Scientific context only. Not medical advice, not a recommendation to use.
At a glance
Synthetic pentapeptide and selective growth-hormone secretagogue. Developed at Novo Nordisk in the 1990s as a pentapeptide GHRP successor; clinical development was discontinued after phase 2 (post-operative ileus).
Researched for
Post-operative ileus (phase 2)GH secretion in preclinical models
Official status
US: Unapproved
No FDA approval. Clinical development was discontinued after a negative phase 2. On the WADA prohibited list.
Ipamorelin is a selective agonist at the GH secretagogue receptor (GHSR-1a). Compared to GHRP-2 and GHRP-6 its selectivity for the growth-hormone axis is higher; ACTH, cortisol and prolactin are not significantly stimulated in clinical studies. This selectivity was the main reason for its development over older GHRPs.
02
Evidence at a glance
Reading note. The distribution shows on which evidence tier each observation sits. Strong colours mark stronger evidence — weaker tiers are deliberately visible, not hidden.
3 observations · 3 tiers
Human RCT
1
Human trial
1
Animal model
1
03
What the studies show
Human trial
Mensch
Raun K. et al. 1998
Selective GH stimulation without significant rise in ACTH/cortisol/prolactin documented in phase-1 studies in healthy volunteers
What does NOT follow: Data from pharmacokinetic studies; no phase-3 endpoint data for a clinical indication.
Human RCT
Mensch
No efficacy on the primary endpoint 'time to GI function recovery' in the phase-2b trial on post-operative ileus
What does NOT follow: This negative trial led to the end of clinical development; often omitted from forum discussions.
Animal model
Hund / Schwein
Increase of serum IGF-1 after subcutaneous administration reproduced in animal models
What does NOT follow: Consistent across multiple species; human clinical endpoints are limited.
04
Where studies disagree
Open question
Is ipamorelin actually as selective as marketing suggests — i.e. without cortisol/prolactin rise?
POSITION A
The Novo Nordisk original (Raun 1998) and several follow-ups describe ipamorelin as the 'first selective GH secretagogue' with minimal cortisol or prolactin response compared with GHRP-6 or GHRP-2.
POSITION B
Later human data (Svensson 2000, Gobburu 1999) showed at higher doses or chronic administration a measurable, albeit smaller, modulation of other pituitary axes. Selectivity is thus relative — not absolute.
CURRENT STATE · Ipamorelin is clearly more selective than GHRP-6 — but 'selective' does not mean 'completely isolated'. At the doses studied in research settings the advantage is real; the chronic-use window at lifestyle doses without medical supervision is not characterised in controlled studies.
05
Pharmacokinetics
Theoretical concentration curve at a half-life of 2 h. Pure pharmacokinetic model — not a dosing recommendation.
Which routes of administration the available studies describe — neutral reporting, not a usage guide.
Subcutaneous
Administered subcutaneously and intravenously in phase-1 studies.
07
Known adverse events from studies
Factual reporting of what studies observed. Not a safety statement for individual use.
Human trial
Milder symptoms than older GHRPs
Due to selectivity the typical GHRP companion effects (flush, hunger) are absent. Safety evaluation of long-term use outside the trial indication is entirely absent.
selten
07b
Interactions & combinations
Documented interactions and contraindications from studies, prescribing information and guidelines. Where no data exists, this is stated.
Reporting of risks, NOT a combination guide. The absence of an entry does not mean „safe to combine“ but „not sufficiently studied“.
No documented interactions recorded
We have not yet found robustly documented interactions for this peptide. This does NOT mean none exist — the data is limited.
08
Risks & hygiene aspects in the literature
What regulatory and scientific literature reports on risks, sterility and identity in non-pharmaceutical sources — descriptive, not a hygiene guide.
WADA status
Ipamorelin is on the WADA prohibited list under S2 as a GH secretagogue.
10
Anecdotal observations
Weakest evidence tier — not supported by studies
Reading note. This section gathers popular claims from communities and forums. They are explicitly marked as weakest-tier evidence. Unblinded self-reports are particularly prone to placebo, recall and confirmation biases.
Why no amounts or protocols are listed here. We deliberately show only WHAT communities report — not in what amount or how it is used. Anecdotal "doses" or "biohacker protocols" are neither verified nor standardised nor safe; publishing them would be a usage guide, which we do not provide on principle. Specific amounts belong in a conversation with a doctor, not in a forum.
In bodybuilding forums Ipamorelin is described as a 'gentler' alternative to GHRP-6 — same GH effect without hunger and cortisol rise.
widespread
Not supported by studies: The selectivity is well documented; however a direct clinical endpoint benefit for muscle building or body composition has not been established in studies. The only phase-2 trial had a different endpoint and was negative.
11
Legal status by country
Country
Status
Note
Checked
United States
Unapproved
No FDA approval. Clinical development was discontinued after a negative phase 2. On the WADA prohibited list.
2026-05-22
Germany
Unapproved
No EMA approval. Sale as a 'research chemical' is not legally covered; WADA-prohibited.
2026-05-22
12
Reconstitution calculator
Pure mg/mL maths — works like a calculator. Not a usage recommendation.
Peptides ship as a dry powder. Once dissolved in a liquid (reconstitution), this calculator answers a single question: how much substance is in one millilitre of solution afterwards?
1Enter the vial's substance amount (printed on the label).
2Enter how much solvent you add.
3Result = concentration in mg per mL.
Printed on the label
/
Liquid you add
=
2.50
mg / mL
5 mg in 2 mL gives 2.50 mg/mL — each millilitre contains 2.50 mg of substance.