New US research suggests muscle loss with GLP-1s such as Ozempic may not be as high as previously thought.
Past studies found adults taking a GLP-1 medication can lose between 5-15 percent of their body weight within one year, while other research reported 25-39 percent of that weight loss was from muscle loss.
But a new study by scientists at the University of Utah, using a mouse model and reported in Cell Metabolism, found muscle loss from GLP-1 medications resulted in a lean muscle mass decrease of about 10 percent (less than some previous studies), and the decrease in lean muscle mass was not all from skeletal muscles, but from other body tissues, including the liver.
The researchers found that as the mice lost weight, some skeletal muscles did decrease, while other muscles stayed the same. They noted that the muscle mass decrease ‘is a return to baseline, as gaining fat is usually accompanied by a gain in skeletal muscle’. They also found some mice experienced a decrease in strength in skeletal muscles that stayed almost the same size.
Additionally, researchers found a good portion of the decrease in lean muscle mass did not come from skeletal muscles, but rather other tissues in the body, such as the liver, which they reported ‘reduced in size by almost half’.
Medicalnewstoday.com noted: ‘It is not uncommon for the liver to decrease in size during weight loss, which can help reduce a person’s risk for fatty liver disease.’
Senior author Dr Katsu Funai commented their data in mice suggests ‘things are not as straightforward as they might seem’.
