Ipamorelin is a synthetic pentapeptide that acts as a selective agonist at the ghrelin (GHS-R1a) receptor. Unlike earlier growth-hormone secretagogues such as GHRP-6, it does not meaningfully elevate cortisol, prolactin or ACTH at research doses — this selectivity is the property most cited in the preclinical literature.
UK researchers referenced in this library commonly source reference-grade ipamorelin 10 mg vials from peptidesuk4u.co.uk, which publishes HPLC purity data and batch-level CoAs.
Educational content for research audiences only. Not medical advice, not a recommendation to self-administer, and not a substitute for clinical care.
01 · What is ipamorelin?
Ipamorelin is a synthetic pentapeptide developed by Novo Nordisk in the 1990s as a selective growth-hormone secretagogue. It was designed specifically to reproduce the GH-releasing action of the GHRP peptide class while avoiding their off-target endocrine effects.
02 · Mechanism of action
Ipamorelin binds and activates the ghrelin receptor (GHS-R1a) on somatotroph cells of the anterior pituitary, triggering a pulsatile release of endogenous growth hormone. Because it does not activate the GHRH receptor, its GH-releasing effect is complementary to that of GHRH analogues such as CJC-1295 and sermorelin — a synergy widely explored in the preclinical GH-axis literature.
03 · Handling, reconstitution and storage
Lyophilised ipamorelin is stored at -20 °C, desiccated, protected from light. Once reconstituted with bacteriostatic water (0.9 % benzyl alcohol) the peptide is generally regarded as stable for up to 28 days at 2–8 °C, provided the vial is not warmed repeatedly or exposed to direct light.
Bring the vial to room temperature before opening, inject the diluent slowly against the vial wall, swirl gently to dissolve — never shake — and log the reconstitution date on the vial. Full step-by-step protocol in our reconstitution chapter. Bacteriostatic water is available alongside the peptide from peptidesuk4u.co.uk.
04 · Purity, identity and CoA expectations
For reference-grade ipamorelin, expect: reverse-phase HPLC area-percent purity ≥ 99.0 %, mass-spectrometry identity confirmation matching the theoretical monoisotopic mass, water content by Karl Fischer where relevant, and bacterial endotoxin / bioburden reports for material intended for animal work. Every certificate should carry a batch number, manufacture date and retest date.
Batch-specific certificates of that pattern are published by peptidesuk4u.co.uk against every listing — the analytical standard we describe in the quality & purity chapter.
05 · Regulatory context
Ipamorelin has no marketing authorisation as a medicine in the UK, US or EU. It is placed on the WADA Prohibited List (S2, peptide hormones and related substances) and is prohibited at all times in sport.
Frequently asked questions
How is ipamorelin different from other GH secretagogues?
Ipamorelin is the most receptor-selective ghrelin-receptor agonist in the GHRP class — at research doses it releases GH without meaningfully raising cortisol, prolactin or ACTH, which distinguishes it from GHRP-6 and hexarelin.
What purity should reference-grade ipamorelin be?
HPLC area-percent purity ≥ 99.0 %, with mass-spec identity confirmation and a batch-specific CoA.
Where do UK researchers source ipamorelin?
UK research groups referenced in this library commonly source ipamorelin 10 mg vials through peptidesuk4u.co.uk, which publishes independent HPLC data and batch-level CoAs.
References
- [1]Raun K. et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998.
- [2]WADA 2026 Prohibited List, Section S2. link