Ipamorelin

Overview

Ipamorelin is a synthetic pentapeptide (Aib-His-D-2-Nal-D-Phe-Lys-NH₂) developed in the late 1990s by Novo Nordisk researchers as part of a major chemistry program to identify selective growth hormone secretagogues. Published in 1998, it was distinguished as the first highly selective GHS-R1a (ghrelin receptor) agonist, notably lacking the central Ala-Trp dipeptide found in earlier GHRPs, a structural change that eliminated the ACTH/cortisol stimulation seen in earlier-generation peptides [1].

Unlike sermorelin, which acts at the GHRH receptor, ipamorelin targets the ghrelin receptor (GHS-R1a). Both ultimately stimulate pituitary GH release, but through distinct receptor pathways. Ipamorelin also exerts prokinetic effects on gastrointestinal motility via GHS-R1a receptors in the GI tract, which led to its evaluation in two Phase II clinical trials for postoperative bowel dysfunction.

Ipamorelin has never received FDA approval and is not commercially marketed. It is sold as a research compound and is widely offered by compounding pharmacies for off-label use in anti-aging and men's health contexts. There is no standardized, guideline-endorsed dosing regimen for healthy adults [6].

Research Areas and Claims

Ipamorelin's evidence base spans selective GH secretagogue pharmacology, preclinical models of bone/muscle catabolism, and two Phase II gastrointestinal trials in humans. Longevity and body composition claims used in clinic marketing extend considerably beyond what published evidence supports.

• Selective GH Secretion (No HPA Axis Activation): Ipamorelin's defining characteristic: it stimulates pulsatile GH release without meaningfully elevating cortisol, ACTH, or prolactin, a selectivity advantage over earlier GHRPs such as GHRP-2 and GHRP-6 [1].

• GI Prokinetic Activity: GHS-R1a receptors in the GI tract mediate ipamorelin's prokinetic effects. This rationale drove two Phase II RCTs in postoperative bowel dysfunction (the only controlled human trials published to date) [2][14].

• Protection Against Glucocorticoid-Induced Catabolism (Preclinical): In animal models, ipamorelin counteracted glucocorticoid-induced decreases in muscle strength and bone formation, the evidence basis for body composition and bone density claims, though these are preclinical findings [4].

• Muscle Growth, Fat Loss, Sleep, Anti-Aging (Clinic Claims): Commonly promoted in compounding/wellness contexts. No published randomized controlled trials in healthy humans support these outcomes specifically for ipamorelin. GH/IGF-1 elevation is established; translation to hard clinical endpoints is not [6].

Mechanism of Action

1. Selective GHS-R1a Agonism: Ipamorelin binds selectively to the ghrelin receptor (GHS-R1a) on pituitary somatotrophs. This directly stimulates pulsatile GH secretion. The selectivity is high; unlike GHRP-2 and GHRP-6, ipamorelin does not significantly activate GHS-R subtypes responsible for ACTH, cortisol, or prolactin release [1].
2. Pulsatile GH Release with Preserved Feedback: By acting at the pituitary level via GHS-R1a, ipamorelin stimulates GH in a pulsatile pattern that preserves somatostatin-mediated negative feedback. This is mechanistically analogous to sermorelin's preservation of physiological GH axis regulation, though via a different receptor pathway [7].
3. Downstream IGF-1 Elevation: GH secreted in response to ipamorelin stimulates hepatic IGF-1 production. IGF-1 is the primary downstream biomarker monitored in clinical and compounding contexts, and mediates the anabolic and growth-related effects attributed to GH axis activation [7].
4. GI Prokinetic Effects: GHS-R1a receptors are also expressed in the gastrointestinal tract, where ipamorelin promotes gastric emptying and GI motility. This is the mechanism underlying its evaluation in postoperative ileus and bowel dysfunction trials [3].

Clinical Trials

Ipamorelin has been evaluated in human subjects in pharmacokinetic profiling and two Phase II randomized controlled trials. All controlled human trials targeted gastrointestinal endpoints; no large-scale RCTs have evaluated ipamorelin for body composition, longevity, or anti-aging outcomes in healthy adults.

Administration Methods

• Subcutaneous (SC): The predominant route in compounding and off-label clinic practice. Often administered once or twice daily on an empty stomach to mimic physiological GH pulses. Not validated by published human RCTs for this indication [6].
• Intravenous (IV): Used in both Phase II clinical trials and in PK/PD profiling. Not the route used in compounding practice [2][14].

Vendor Directory

Data collected February 2026. Vendors are separated by availability of public pricing. Prices subject to change.

Injectable: Standalone (SC), With Pricing

Combination Products (with Ipamorelin)

All combination products below use CJC-1295 WITHOUT DAC blended with ipamorelin. See the CJC-1295 page for the same table from the CJC-1295 perspective.

No Public Pricing / B2B / Inactive

* Data Notes: Data collected February 2026. All products sold strictly for in-vitro research purposes. $/mg calculated from listed catalog price ÷ mg per vial. Biolongevity Labs price reflects a sale active as of data collection (ends Feb 28, 2026); regular price ~$8.00/mg. * Prime Peptides price unconfirmed; verify directly before purchasing. Prices subject to change.