Ipamorelin
Ipamorelin Acetate
Also called NNC 26-0161, ipamorelina
A selective growth hormone releaser with two human studies
Ipamorelin tells the pituitary to release growth hormone by pressing the same switch the stomach uses when it is empty. In early pharmacology work it was selective: unlike older peptides in its family it largely left cortisol and prolactin alone. Its two human studies did not test muscle, fat or sleep, and it is not an approved medicine.
Presses the same switch the stomach uses to say it is empty, the one that also triggers a growth hormone release, but largely without the hunger. What set it apart in early pharmacology work is what it did not do: older peptides in its family also pushed up cortisol and prolactin, and this one mostly stopped at growth hormone. It is not an approved medicine.
- Half-life
- About 2 hours
- Status
- Not FDA-approved
Studied in people, and well studied in preclinical models
49 papers · 2 clinical trials
What Ipamorelin has been studied for
The reasons people look it up, roughly in order of how often, and what research exists for each. Interest in a use is not evidence that it works; the evidence is stated under each one.
Mechanism of Action
How Ipamorelin works
The stomach has a way of telling the brain it is empty. The hormone that does it is ghrelin, and the switch it presses does two things at once: it causes hunger, and it prompts a release of growth hormone.
Ipamorelin presses that switch, and this is the interesting part, without much of the hunger.
What selective actually means here
Earlier compounds in this family pressed the same switch but set off other things too. Cortisol went up, and so did prolactin, alongside the growth hormone.
Ipamorelin was the first one that largely stopped at growth hormone. That is what the word selective means on every page describing it.
It is often mentioned with CJC-1295 because the two act on different receptors on the same gland, and in physiology studies signals through both release more growth hormone than either alone. Nobody has tested the pair in people.
The gap worth knowing
Two human trials exist. Neither studied muscle, fat or sleep. One measured how fast it appears and clears; the other tested whether it could restart the bowel after abdominal surgery, and that development did not continue.
Everything about body composition is reasoned from what growth hormone does rather than shown for this compound. That is a chain of logic, not a result, and it is worth holding the distinction.
Ipamorelin side effects: what studies reported
In the early pharmacology work it raised growth hormone without the cortisol and prolactin rise seen with older compounds in this family. There is no large human trial to build a formal side-effect table from.
Reported outside trials
- A brief head rush or flushing
- Short-lived hunger, less than with the older ghrelin mimetics
- Mild puffiness
- Drowsiness
- Injection-site redness
Worth keeping an eye on
- Tingling hands if water retention builds, same mechanism as the other growth hormone peptides
- Headache
Source: Reports outside trials, plus the early pharmacology work. This is a summary of published findings, not a complete safety profile and not medical advice. Questions about Ipamorelin belong with a licensed clinician who knows your history.
Your Genetics & Ipamorelin
The genes involved in how Ipamorelin works
Ipamorelin works through the receptors these genes build, and the genes vary from person to person. Researchers have linked some of that variation to differences in how people respond. A DNA report tells you which versions you carry.
GHSR · ••
Builds the ghrelin receptor ipamorelin acts on. Variants have been studied for their association with appetite and body weight. No study has tested whether they change response to ipamorelin.
GHR · ••
The exon 3 deletion produces a shorter growth hormone receptor that some human studies, mostly of approved growth hormone in children, associated with greater sensitivity. It has not been studied with ipamorelin.
GHRL · ••
Variants in the ghrelin gene have been associated with differences in ghrelin levels and appetite in human studies. Ipamorelin acts on the same receptor as ghrelin; whether these variants change response to it is untested.
Somatostatin is the body's brake on growth hormone release. Variants in its gene are studied for their association with growth and metabolic traits. Any link to ipamorelin is untested.
The dots after each gene are where your own result goes. Your report fills them in with the two letters you carry at that position.
Which of these variants do you carry?
Your report reads the DNA file you already have against this research.
Often discussed alongside
Compounds that come up next to Ipamorelin in research and discussion. Each has its own page. None of this is a suggestion to combine them.
CJC-1295
the CJC-1295 and ipamorelin pairingModerate EvidenceCJC-1295 (Modified GRF 1-29)
A copy of the brain signal that tells the pituitary to release growth hormone, rewritten so the enzyme that normally destroys it in minutes cannot. The name covers two compounds that behave very differently: with DAC it keeps growth hormone up for days, without DAC it produces a short pulse. The human trial used the version with DAC.
4
Gene variants
30+
Studies
Sermorelin
acts on the GHRH receptor insteadModerate EvidenceSermorelin (GHRH 1-29)
A short copy of the message your brain sends telling the pituitary to release growth hormone. Because it works one step upstream, your body's own brake still applies and it can still say no, which is the safety argument for the whole class. It was an approved medicine, withdrawn for commercial reasons rather than safety, which is why it is still legal to compound when most peptides are not.
5
Gene variants
25+
Studies
Named combinations
A combination people search for by name, and what research exists on it.
Access
Access and legal status
Ipamorelin is not an FDA-approved drug. Products sold online as “research chemicals” are labelled not for human use, and FDA treats them as unapproved drugs when they are marketed for people. We don't link to any seller, and nothing on this page is a recommendation to obtain or use it.
