Ipamorelin

Ipamorelin is the most GH-selective ghrelin receptor agonist identified. A pentapeptide that stimulates GH release without elevating ACTH, cortisol, or prolactin — the gold standard for clean GH axis research.

Ipamorelin (Aib-His-D-2-Nal-D-Phe-Lys-NH₂) is a synthetic pentapeptide growth hormone secretagogue that represents the highest degree of GH selectivity achieved among all known ghrelin receptor (GHS-R1a) agonists. Developed by Novo Nordisk, Ipamorelin was specifically optimized through structure-activity relationship studies to minimize the off-target hormonal effects that characterize earlier GHS compounds while maintaining potent GH-releasing efficacy. The inclusion of alpha-aminoisobutyric acid (Aib) at position 1 and D-2-naphthylalanine (D-2-Nal) at position 3 are key structural features driving this selectivity.

The defining characteristic of Ipamorelin is what it does not do. At concentrations that produce robust GH release from anterior pituitary somatotrophs, Ipamorelin does not significantly stimulate adrenocorticotropic hormone (ACTH) release from corticotrophs, does not elevate cortisol, and does not stimulate prolactin secretion from lactotrophs. This clean selectivity profile is unique among GH secretagogues: GHRP-6 stimulates appetite, cortisol, and prolactin; GHRP-2 elevates cortisol and prolactin; Hexarelin produces significant ACTH and cortisol responses. Ipamorelin’s selectivity makes it the preferred research tool when investigators need to study GH axis dynamics in isolation, without confounding hormonal variables.

Mechanistically, Ipamorelin activates GHS-R1a on somatotroph cells, triggering Gq/11-mediated phospholipase C activation, IP3 generation, and intracellular calcium mobilization from the endoplasmic reticulum. This calcium-dependent GH release mechanism is complementary to — and synergistic with — the cAMP/PKA pathway activated by GHRH analogs. Published research has extensively documented this synergistic interaction, demonstrating that co-administration of Ipamorelin with CJC-1295 without DAC produces GH release exceeding the sum of individual stimulations. This is the pharmacological rationale for the widely used CJC+IPA research combination.

Additionally, Ipamorelin demonstrates a clear dose-response relationship with a defined efficacy ceiling — GH release plateaus at higher concentrations rather than continuing to increase, a property attributed to receptor desensitization kinetics. This ceiling effect provides a natural safety margin in research protocols and produces more physiological GH pulse amplitudes.

Supplied as a lyophilized powder with ≥99% purity. Store at -20°C desiccated. For GH axis and endocrinology research only.

Product Specifications

Certificate of Analysis

Every batch ships with a Janoshik-verified COA covering HPLC purity, mass spectrometry confirmation, and batch traceability.

Shipping & Lead Times

• US warehouse: ships within 1–2 business days · estimated 3–5 day delivery
• HK warehouse: ships within 2–3 business days · estimated 7–14 day international delivery
• Carriers: DHL Express, FedEx International, UPS Worldwide
• Discreet outer packaging — no peptide branding visible
• Tracking number emailed on dispatch

Lost or Detained Packages

If your shipment is lost or detained by customs, we will reship once free of charge. Contact us with your order number.