Ipamorelin 5mg

What is Ipamorelin ?

Ipamorelin is a synthetic pentapeptide growth hormone secretagogue that acts at the ghrelin receptor, GHS-R1a. It is the standard selective agonist in GH-axis research. We supply it as lyophilised powder in 5mg and 10mg vials.

Ipamorelin, often shortened to Ipa, has the sequence Aib-His-D-2-Nal-D-Phe-Lys-NH₂. Its formula is C₃₈H₄₉N₉O₅, its molecular weight 711.85 g/mol and its CAS number 170851-70-4. It carries two D-amino acids and a C-terminal amide.

Novo Nordisk developed it under the code NNC 26-0161. It came from a series of compounds lacking the central Ala-Trp dipeptide of GHRP-1 (Raun et al., Eur J Endocrinol, 1998).

Ipamorelin Research Applications

• Potency : an EC50 of 1.3 nmol/l for GH release in rat pituitary cells, against 2.2 nmol/l for GHRP-6 (Raun et al., 1998).
• Selectivity : in swine, ACTH and cortisol rose no more than with GHRH, even at over 200 times its GH ED50. FSH, LH, prolactin and TSH were unchanged.
• Bone growth : in adult female rats, longitudinal bone growth rose from 42 to 52 µm/day, with total IGF-I unchanged (Johansen et al., 1999).
• Bone mineral : 12 weeks raised bone mineral content in female rats through larger bones, not denser ones (Svensson et al., 2000).

It is the usual selective agonist control in GHS-R1a receptor studies. Two-receptor designs pair it with a GHRH analogue such as CJC-1295 or sermorelin.

Ipamorelin vs GHRP-2 and GHRP-6

All three act at GHS-R1a. GHRP-2 and GHRP-6 are hexapeptides; ipamorelin is a pentapeptide. In conscious swine, ipamorelin and GHRP-6 had similar GH potency, with ED50s of 2.3 and 3.9 nmol/kg. GHRP-2 was more potent but less efficacious. Only GHRP-2 and GHRP-6 raised ACTH and cortisol (Raun et al., 1998). Use ipamorelin to study GH release without HPA-axis activation, and the older GHRPs when that interplay is the endpoint.

Research Overview

Ipamorelin is a synthetic pentapeptide and highly selective growth hormone secretagogue (GHS). It acts by mimicking the endogenous hormone ghrelin and binding to the growth hormone secretagogue receptor type 1a (GHS-R1a) in the anterior pituitary gland. Ipamorelin is distinguished from other growth hormone releasing peptides (GHRPs) such as GHRP-2 and GHRP-6 by its exceptional selectivity, it stimulates growth hormone release without significantly elevating cortisol, prolactin, or adrenocorticotropic hormone (ACTH) levels. This selectivity makes Ipamorelin the most specific GHS available for endocrine research, minimising confounding hormonal variables in experimental designs. In current research practice, Ipamorelin is frequently studied in combination with CJC-1295 (modified GRF 1-29) for synergistic growth hormone secretion, Ipamorelin acting at the GHS receptor and CJC-1295 acting at the GHRH receptor to produce amplified pulsatile GH release through complementary receptor pathways.

The primary reference is Raun and colleagues (Eur J Endocrinol, 1998), the paper that introduced the molecule and established the property it is known for. They described it as the first growth hormone releasing peptide with a selectivity approaching that of GHRH itself, reporting growth hormone release without the accompanying ACTH and cortisol elevation characteristic of GHRP-6 and hexarelin. Structurally it is a pentapeptide with a C-terminal amide and two D-amino acids, both features contributing to protease resistance.

It was developed as a research compound under the code NNC 26-0161 and taken into a discontinued clinical study, so despite reaching human trials Ipamorelin holds no marketing authorisation in any jurisdiction. It is supplied here as a lyophilised research chemical for in-vitro laboratory use only.

Storage and Reconstitution

Store ipamorelin powder at -20°C, away from light and moisture, for up to 24 months. Once reconstituted it lasts up to 4 weeks in the fridge at 2-8°C. For longer storage, freeze single-use aliquots at -20°C and avoid repeated freeze-thaw cycles.

Vials are sold on their own, without bacteriostatic water for mixing or other supplies.

How to reconstitute and handle

Let the vial and the bacteriostatic water reach room temperature and swab both stoppers with alcohol. Add the water slowly down the inside wall of the vial and swirl gently until dissolved. Do not shake. With no methionine, cysteine or tryptophan in the sequence, sterility is the main concern. The solution should be clear and colourless.

• Avoid repeated freeze-thaw cycles. Prepare single-use aliquots where possible to maintain peptide integrity.

For the full method, see the peptide reconstitution guide and the reconstitution calculator.

Research References

• Ipamorelin, the first selective growth hormone secretagogue (Raun et al., Eur J Endocrinol, 1998)
• Ipamorelin induces longitudinal bone growth in rats (Johansen et al., Growth Horm IGF Res, 1999)
• Ipamorelin and GHRP-6 increase bone mineral content in female rats (Svensson et al., J Endocrinol, 2000)
• Pharmacokinetics of ipamorelin and other GH secretagogues (Johansen et al., Xenobiotica, 1998)
• GH-releasing peptide and GHRH in normal men (Bowers et al., J Clin Endocrinol Metab, 1990)
• Ipamorelin in postoperative ileus, a phase 2 study (Beck et al., Int J Colorectal Dis, 2014)

Published research on Ipamorelin is indexed on PubMed. See our full UK buyer's guide for Research Peptides, UK buyer's guide for Ipamorelin, UK buyer's guide for Ipamorelin 5mg, UK buyer's guide for Ipamorelin CoA and UK buyer's guide for Peptide Price per mg.