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What it is
A synthetic pentapeptide that acts at the growth-hormone secretagogue receptor — the same receptor ghrelin binds.
How it is proposed to work
Selective agonism at the GHS receptor triggers growth-hormone release. Its selectivity means it raises GH with substantially less effect on cortisol and prolactin than GHRP-2 or GHRP-6, which is the specific and legitimate reason it displaced them in community practice.
Approved medical uses
None. Ipamorelin has no approved human medical indication in the jurisdictions we track. Any use is outside an approved label.
Human research
Each entry states what the study found and, separately, what it cannot show.
- Randomised controlled trial2014n = 117
Phase 2 proof-of-concept trial in postoperative ileus after bowel resection
Finding. Negative on its key efficacy endpoint. In this multicentre, double-blind, placebo-controlled phase 2 proof-of-concept trial, adults undergoing small and large bowel resection by open or laparoscopic surgery received intravenous ipamorelin or placebo twice daily from postoperative day 1 to day 7 or hospital discharge; 117 patients were enrolled, of whom 114 composed the safety and modified intent-to-treat populations. Median time to first tolerated meal — the key endpoint, measured from first dose to tolerance of a standardised solid meal — was 25.3 hours with ipamorelin and 32.6 hours with placebo (p = 0.15), and the authors report no significant differences between ipamorelin and placebo in the key and secondary efficacy analyses. The authors conclude that ipamorelin was well tolerated; treatment-emergent adverse events of any kind occurred in 87.5% of the ipamorelin group and 94.8% of the placebo group.
Limitation. One proof-of-concept trial, which its own authors describe as small and as enrolling patients with a broad range of underlying conditions. The key endpoint was time from first dose to tolerating a standardised solid meal, in hospital inpatients after bowel resection; the abstract reports no growth-hormone or body-composition outcome, and it does not specify what the secondary efficacy analyses measured. The difference between the two median times was not statistically significant, so it should not be read as a trend in ipamorelin's favour.
Preclinical research
Animal and laboratory work. Useful for generating hypotheses; it cannot establish that something works in people.
- Animal1998
Selectivity profiling against comparator secretagogues
Finding. In primary rat pituitary cells ipamorelin released growth hormone with potency and efficacy similar to GHRP-6 (maximal effect 85±5% against 100% for GHRP-6), and profiling with GHRP and GHRH antagonists demonstrated that it stimulates GH release via a GHRP-like receptor. Specificity was then tested in conscious swine: none of the GH secretagogues tested affected FSH, LH, prolactin or TSH, but GHRP-6 and GHRP-2 both raised ACTH and cortisol, whereas ipamorelin did not release ACTH or cortisol at levels significantly different from those seen after GHRH stimulation — an absence the authors report as holding even at doses more than 200-fold above the level giving half-maximal GH release. The authors conclude it is the first GHRP-receptor agonist whose selectivity for GH release resembles that of GHRH.
Limitation. The work was conducted by Novo Nordisk, the compound's developer, in rat pituitary cells, anaesthetised rats and conscious swine. It characterises which hormones the molecule releases, not any clinical benefit in people; the prolactin result in particular does not separate ipamorelin from the comparators, since the abstract reports prolactin as unaffected by every secretagogue tested.
Potential safety concerns
- CautionInsufficient
Better selectivity than older GHRPs is not the same as an established safety profile. No long-term human dataset exists.
- WatchPreliminary
Ghrelin receptor agonism increases appetite, which works directly against a fat-loss goal.
Known interactions and contraindication considerations
- Not characterised in humans outside trial settings.
This list is not exhaustive and is not a substitute for a clinician reviewing your full medication history.
Regulatory status
Status is shown per jurisdiction and is accurate only as of the date stated. Where a compound is approved, the approval is bound to a specific formulation, manufacturer and indication — shown in the detail column.
| Jurisdiction | Standing | Detail |
|---|---|---|
United States FDA | Unapproved / investigational as of 1 Jun 2026 | No marketing authorisation. Sold as research material, which is not an approval of any kind. |
European Union EMA | Unapproved / investigational as of 1 Jun 2026 | No marketing authorisation. |
India CDSCO | Unapproved / investigational as of 1 Jun 2026 | A first-time synthetically manufactured peptide falls under the new-drug pathway. Central Licensing Authority permission is required before import or manufacture for sale or distribution. |
How it is being used
What the grey community actually runs, the reasoning they give, and our read on whether it follows from known biology. This is observation, not evidence, and not a recommendation.
Growth-hormone pulse and sleep quality
What is run
Pre-sleep and fasted, usually paired with a GHRH analogue. Frequently reported for subjective sleep improvement as much as for body composition.
Their mechanistic reasoning
That selective GHS-receptor agonism produces a growth-hormone pulse without the cortisol and prolactin rise of GHRP-2 or GHRP-6, and that a pulse timed to the natural overnight peak reinforces rather than disrupts normal physiology.
Reported in the community’s own terms. Not our position.
Stacked with
- CJC-1295 or another GHRH analogue—Separate receptors, expected to be synergistic on the pulse.
Regimen shape
- Dose
- figure withheld
- Scale
- Microgram-scale
- Route
- Subcutaneous injection
- Frequency
- Daily, sometimes split across the day
- Timing
- Pre-sleep, fasted
- Duration
- Multi-week blocks with breaks
Our read
The selectivity claim is genuinely well supported and is a real reason to prefer it over older GHRPs — this is a case where community practice moved in the direction the pharmacology points. The timing rationale is also sound. What remains unestablished is the endpoint: whether the resulting pulse produces body-composition change in a healthy trained adult. Sleep reports are plausible given growth hormone's relationship with slow-wave sleep, but subjective and uncontrolled.
What the community reports
The comparison is between how sure the community is and how much is actually known — evidence strength, not direction. A compound can have solid research that came out negative.
The preferred secretagogue in current community practice, and the reasoning behind that preference — selectivity — is genuinely sound. Reports are more often about sleep than about muscle.
Commonly reported as helping
- Deeper sleep, the dominant report
- Fewer side effects than older GHRPs, consistent with its selectivity
- Improved recovery
- Less hunger than GHRP-2 or GHRP-6
Also reported, when it goes wrong
- Some report no effect whatsoever
- Head rush or flushing shortly after injection
- Effects described as fading over a block, suggesting tolerance
Why these reports can mislead
Sleep quality is self-assessed, highly variable night to night, and strongly influenced by having just adopted a fixed bedtime routine. Almost nobody runs a baseline period before starting, so there is nothing to compare against.
Direct quotations are not published here yet. We will only carry verbatim reports once they are sourced, dated and checked — an unattributed quote is a testimonial, and testimonials are exactly what this section exists to replace.
Watch for, in this use specifically
- Ghrelin-receptor agonism increases appetite, which opposes a fat-loss goal.
- Selectivity is better than older GHRPs but is not the same as an established long-term safety profile.
Active clinical trials
No registered trials currently tracked for Ipamorelin.
What remains unknown
The questions that would change our assessment if they were answered.
- Does the GH pulse it produces change body composition in a healthy trained adult?
- Does the selectivity advantage persist with repeated long-term use?
References
- 1.Beck DE, Sweeney WB, McCarter MD, et al. Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients. Int J Colorectal Dis. 2014.PMID 25331030doi
- 2.Raun K, Hansen BS, Johansen NL, et al. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998.PMID 9849822doi
Editorial change history
When we change a grade or a regulatory note, we log it here rather than editing quietly.
Dossier created.
Spotted something wrong? Tell us — we publish corrections.