Hunger, body fat, and the number on your scale
Does Ipamorelin Cause Weight Gain? It did in animals
Mice added fat and became heavier. People haven't had the same test, so human fat-loss claims remain unproved.
Ipamorelin raised body weight and fat in mice
More hunger or a higher number on the scale may worry you. Mice given ipamorelin gained both body weight and fat.
Two weeks of injections placed beneath their skin raised body weight about 15%. Stored body fat rose as well [7].
The change also occurred in mice unable to make growth hormone. Another part of the drug's action must have helped cause the gain.
Your body uses ghrelin to bring on hunger, and ipamorelin acts like it [8]. The animal results point toward more eating and more body fat.
No human study has measured muscle and fat after ipamorelin. The only patient trial watched bowel function return after an operation, so it asked a very different question [3].
A promise of fat loss therefore goes beyond the proof. Mouse results can't tell you how your weight would change.
Two animal studies moved body weight upward
In 2001, one study compared two groups of mice. One group made growth hormone, while the other couldn't.
Both groups received ipamorelin beneath the skin twice daily. After two weeks, each group gained about 15% in body weight.
Stored body fat also rose in each group [7]. Growth hormone therefore wasn't needed for all the fat gain.
The drug's link with hunger may have played a part. That still gives no sure answer about your own weight.
In 2024, ferrets on cancer treatment received 1 to 3 milligrams per kilogram of ferret weight. Ipamorelin reduced their weight loss by about 24% [5].
The drug kept body weight from falling in sick animals. It didn't show weight loss or fat loss.
The hunger effect can lead animals to eat more
Ipamorelin acts like ghrelin, the hormone that makes you hungry. Drugs with that action made rat brains bring on hunger.
The rats then ate more [8]. If hunger rises, you may eat more, though this test used rats rather than people.
Animal tests also found more stored body fat [7]. That result gives you another reason to be cautious about weight claims.
Early tests found that cortisol and prolactin stayed level [1]. That narrow hormone result doesn't remove the possible hunger effect.
A leaner look in personal reports is not proof
Some people taking ipamorelin on their own say they look leaner. People gave these reports on their own; no controlled study has shown that ipamorelin caused the change.
People tend to notice the change from the fifth week through the twelfth. They describe it as slow and small.
Diet and exercise also changed in many of these reports. Either one could fully explain a leaner look.
Growth hormone can help the body use stored fat for energy. Human tests haven't measured that result with ipamorelin.
One rat test found more bone growth as the amount rose [4]. That test was about rat bones, so it can't support a human fat-loss claim.
No human study has shown weight loss from Ipamorelin
Animal studies found added body weight, more hunger, and more fat [7][8]. Ferrets on cancer treatment also lost less body weight [5].
No controlled human study has measured muscle and fat after ipamorelin. The only patient trial watched bowel recovery but failed to reach its main goal [3].
The studies don't show that ipamorelin causes fat loss for you. They give you more reason to watch for hunger.
Reports of looking leaner began with personal accounts, not trials. The Ipamorelin research page helps you follow the animal work.