Ipamorelin (NNC 26-0161)
Ipamorelin: What The Studies Actually Say
One published trial in patients. It found no statistically significant benefit, and two people on the drug died. No human study has tested the shots it is sold as, or measured muscle, fat or sleep. Most of the rest is rats, mice and pigs.
Updated 22 September 2026
Before you read this
This page explains what published studies found. That is all it is. It is not medical advice, and it is not instructions for using anything. Nothing here is meant to find, treat, cure or stop any illness. The compounds discussed on this site, retatrutide included, are not approved by the FDA for use in people. Research compounds are sold for laboratory use only — not for use in humans or animals. A study tells you what happened to the people in it. It does not tell you what would happen to you. What you do with what you read here is your responsibility, so talk to a doctor first. This page is published by Ascend Vials, which sells research compounds.
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Clinics sell ipamorelin for fat loss, muscle, sleep, anti-aging and injury recovery. FDA looked into it. None of those uses has been tested in a published human trial. FDA review, 2024
Here is what the research actually found, and what it never checked. Every claim has a link. Read them yourself.
The 30-second version
- Ipamorelin is a lab-made peptide that tells the pituitary gland to release growth hormone.
- In healthy men, one dose into a vein gave one growth hormone spike that faded within hours.
- The only published trial in patients found no statistically significant benefit. Two patients on ipamorelin died. FDA says it is unclear whether the drug played a part.
- A bigger trial of 320 patients finished in 2014. Its results were never made public.
- No published human study has tested it as a shot under the skin, the way it is sold, or measured muscle, fat or sleep.
- In mice it raised body fat — the opposite of the fat-loss pitch.
- It is not approved anywhere.
- Nothing sold online has been shown to match what the studies used. No study has checked.
What it is
Ipamorelin is a lab-made chain of five building blocks, developed by Novo Nordisk in the 1990s. Its makers called it "the first selective growth hormone secretagogue" — a drug that makes the pituitary gland release growth hormone. Eur J Endocrinol, 1998
It works by switching on the ghrelin receptor. That receptor is not only in the brain. FDA lists it in the stomach, gut, heart, liver, pancreas, fat and more. FDA review, 2024 Because it acts on the gut, a company called Helsinn later tested it as a hospital drug to get the gut moving after bowel surgery. Int J Colorectal Dis, 2014
FDA found med spas and wellness clinics offering it as shots, nasal sprays and by mouth, often mixed with CJC-1295. FDA review, 2024
The numbers, from the real studies
Only two published studies have tested what ipamorelin does in people.
Healthy men, one dose. Researchers gave healthy men a single 15-minute drip into a vein, at five dose levels, 8 men per level. Pharm Res, 1999 FDA says 2 men in each group got a fake drip. FDA review, 2024
Each dose gave one growth hormone spike. It peaked at about 40 minutes, then faded to almost nothing. The body cleared half the drug in about 2 hours. The study measured only ipamorelin and growth hormone — no IGF-1, no cortisol. Pharm Res, 1999 FDA notes the paper did not report any side effects. FDA review, 2024
Patients after bowel surgery. This is the only published trial in patients. It counted 114 adults who had part of their bowel removed. About half got ipamorelin through a drip for up to a week. The rest got a fake drip. Nobody knew who got what. The main question: how soon could people keep down a solid meal? Int J Colorectal Dis, 2014
That looks like 7 hours faster. But in the trial's own math, the gap was not big enough to rule out luck (p = 0.15). The other measures showed no significant differences either. Int J Colorectal Dis, 2014 FDA notes that one slice of patients, those who had open surgery, recovered faster on it. FDA review, 2024 A slice of a trial is a clue, not a result.
The bigger trial nobody saw. Helsinn also ran a second trial, with 320 patients. It finished in May 2014. No results were ever posted. Trial record On 22 September 2026, none of the 54 PubMed records for ipamorelin was a paper from it. PubMed search FDA's review quotes a 2020 paper saying development stopped because of "disappointing results." FDA review, 2024
The biggest ipamorelin trial ever run has no public result.
What was tested, and what was not
| What you hear | Tested in people? | What the research actually has |
|---|---|---|
| Raises growth hormone | Yes, one dose | One short spike, in healthy men |
| Raises IGF-1 | No | Rats: unchanged in one study, up in another |
| Burns fat | No | In mice, body fat went up |
| Builds muscle | No | Rats on steroid drugs kept stronger calf muscles |
| Stronger bones | No | Rats grew bigger bones, not denser ones |
| Better sleep | No | In the surgery trial, trouble sleeping was more common on it |
| No rise in stress hormones | No | Shown in pigs only |
| Faster gut recovery after surgery | Yes, 114 patients | No statistically significant benefit |
Read the whole table. Only two rows have people behind them, and neither shows a benefit you would notice in daily life.
