What it is
Ipamorelin is a growth hormone secretagogue — a compound studied for its ability to trigger the release of growth hormone (GH) from the body's own pituitary gland, rather than supplying growth hormone directly. It is described as selective because, unlike some other compounds in this category, it is studied for stimulating GH release without significantly raising cortisol or prolactin, two hormones often affected by less selective secretagogues. It is categorized as a growth hormone compound in the PeptidesAI encyclopedia.
How it's thought to work
Ipamorelin is studied for selectively stimulating growth hormone release from the pituitary gland by acting on the ghrelin receptor, the receptor that the hormone ghrelin normally acts on. Research describes this as happening without significantly affecting cortisol, prolactin, or ACTH (adrenocorticotropic hormone) levels. That selectivity — releasing growth hormone while leaving those other hormone levels largely unaffected — is what distinguishes ipamorelin within this class of compounds.
What the research says
Clinical studies on ipamorelin show selective growth hormone release without meaningful elevation of cortisol or prolactin. That is the specific pairing of findings — GH release on one hand, and a lack of effect on those other two hormones on the other — that the clinical research on ipamorelin is described as showing.
Reported side effects
Reported side effects include increased hunger, water retention, tingling or numbness in the extremities, and headache. Joint pain is also reported, but rarely, making it the least commonly reported of the effects listed here.
Reconstitution
Ipamorelin is supplied as a lyophilized (freeze-dried) powder and is typically reconstituted with bacteriostatic (BAC) water before use. It commonly comes in 2 mg and 5 mg vials, and reconstitution follows the same dilution math regardless of which vial size is on hand.
Worked example. A 5 mg vial is 5,000 mcg. Reconstituted with 2 mL of BAC water, that works out to 5,000 mcg ÷ 2 mL = 2,500 mcg/mL. On a U-100 insulin syringe, where each unit is 0.01 mL, that means each unit holds 2,500 × 0.01 = 25 mcg. A 2 mg vial reconstituted with less water would produce a different concentration; the exact figure depends on how much BAC water is used. Use the peptide reconstitution calculator to work out the concentration and units for any vial size and water volume, including a 2 mg vial.
Important notes
That empty-stomach dependency is specific to ipamorelin's studied mechanism and is not universal across all peptides covered elsewhere on this site.
Frequently asked questions
These questions cover the same ground as the sections above, in a shorter format.
What is ipamorelin?
A selective growth hormone secretagogue studied for stimulating GH release from the pituitary without significantly raising cortisol or prolactin. It is a research compound, not approved by the FDA for human use.
How is ipamorelin thought to work?
It is studied for acting on the ghrelin receptor to stimulate GH release from the pituitary gland, without significantly affecting cortisol, prolactin, or ACTH levels.
What does the research on ipamorelin say?
Clinical studies show selective growth hormone release without meaningful cortisol or prolactin elevation.
What are the reported side effects?
Increased hunger, water retention, tingling or numbness in the extremities, and headache. Joint pain is reported rarely.
How many mcg is one unit from a 5 mg ipamorelin vial?
With 2 mL of BAC water, a 5 mg vial is 2,500 mcg/mL, so one unit on a U-100 syringe (0.01 mL) holds 25 mcg.
The full entry, plus the calculator
The PeptidesAI app has the complete encyclopedia entry for ipamorelin — one of 70 compounds covered — including protocol notes, plus the reconstitution calculator, a dose log and reminders. Free to download on iPhone.
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