy in September 2023, and its 503A nomination is listed as withdrawn; FDA's stated rationale cites aggregation and peptide-related impurity risk and the characterization complexity added by its unnatural amino acids. The material sold by WholesalePeptide.us is a research compound supplied only for in-vitro, analytical and preclinical laboratory research.

In analytical terms ipamorelin is straightforward: a short linear peptide with non-standard residues (Aib and D-2-naphthylalanine) that resolves cleanly on RP-HPLC and gives a single dominant [M+H]⁺ ion by LC-MS. That makes the COA's identity line easy to check against the theoretical mass from the PubChem formula shown on this page. Labs comparing secretagogues often order ipamorelin together with GHRP-2, GHRP-6 or hexarelin so the selectivity differences can be measured side by side.

Research areas

• Ghrelin receptor (GHS-R1a) agonism
• Selective growth-hormone secretagogue pharmacology
• Pituitary somatotroph cell models
• ACTH / cortisol selectivity profiling of secretagogues
• Rodent bone-formation and GI-motility models
• GHRH / GHS-R1a co-agonist studies

U.S. regulatory status of the compound (as an active ingredient): Not approved by the FDA. The material sold here is a research reference chemical, not a drug product.

Handling and storage

• Store lyophilized vials at −20 °C, sealed, protected from light and moisture.
• Let the vial reach room temperature before opening to limit condensation on the powder.
• Reconstitute in a sterile buffer appropriate to the assay, following your lab's SOP.
• Aliquot reconstituted material and freeze once; avoid repeated freeze–thaw.