Sources: Healthy men, 1999 · Rat bones, 1999 · Rats on steroids, 1999 · Mice, 2001 · Rat muscle, 2001 · Rat bones, 2000 · Pigs, 1998 · Surgery trial, 2014 · FDA review, 2024
FDA also found no human data on how the drug behaves, how safe it is, or whether it works when injected under the skin — the way it is sold. FDA review, 2024
"Selective" was shown in pigs
In pigs, two older peptides, GHRP-6 and GHRP-2, pushed up the stress hormones ACTH and cortisol. Ipamorelin did not raise them beyond what GHRH, the body's own growth hormone signal, did — even at more than 200 times the dose needed for growth hormone. Eur J Endocrinol, 1998
That is where the word "selective" comes from. It has never been shown in a person. The only study in healthy people measured growth hormone and nothing else. Pharm Res, 1999
What the animal studies found
- Fat went up, not down. In mice, it made fat pads heavier for body size — even in mice that cannot make growth hormone. In normal mice, growth hormone peptides including ipamorelin raised body fat and food intake. BBRC, 2001
- Bigger bones, not denser ones. Rats given it for 15 days grew their bones a little faster. Source, 1999 Over 12 weeks, rats' bones gained mineral only in step with their bigger bodies. The authors said the bones got larger, not denser. J Endocrinol, 2000
- Steroid damage. Rats on a strong steroid drug lost less weight when ipamorelin was added, and their IGF-1 rose. Source, 1999 In another study they kept stronger calf muscles. Source, 2001 It helped them hold on to protein too, but less well than growth hormone. Source, 2009
- The gut. In rats after belly surgery, it sped up the gut and helped the stomach empty. JPET, 2009 · J Exp Pharmacol, 2012 This is the idea that went on to patients — and missed.
- Wearing off. After 15 days of shots, the rats' growth hormone response to ipamorelin was slightly weaker. Source, 1999 That hints repeated use might blunt the effect. Nobody has checked in people.
This is animals. It is not proof of anything in people.
What to expect
The only side-effect numbers from any trial come from the bowel-surgery trial. Everyone in it had just had major surgery.
| Bowel surgery trial | Fake drip (58) | Ipamorelin (56) |
|---|---|---|
| Any side effect | 94.8% | 87.5% |
| Serious side effect | 15.5% | 17.9% |
| Low potassium | 3.4% | 12.5% |
| High blood sugar when leaving hospital | 8.6% | 14.3% |
| Trouble sleeping | 5.2% | 10.7% |
| Bowel connection leaked | 1.7% | 3.6% |
| Back in hospital within 30 days | 8.6% | 12.5% |
| Stopped because of side effects | 3 people | 3 people |
Sources: Int J Colorectal Dis, 2014 · FDA review, 2024
Look at the top row first. More people on the fake drip had a side effect. That is what a fake-drip group is for. The authors called the drug well tolerated. Int J Colorectal Dis, 2014 They said most side effects were mild to moderate and tied to the surgery or the illness. FDA review, 2024
Then look further down. Low potassium, high blood sugar and trouble sleeping were all more common on ipamorelin. FDA review, 2024
Two patients on ipamorelin died. Both had bowel surgery for colon cancer, and in both the new bowel connection leaked. FDA's account of the causes includes sepsis — a body-wide reaction to infection — kidney failure and a perforated ulcer. FDA says it is unclear whether the drug played a part. FDA review, 2024
FDA's safety list. In 2023, FDA put ipamorelin acetate on its list of substances that "may present significant safety risks." Its reasons include possible immune reactions from clumped or impure peptide, and serious side effects, including death, when it was given into a vein for gut problems. FDA risk list
The missing tests. FDA found no public animal studies of ipamorelin's toxicity — not short-term, not long-term, not for DNA damage, pregnancy or cancer. It says raising growth hormone could carry the risks on growth hormone labels, such as tumors and diabetes. That has not been shown for ipamorelin itself. FDA review, 2024
The CJC-1295 mix
CJC-1295 is a different molecule. It copies part of GHRH and latches onto albumin in the blood. JCEM, 2006 In healthy adults, the body took 5.8 to 8.1 days to clear half of it — against about 2 hours for ipamorelin. JCEM, 2006 · Pharm Res, 1999
The case for pairing them comes from a different peptide. In a 1990 study of 18 men, GHRP-6 and GHRH together released more growth hormone than the two added up. Bowers, 1990
No published human study has tested ipamorelin with CJC-1295. Not its safety, not its dose, not whether the two boost each other. PubMed search · ClinicalTrials.gov search The claim that the mix gives 3 to 5 times more growth hormone comes from a clinic's website, quoted in FDA's review. No study backs it. FDA review, 2024
FDA reports serious side effects linked to CJC-1295, including a faster heart rate and whole-body flushing reactions. FDA risk list
Is it approved?