Your DNA and Ipamorelin: see which of the variants studied alongside it you carry, and what that research does and does not show. Read my DNA, $99 →
Educational information only, not medical advice. Most peptides are not FDA-approved. Do not start, stop or change any medication or peptide because of this page; talk to a licensed clinician.
Worth knowing about Ipamorelin
Interactions and situations where there is a specific reason to be careful. Where the honest answer is that nobody has studied something, it says so and says what that leaves open.
- The evidence is for hormone release, not for the outcomes
- Trials and preclinical work show growth hormone rising. No trial has shown that ipamorelin builds muscle, reduces fat or improves sleep in humans. That gap is the most important thing to know about it.
- Not currently compoundable in the US
- Ipamorelin was not among the substances removed from FDA Category 2 in April 2026, and it is not on the 503A list. Pages saying a pharmacy can prepare it are wrong on the current position.
- Banned in sport at all times
- Growth hormone secretagogues are prohibited under WADA rules both in and out of competition.
The evidence behind Ipamorelin
Two human trials exist, and neither tested what people look it up for. One modelled how it behaves in the body; the other was a phase 2 trial for restarting the bowel after abdominal surgery. Development for that use did not continue. Everything about muscle, fat and ageing is extrapolated from preclinical studies plus what growth hormone itself is known to do, which is a chain of reasoning rather than a result.
The literature, counted
Counted in PubMed on 3 August 2026 for ipamorelin. Every figure links to the search that produced it, so you can re-run it. “Tagged human” is not the same as a human trial: that tag also covers work on human cells and reviews discussing people, which is why the trial count is given separately.
Studied in people
2 of 2The only kind that directly answers whether it works in humans.International Journal of Colorectal Disease · 2014
HumanProspective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus after partial bowel resection
Beck DE, Sweeney WB, McCarter MD
The main human trial, and worth knowing it was about getting the bowel moving again after surgery, not about muscle or ageing. A multicentre, double-blind, placebo-controlled study using intravenous infusions. Development for this indication did not proceed.
Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus after partial bowel resection: source for Ipamorelin (opens in a new tab)Phase 2
Read the paperPharmaceutical Research · 1999
HumanPharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers
Gobburu JV, Agersø H, Jusko WJ, Ynddal L
The only other human study: how quickly it appears and clears in healthy volunteers, and how the growth hormone response related to the amount given. It says nothing about long-term effects.
Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers: source for Ipamorelin (opens in a new tab)Read the paper
Preclinical studies
1 of 2Preclinical results do not automatically hold in people.Every source behind this page52 more
- The growth hormone secretagogue ipamorelin counteracts glucocorticoid-induced decrease in bone formation of adult ratsSvensson J, Lall S, Dickson SL, et al. · Growth Hormone & IGF Research · 2001Preclinical
- Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine PhysiciansMayfield CK, Bolia IK, Feingold CL, et al. · American Journal of Sports Medicine · 2026Review
Everything we cite for Ipamorelin, including preclinical work and early research. Each link goes to the source itself, so you can judge it rather than take our word for it.
Last updated · literature counts verified against PubMed on
Frequently Asked Questions
What has ipamorelin been studied for?
Its human research is two studies: one measuring how it behaves in the body and the growth hormone response in healthy volunteers, and a phase 2 trial for bowel recovery after abdominal surgery, which did not continue. It has not been tested for body composition, recovery, sleep or ageing, and it is not an approved medicine.
Why is ipamorelin mentioned with CJC-1295?
They act on two different receptors that both lead to growth hormone release: ipamorelin on the ghrelin receptor, CJC-1295 on the GHRH receptor. In physiology studies, signals through both release more growth hormone than either alone. No trial has tested the two together in people.
Do genes affect ipamorelin response?
No study has tested whether any genotype changes response to ipamorelin. GHSR, GHR, GHRL and SST build the receptors and hormones it works through, and some of their variants have been associated with appetite or growth traits in human studies. A DNA report can show which versions you carry and what that research does and does not show.
Watch
What clinicians and researchers say about Ipamorelin
1 hr 30 minPeptide Expert: What Do Peptides Actually Do? (EXPLAINED) - Dr Alex TatemThe Diary of a CEO · PodcastBPC-157TB-500MOTS-c
13 minDr. Explains Peptide Stacks Used for Muscle GrowthAshley Froese · EducatorSermorelinCJC-1295Tesamorelin
19 minLearn Peptides So Fast it's UNREALAshley Froese · EducatorGHK-CuKPVThymosin Alpha-1Learn more about Ipamorelin
12 guides mention Ipamorelin→how it works
Peptides for beginners: what they are, what is approved, and how to read the evidence (2026)
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how it works
In depthIpamorelin and sleep: what the research shows, and the body-clock genes that shape deep sleep
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comparisons
In depthIpamorelin vs CJC-1295: same goal, very different biology
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peptide guides
In depthPeptides studied for sleep: what the research on DSIP, Epithalon and ipamorelin measured
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safety
Are peptides legal in the US? 8 facts about FDA approval and compounding in 2026
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peptide guides
Peptides studied for muscle recovery and injury repair: 7 compounds sorted by human evidence
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Your DNA and Ipamorelin
What the research says about your variants.
The report
Which Ipamorelin variants do you carry?
Your report reads the DNA file you already have against the published research on 31 peptides, marker by marker, and says what that research does and does not show.
Read my DNA, $99