Ipamorelin
What ipamorelin is
Ipamorelin is a pentapeptide growth hormone secretagogue, meaning it acts on the body's own growth hormone release mechanism rather than supplying growth hormone directly. It is an agonist at the ghrelin receptor, sometimes written GHSR.
What distinguishes it within its class is selectivity. Earlier secretagogues such as GHRP-6 and GHRP-2 also raise cortisol and prolactin alongside growth hormone. Ipamorelin was developed to minimise that, and published work reports comparatively little effect on either. That selectivity is the reason it is studied where a cleaner signal is wanted.
At a glance
| Class | Pentapeptide growth hormone secretagogue |
|---|---|
| Target | Ghrelin receptor (GHSR) |
| Presentation | Lyophilised powder, or pre-filled SerenQ pen |
| Reported half-life | Approximately 2 hours |
| Storage | 2 to 8 °C |
Ghrelin against GHRH
The secretagogues divide into two mechanisms and it is worth keeping them straight, because the names give no clue.
| Receptor | Compounds |
|---|---|
| Ghrelin (GHSR) | Ipamorelin, GHRP-2, GHRP-6, MK-677 |
| GHRH | Sermorelin, CJC-1295 |
Because the two act on separate pathways, they are frequently studied in combination rather than as substitutes for one another. The pairing of ipamorelin with CJC-1295 is common in the literature for exactly that reason, and is sold as a combined SerenQ pen.
Reconstitution
Bring the vial to room temperature. Swab the stopper, draw your diluent, and let it run down the inside wall of the vial rather than striking the powder directly. Allow it to dissolve without agitation, swirling gently if slow. Never shake.
A correctly reconstituted vial is clear and colourless. Concentration is total peptide divided by diluent volume: a 10mg vial with 2ml gives 5mg/ml, so 10 units on a U-100 syringe carries 500mcg. With 5ml it gives 2mg/ml and those same units carry 200mcg.
Ipamorelin's short half-life is worth factoring into how much you reconstitute at once. A vial made up at high concentration and drawn from infrequently spends longer in solution than one made up as needed, and time in solution is what degrades peptides.
Storage
Sealed and lyophilised, 2 to 8 °C away from light. Dry material is stable over long periods because hydrolysis requires water.
Reconstituted, refrigerate upright and dark, and never freeze. Freeze-thaw cycles shear peptide chains and the damage is not visible in the solution.
Where the pre-filled SerenQ pen is used there is no reconstitution step at all. The solution is made up at manufacture in a sealed cartridge, which removes both the arithmetic and the repeated stopper punctures. See pens compared with vials.
Frequently asked
Is ipamorelin HGH? No. Growth hormone is a 191 amino acid protein given directly. Ipamorelin is a five amino acid peptide that acts on the release mechanism instead.
Why is it paired with CJC-1295? They work through different receptors, ghrelin and GHRH respectively, so the combination is studied for a complementary effect rather than a duplicated one.
How does it differ from GHRP-2 and GHRP-6? Same receptor, but ipamorelin is reported as more selective, with less effect on cortisol and prolactin.
Is it the same as MK-677? Same receptor, different molecule. MK-677 is a non-peptide taken orally with a roughly 24 hour half-life; ipamorelin is a peptide requiring injection with a half-life around two hours.