No. Neither FDA nor we found any country where it is approved. FDA review, 2024
- United States: no FDA-approved drug contains it. In October 2024, FDA's advisers voted 0 yes, 12 no and 1 abstaining on each of its two forms, citing a lack of information on safety and on whether it works. FDA minutes It is still on FDA's safety-risk list, and by FDA's own review it meets none of the conditions a US pharmacy needs to make it. FDA review, 2024 · FDA risk list · FDA rules
- The rumor: you may read that it came off that list in April 2026. We found no FDA or Federal Register source for that. FDA's page, current as of April 22, 2026, still lists it. FDA risk list · Federal Register search
- Australia: prescription-only since 2015, along with CJC-1295 and other growth hormone peptides, partly because of misuse in sport and bodybuilding and unproven supplier claims. TGA, 2015 That is a legal category, not an approval.
- Everywhere else: FDA checked the European Medicines Agency and the European, Chinese, Indian and Japanese drug standards. No listing anywhere. FDA review, 2024
- Sport: banned at all times on the 2026 anti-doping list, along with CJC-1295. WADA, 2026
What is still unknown
Most of these gaps come from FDA's 2024 review. FDA review, 2024
- Any real result in people — muscle, fat, sleep, recovery, bone, aging, even IGF-1.
- Whether the two deaths were linked to the drug.
- Long-term safety. The longest published trial gave it for up to 7 days.
- Immune reactions, cancer risk, pregnancy and fertility. Never studied. The healthy-volunteer study enrolled only men.
- Even the head count. FDA says 48 people enrolled in the healthy-volunteer study. Five groups of 8 is 40.
What is in the bottle is not what was studied
One more thing.
Every human result on this page came from ipamorelin given into a vein by researchers — to healthy men in a drug study, or to patients in hospital. The one exception was a single nasal dose. Pharm Res, 1999 · Int J Colorectal Dis, 2014 · Drug Test Anal, 2015
FDA found that even the requests to let pharmacies make ipamorelin were missing data on impurities, clumping and bacterial toxins. FDA review, 2024 Powders seized by Danish customs turned out to be an altered version of ipamorelin, with an extra building block added — not ipamorelin itself. Source, 2019
No study has ever shown that a product sold online as "ipamorelin" is the same thing the studies used. Not the same purity. Not the same strength. Not even proof it is the same molecule.
So take every number on this page for what it is. It describes a drug given into a vein by researchers, once or for up to a week. It describes nothing else.
How to check a number yourself
You are going to see more claims about ipamorelin. In a reel. In a comment. On somebody's store page.
Here is how to tell a real one from a marketing one. Five questions. About ten seconds each.
1. Is there a link to a study?
A real number comes from a paper you can open. No link means it is a claim, not a result. Search the name on pubmed.gov yourself. If nothing comes back, nothing was published.
2. People, or animals?
The "selective" label is from pigs. The bone results are from rats. The fat result from mice points the wrong way for the ads. Ask which animal before you ask anything else.
3. Did it measure the thing being claimed?
The one study in healthy people measured growth hormone in blood, for a few hours. A claim about muscle, fat or sleep needs a study that measured muscle, fat or sleep. None has been published.
4. Was it given the way it is sold?
Every published human result came from dosing into a vein, apart from one nasal dose. The product is sold as shots under the skin. Nobody has published what happens that way.
5. Where are the results?
A finished trial should have a result. Open its record on clinicaltrials.gov and look for posted results. The biggest ipamorelin trial finished in 2014. Nothing was posted. A result only the company has seen is not one you can check.
Now run those five on this page
Every number above links to its paper. The table says which claims were tested in people and which only in animals. The missing trial is named, with a link.
The claims in the ads — fat loss, muscle, sleep, recovery, anti-aging — have no link, because no published study in people has measured them.
That is the whole difference: a number you can check, and a number you are asked to believe.
This page has a date on it, near the top. If the missing trial's results come out, or a new human study is published, this page changes.
Read the studies yourself
- Bowel surgery trial, Int J Colorectal Dis 2014 — the only published trial in patients · Trial record
- Healthy men, one dose, Pharm Res 1999
- The 320-patient trial record — no results posted
- Nasal anti-doping study, Drug Test Anal 2015
- FDA review for the October 2024 advisory meeting — the source for most safety and status facts
- FDA advisory meeting minutes — the votes
- FDA safety-risk list · FDA pharmacy rules · Federal Register search
- Pigs and rats, Eur J Endocrinol 1998
- Rat bones: Growth Horm IGF Res 1999 · J Endocrinol 2000
- Mouse body fat, BBRC 2001
- Steroid-treated rats: 1999 · 2001 · 2009
- Rat gut after surgery: JPET 2009 · J Exp Pharmacol 2012
- CJC-1295: JCEM 2006 · JCEM 2006, overnight study · GHRP-6 plus GHRH, 1990
- CJC-1295 with ipamorelin: PubMed search · ClinicalTrials.gov search
- Danish customs powders, 2019
- Australia decision, TGA 2015 · WADA Prohibited List
- All PubMed records for ipamorelin
Everything above describes what studies gave to enrolled volunteers and patients, or to lab animals. This is not advice, a plan, or instructions. Ipamorelin is not an approved medicine in any country FDA or we checked. Research compounds are not for human or animal use.