Ipamorelin is a small lab-made molecule, a chain of five of the building blocks that proteins are made from. It was designed from scratch at a Danish drug company, and the idea is that it nudges your body into releasing more of its own growth hormone, the messenger chemical the body uses for growth and repair. It is one of the very few things sold this way that has actually been given to people in proper hospital trials, though those trials were for a bowel problem after surgery, not for any of the reasons people buy it.
What it is supposed to do
It copies a natural hunger hormone called ghrelin, pressing the same switch in the body and prompting a release of growth hormone. In the one human study that watched this happen, growth hormone rose to a single peak around 40 minutes after the dose went into a vein, then faded away. Nobody has ever published how tightly it actually grips the switch it is supposed to work through, which is a basic measurement that is simply missing.
What people take it for
People take it hoping for more growth hormone, better sleep, fat loss, faster injury recovery and slower ageing. Not one of those has ever been tested in a human trial. The only two trials that exist were in patients whose bowels would not restart after surgery.
The dose question
What circulates
200 to 900 mcg per day, under the skin
What was studied
About 4.2 mg per day, into a vein
The published Helsinn trial, which missed its endpoint
Five to twenty one times smaller, and by a route nobody has studied in a person. The smaller number is smaller in a unit no one has converted.
Reported because it is what people use. Nothing here recommends any amount.
How long it lasts
About two hours. That figure comes from a single study in healthy men where it went into a vein. Nobody has measured how long it lasts in a person injecting it under the skin.
Route studied
Into a vein, in hospital
Route used
Under the skin, at home
How to check you have the right molecule
Two separate laboratory groups testing black market material found a different molecule in it: ipamorelin with one extra building block stuck on the front, called Gly-ipamorelin. Real ipamorelin weighs 711.9, and that extra piece adds 57.05, so the altered version weighs about 768.9. A certificate that states a weight anywhere in the high 760s has told on the product. On the machine reading that testing labs print, real ipamorelin shows a peak at 712.4 and the altered version shows 769.4; on methods that read the version of the molecule carrying two charges, real is 356.7 and altered is 385.2. Neither study was checking vials against their labels, so this says nothing about how common the problem is, only how to spot it.
People believe the headline selling point, that it raises growth hormone without raising stress hormones, is a human finding. It was measured in pigs, once, by the company that owned the molecule, and that same test also failed to detect a rise for an older compound that is known to raise those hormones in people, so the test itself proved nothing. In humans the number of measurements is zero.
What is known about harm
In the published trial, side effects overall were slightly lower on ipamorelin, but the Food and Drug Administration reviewing the same data in 2024 counted more low potassium, more sleeplessness and more high blood sugar in the ipamorelin group, and two patients in that group died after colon cancer surgery. The agency says plainly it is unclear whether those deaths had anything to do with the drug. The same agency searched nine databases and found no studies at all on poisoning, organ damage from repeated dosing, genetic damage, effects on fertility or unborn children, or cancer risk, and no stress hormone measurement in a human has ever been published for it.
Everything on this page is a summary. The citations, the studies and the reasoning live in the full entry.