Ipamorelin
The 'Clean' GHRP, Selective GH Release
Evidence grade 2 of 5, Thin. Read how the Atlas grades evidence.
The written rationale for this grade is still being prepared.
- FDA
- Not FDA-approved; reached early clinical trials, never marketed
Reference only. Not medical advice.
What can go wrong
GH secretagogues can raise IGF-1 and carry the general GH-excess concern set: insulin resistance, water retention, joint aches, carpal-tunnel symptoms. Selectivity reduces the cortisol/prolactin/appetite issues of older GHRPs but does not eliminate GH-related metabolic risk. Products are gray-market or compounded, with attendant purity uncertainty.
This is something to take to a clinician. The Atlas can tell you what is known about ipamorelin in general. It cannot tell you what is happening in your body, and the difference matters most for exactly the symptoms that bring people to this page.
Ipamorelin is a synthetic pentapeptide growth-hormone secretagogue that selectively agonizes the ghrelin receptor GHS-R1a to trigger the pituitary's own GH release. Originally developed by Novo Nordisk, it is prized in the peptide market for 'clean' GH stimulation: unlike older GHRPs, it does not meaningfully raise ACTH, cortisol, or prolactin even at high doses, and produces less appetite stimulation. Despite Phase I/II study history, it was never brought to market.
GH release without the hunger, cortisol, or prolactin, but no marketed product.
What people take it for
These are the reasons people give for taking it. They are not effects it has been shown to have.
How it is supposed to work
Ipamorelin binds GHS-R1a on the pituitary and hypothalamus, mimicking ghrelin's GH-releasing action while preserving pulsatility. Its defining property is selectivity: preclinical work showed it did not raise ACTH or cortisol even at doses over 200-fold the ED50 for GH release, and it spares prolactin, distinguishing it sharply from GHRP-6.
Best-characterized of the GHRPs, still unproven for its marketed use
Ipamorelin is among the better-characterized GH secretagogues, with published Phase I/II data on safety and pharmacokinetics. But 'well-characterized pharmacology' is not the same as 'proven anti-aging or body-composition benefit.' It was never approved for any indication, and the longevity/optimization claims made in the peptide market are not supported by outcome trials.
Replacement is not the same as a cycle
Any GH-raising dose in a healthy adult is supraphysiologic relative to their baseline. Ipamorelin is 'cleaner' on the cortisol/prolactin axes than GHRP-6, but the core unknown, the long-term consequence of chronically elevated GH/IGF-1, applies to it too.
What people get wrong
Often said'Ipamorelin has no side effects.'
ActuallyIt is cleaner on cortisol, prolactin, and appetite than older GHRPs, but it still raises GH/IGF-1 and carries GH-related metabolic risks; 'no side effects' overstates the case.
Who profits, and who pushes back
Nobody is named here yet, because we have not done that work on this entry. Read that as unfinished. Somebody almost certainly sells this, and somebody almost certainly disputes it. Assume both until we have checked.
Set against the alternatives
Compared with GHRP-6, ipamorelin produces far less hunger and negligible cortisol/prolactin; compared with GHRP-2, it is similarly selective but generally a lower peak GH stimulus. It is most often stacked with a GHRH analog like CJC-1295, which acts on a complementary receptor.
The market for this
What follows describes how this is bought and sold. It is not a buying guide and it is not an endorsement of any seller.
Compounded and gray-market; almost always co-sold with CJC-1295 as a 'GH stack.'
At a glance
- Amino acids
- 5 (pentapeptide)
- Target
- GHS-R1a (ghrelin receptor)
- Developer
- Novo Nordisk
- Selectivity
- No significant ACTH/cortisol/prolactin rise
What this entry does not yet cover
What follows is unfinished work on our side, not a finding about Ipamorelin. A short entry is not a safe entry.
- Cost and market. We have not documented what it sells for or who sells it.
- Supply chain. We have not mapped where it is made.
- Who uses it. We have not documented the user groups.
- What could change. No forward-looking summary yet.
- Children and teenagers. We have not checked what is known about younger people.
- Where we land. We have not taken a position on this yet.
Sources
The studies below are named and described, but not linked. You cannot open them from here and check our reading against them, which means this page is our summary of the literature rather than a document you can verify. Weigh it accordingly until the links exist.
The studies that matter
Raun et al., Eur J Endocrinol (Novo Nordisk)1998
Described ipamorelin as the first selective GH secretagogue; no ACTH/cortisol rise even at >200x the GH ED50