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Peptide entry · Growth

Ipamorelin

NNC 26-0161

Highest evidence

Human RCT

Studies recorded

4· 3 in humans

Legal status · US

Unapproved

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.

Jump to

Mechanism →Studies →Legal status →Risks & hygiene →

At a glance

★4studies 3in humans 2countries 1open question 1adverse event

01 Mechanism
★02 Evidence overview3
★03 Study landscape4
04 Where studies disagree1
05 Pharmacokinetics
06 Routes of administration1
★06d Safer use & risks
07 Adverse events1
07b Interactions
08 Risks & hygiene1
10 Anecdotal observations1
11 Legal status by country2
12 Reconstitution calculator
13 Related peptides
14 Study register4
15 Sources & methodology

Overview

What is it?

How is it meant to work? →

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 …

What do studies show? →

Human RCTNo efficacy on the primary endpoint 'time to GI function recovery' in the phase-2b trial on post-operative ileus

What do users report? →

In bodybuilding forums Ipamorelin is described as a 'gentler' alternative to GHRP-6 — same GH effect without hunger and cortisol rise.⚠ anecdotal – not scientific evidence

Mechanism of action

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

Human trial

Animal model

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.

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.

Pharmacokinetics

Theoretical concentration curve at a half-life of 2 h. Pure pharmacokinetic model — not a dosing recommendation.

Open in PK tool →

Start time: t₀ = 0h

Repeat interval: off (single dose)

Routes of administration in the literature

Which routes of administration the available studies describe — neutral reporting, not a usage guide.

Subcutaneous

Administered subcutaneously and intravenously in phase-1 studies.

06d

Safer use & risks

Risk notes for harm reduction — descriptive, not a usage or dosing guide.

Important — please read

This platform does NOT provide usage or dosing instructions. The points below describe risks and are meant to help avoid harm — they do not replace medical advice. Anyone who uses a substance should discuss it with a doctor.

There is no approved human use for this substance. What circulates online about amounts and frequency is self-experimentation without a safety net.

Online numbers are not a benchmark

Amounts from TikTok, YouTube and forums are mostly imitation rather than data — and are often wrongly derived from animal studies (µg/kg). Not a reliable benchmark for humans.

Sterility & infection risk

Injection solutions prepared or stored non-sterile carry an infection and abscess risk. Contamination is common with grey-market product.

Unknown product quality

Research-/grey-market product is not quality-tested: identity, purity and actual content are often unknown, and counterfeits occur.

Mind interactions

Combinations with medications or pre-existing conditions can carry risks (see the Interactions section). Clarify with a doctor beforehand.

Warning signs — seek medical help

With persistent pain, redness/swelling at the injection site, fever, shortness of breath, racing heart, chest pain or allergic reactions, seek medical help immediately.

A doctor, not a forum

Concrete questions about use and amount belong in a conversation with a doctor — not in a comment thread.

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.

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.

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.

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

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.

Substance (mg)Printed on the label

Solvent (mL)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.

Cofactors

⚠ Anecdotal (no evidence)

Glycine & arginine · Sleep & melatonin

Open cofactors guide →

These cofactors relate to the peptide class, not to a specific use. No recommendation, no dosing.

Study register

Animal modelControlled trial

Raun K. et al. · 1998

Ipamorelin, the first selective growth hormone secretagogue

PubMed ↗

Human trial

Gobburu JV. et al. · 1999

Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers

PubMed ↗

Human RCTRandomised controlled trial

Beck DE. et al. · 2014

Ipamorelin: a selective growth hormone secretagogue with potential to overcome opioid-induced bowel dysfunction

PubMed ↗

Human trial

Svensson J. et al. · 2000

Effects of seven days of administration of two doses of ipamorelin on growth hormone, IGF-I and IGFBP-3 in healthy men

PubMed ↗

Sources & method

Reviewed by

editor-placeholder

Last reviewed

2026-05-22

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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

Mechanism of action

Evidence at a glance

What the studies show

Where studies disagree

Is ipamorelin actually as selective as marketing suggests — i.e. without cortisol/prolactin rise?

Pharmacokinetics

Routes of administration in the literature

Safer use & risks

Known adverse events from studies

Interactions & combinations

Risks & hygiene aspects in the literature

WADA status

Anecdotal observations

Legal status by country

Reconstitution calculator

Cofactors

Related peptides

Study register

Ipamorelin, the first selective growth hormone secretagogue

Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers

Ipamorelin: a selective growth hormone secretagogue with potential to overcome opioid-induced bowel dysfunction

Effects of seven days of administration of two doses of ipamorelin on growth hormone, IGF-I and IGFBP-3 in healthy men

Sources & method

Get new studies on Ipamorelin

Mechanism of action

Evidence at a glance

What the studies show

Where studies disagree

Is ipamorelin actually as selective as marketing suggests — i.e. without cortisol/prolactin rise?

Pharmacokinetics

Routes of administration in the literature

Safer use & risks

Known adverse events from studies

Interactions & combinations

Risks & hygiene aspects in the literature

WADA status

Anecdotal observations

Legal status by country

Reconstitution calculator

Cofactors

Related peptides

Study register

Ipamorelin, the first selective growth hormone secretagogue

Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers

Ipamorelin: a selective growth hormone secretagogue with potential to overcome opioid-induced bowel dysfunction

Effects of seven days of administration of two doses of ipamorelin on growth hormone, IGF-I and IGFBP-3 in healthy men

Sources & method

Get new studies on Ipamorelin