Researchers from the University of Virginia have found a possible negative side effect of weight loss injection drugs on muscle mass. WMRA’s Ayse Pirge reports.
SIDDHARTHA ANGADI: These drugs, specifically, semaglutide and tirzepatide, they’ve really only been around, you know, in the public consciousness and widespread usage since about 2021. So, you know, we don’t have a lot of long-term data.
Siddhartha Angadi is an associate professor at the University of Virginia’s Department of Kinesiology. According to KFF, a health policy research nonprofit, about one in eight Americans has taken a GLP-1 drug, commonly known by brand names such as Ozempic or Wegovy. GLP-1 is a class of hormones that regulate blood sugar and appetite. Synthetic versions of the hormone, developed for the treatment of diabetes, are now being used for weight loss. Angadi says these drugs –
ANGADI: Appear to have a pretty good profile in terms of improving outcomes in patients with diabetes… helping out patients with heart failure. In fact, there are good data showing that they reduce the risk of something they call major adverse cardiovascular events.
But, he also says that people primarily lose weight from two components.
ANGADI: So, you lose weight from fat. And that’s where the majority of the weight loss is coming from with both of these drugs. And then, you lose a percentage of it from something called fat free mass.
‘Fat free mass’ is an umbrella term for substance in the body that is not fat. Angadi says that about 40 to 50% of fat free mass is muscle, and that that is where the concerns stem from.
Even though people lose some fat free mass when they lose weight without these drugs, the amount of loss is higher when they use these drugs.
Angadi also says that the weight people lose tends to come back if they stop using the drugs. He emphasizes the importance of maintaining one’s muscle health.
ANGADI: Muscular strength, and muscle quality is particularly important for maintaining that sort of… health span… And so, there are concerns that with such a large amount of fat free mass, of which a percentage, a significant percentage is muscle, this may have implications downstream for frailty.
Frailty, in clinical terms, is when a person is not able to perform daily activities for independent living. Angadi says people with frailty are at a much higher risk for adverse cardiovascular and health events.
Angadi says that, based on data from people taking an older form of GLP-1, exercise may help prevent muscle loss during weight loss. He says other studies that did not involve GLP-1s show that increasing protein intake prevented the loss of fat free mass.
