Ipamorelin vs GHRP-2

Both hit the same receptor, and selectivity is the whole difference

Both are ghrelin receptor agonists that trigger growth hormone release, so on paper they do the same job. Ipamorelin is the selective one: human studies found it raised growth hormone without meaningfully moving cortisol, prolactin or ACTH, and without much appetite effect. GHRP-2 is stronger but less clean, nudging cortisol and prolactin upward and stimulating hunger. GHRP-2 is actually approved in Japan as a diagnostic test; ipamorelin reached phase 2 for post-surgical bowel recovery, missed its endpoint, and was dropped.

Pituitary secretory cell with granular cytoplasm, a large nucleus and tiny secretory vesicles, macro cellular view.

Ipamorelin Growth hormone Full entry →

Midsagittal human brain cutaway showing the hypothalamic-pituitary region.

GHRP-2 Growth hormone Pralmorelin, KP-102 Full entry →

Ipamorelin compared with GHRP-2
	Ipamorelin	GHRP-2
Evidence behind it	Human trials	Human trials
Worth knowing	The phase 2 bowel trials did not meet their endpoint and development stopped.	Also nudges cortisol and prolactin up. Appetite stimulation is strong enough to be unwanted for some.
Approval	In trials	Approved · Japan
Category	Growth hormone	Growth hormone
What it is	A five-amino-acid peptide that activates the ghrelin receptor to release growth hormone. It is known for selectivity: in studies it raised growth hormone without meaningfully changing cortisol, prolactin or ACTH, and with little effect on appetite.	A six-amino-acid synthetic peptide that activates the ghrelin receptor, prompting the pituitary to release growth hormone. Like ghrelin it also increases appetite, and it can raise cortisol and prolactin somewhat, so it is less selective than ipamorelin.
How it works	Binds the pituitary ghrelin receptor to trigger pulsatile growth hormone release, with notably little effect on cortisol, prolactin or appetite.	Activates the ghrelin receptor on the pituitary, triggering growth hormone release. It also nudges cortisol and prolactin upward, which is what separates it from the more selective ipamorelin.
What studies report	Clean growth hormone release without raising cortisol, prolactin or ACTH in human studies Studied for restarting bowel movement after abdominal surgery	Reliable growth hormone release in human studies, used diagnostically in Japan Increased appetite and food intake Rise in IGF-1 with repeated use
Dosing	From studies 0.1–2 mg, intravenous, single dose — Human pharmacology studies of growth hormone response. Dose-dependent GH release without raising cortisol or prolactin Reported, not evidence 200–300 mcg, usually before bed to match the natural GH pulse Commonly 5 days on, 2 off Almost always paired with CJC-1295 without DAC	From studies 100 mcg, intravenous — Diagnostic GH stimulation testing (approved use in Japan). Reliable GH release Reported, not evidence 100–200 mcg, up to a few times daily Chosen over GHRP-6 when appetite stimulation is unwanted
Why people take it	Lean muscle preservationFat lossTissue repairRecoveryGrowth hormone release without appetite or cortisol effectsBody composition	Growth hormone releaseAppetite stimulationRecovery and sleep
In practice	Typically taken at night to mimic the body's natural growth hormone pulse Very commonly stacked with CJC-1295 — the pairing is close to a default Preferred over GHRP-2 and GHRP-6 by people who dislike hunger and cortisol effects Sold pre-blended with tesamorelin in a single vial, pairing a secretagogue with a growth hormone releasing factor	Chosen over GHRP-6 when appetite stimulation is unwanted
Route	Subcutaneous injection, from reconstituted lyophilised powder	Subcutaneous injection, from reconstituted lyophilised powder

Rows describing reported use say what people do, not what has been shown to work. Evidence strength is graded the same way across the whole library, so the two columns are directly comparable.

Read the full entries

Ipamorelin → GHRP-2 → Open this in the compare tool →

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Educational information only. Nothing here is medical advice, a dosing protocol, or a recommendation to use any compound. Comparing two compounds is not a suggestion to take either one. Talk to a licensed clinician before acting on anything you read here. How to read these entries.