Ipamorelin Peptide Pen (GH Secretagogue) | 20mg

Ipamorelin is a synthetic pentapeptide growth hormone secretagogue, supplied here pre-mixed at 20 mg in a 3 ml stabilised cartridge at a stated 6.67 mg/ml. No reconstitution step and no separate diluent.

What ipamorelin is

The structure is Aib-His-D-2-Nal-D-Phe-Lys-NH₂ — five residues, three of which are non-natural. Aib is α-aminoisobutyric acid, a residue that constrains the peptide backbone; D-2-Nal is a D-configured naphthylalanine; and the C-terminus is amidated. None of that is decoration: the unnatural residues and the D-amino acids are what make a five-residue peptide resistant to proteases that would otherwise clear it immediately.

It acts at the ghrelin receptor (growth hormone secretagogue receptor, GHS-R1a), not at the GHRH receptor. That is the substantive distinction from tesamorelin, which is a GHRH analogue. Both reach growth hormone release; they arrive at it through different receptors, and in laboratory models the two stimuli are not interchangeable.

Why "selective" is the defining word

Ipamorelin was characterised in 1998 as the first selective growth hormone secretagogue, and that phrase carries specific meaning. The earlier secretagogues in this family — GHRP-6 and GHRP-2 — also raised adrenocorticotropic hormone, cortisol and prolactin at concentrations that stimulated growth hormone release. Ipamorelin, in the original characterisation work, released growth hormone without that accompanying rise.

This selectivity is the reason it persists as a tool compound: it lets an experiment isolate GHS-R1a-mediated growth hormone release from confounding activity on the hypothalamic–pituitary–adrenal axis. When ipamorelin appears in a study design, that is usually why.

Ipamorelin pen: the same thing under a shorter name

Most people searching for this product type “ipamorelin pen” rather than the full compound name, and the two mean the same thing. A ipamorelin pen is a pre-filled ipamorelin cartridge in a dial-dosing pen, as opposed to lyophilised powder in a vial.

This pen holds 20 mg in a sealed 3 ml cartridge, at 6.67 mg/ml. The dial is graduated at 5 clicks = 300  mcg. Those are device figures — what the mechanism displaces, not what should be dispensed.

Applications in research

• GHS-R1a receptor pharmacology. Binding and functional assays at the ghrelin receptor, where a selective agonist is required as a reference against the less selective GHRP series.
• Somatotroph culture models. Pituitary cell preparations with growth hormone release as the measured output, run alongside GHRH analogues to compare the two receptor routes.
• Peptidase resistance studies. Comparative degradation work in which the Aib and D-amino-acid substitutions are the structural variables under examination.
• Skeletal growth models. Longitudinal bone growth in rodent work, one of the original published characterisations of the compound.

Is ipamorelin legal in the UK?

Ipamorelin is not a licensed medicine anywhere. It entered clinical development and did not complete it, and it holds no marketing authorisation from the MHRA, EMA or FDA.

It is not a controlled drug under the Misuse of Drugs Act 1971, so buying and possessing it in the UK for laboratory research is lawful. Supplying it for human or veterinary consumption is not, and would engage the Human Medicines Regulations 2012. Separately, and for anyone working near regulated sport: growth hormone secretagogues sit on the WADA Prohibited List under S2 and are prohibited at all times.

What you are actually comparing between listings

• Total mass. This cartridge holds 20 mg. The common presentation elsewhere is a 5 mg vial, so one unit here carries roughly four times the peptide of a typical listing.
• Format. Pre-mixed solution at a stated 6.67 mg/ml against lyophilised powder requiring reconstitution, with the handling variance that introduces between preparations.
• Cost per milligram. At £110 for 20 mg this works out at £5.50 per mg.

Handling and storage

Store at 2–8 °C and protect from light. Keep the cartridge sealed until use, then upright, and observe aseptic technique. Do not freeze. Short constrained peptides of this kind are comparatively stable in solution, but freeze–thaw cycling still promotes aggregation and should be avoided. Orders placed before 2pm are dispatched the same working day, cold-packed, in plain outer packaging.

References

Literature on the molecule. These describe ipamorelin as a compound and none is a claim about this product.

1. Raun K, Hansen BS, Johansen NL, et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998;139(5):552–61. PMID 9849822.
2. Johansen PB, Nowak J, Skjaerbaek C, et al. Ipamorelin, a new growth-hormone-releasing peptide, induces longitudinal bone growth in rats. Growth Horm IGF Res. 1999;9(2):106–13. PMID 10373343.

Research use only

This material is supplied strictly for in-vitro research and analytical purposes. It is not for human or veterinary administration and not for any diagnostic or therapeutic application. It holds no marketing authorisation in any territory. Confirm the current regulatory position before drafting institutional documentation, and clear the material through your own ethics, COSHH and biosafety processes before ordering.