Ozempic Side Effects May Shrink Heart Muscles, Study Warns

Tests found Ozempic caused the hearts of mice to atrophy, leaving researchers unsure whether the loss of cardiac muscle mass may occur in humans as well.

The findings of a new study raises concerns that side effects of Ozempic, Wegovy and other popular weight loss and diabetes drugs may cause a loss of skeletal muscle mass in the heart, as well as other parts of the body, which could make it harder for individuals to exercise.

Ozempic (semaglutide) is part of a new generation of drugs known as glucagon-like peptide-1 receptor agonists (GLP-1 RAs), which was originally approved for the treatment of type 2 diabetes. However, since the medication is also effective at promoting weight loss, it has been widely used off-label as a diet drug, and the manufacturer Novo Nordisk introduced a weight loss version of semaglutide, under the brand name Wegovy.

Amid the increasing popularity of Ozempic and Wegovy over the past few years, similar medications have been introduced by Eli Lilly, under the brand names Mounjaro and Zepbound, and millions of Americans now use one of the GLP-1 RA treatments.

However, in a study released last month in the scientific journal JACC: Basic to Translational Science, Canadian researchers warn that the significant weight loss accompanying the use of drugs like Ozempic, may also lead to the loss of important muscle mass in other organs, including the heart.

Side Effects of Ozempic, Wegovy May Weaken Heart Muscles

Researchers from the University of Alberta conducted a series of experiments on mice, to evaluate the potential impact that Ozempic may have on heart muscles. If the findings translate to human users, they raise concerns that Ozempic side effects may not only result in cardiovascular muscle loss, but could also lead to an intolerance for exercise, which could have other long-term detrimental health effects.

For the study, researchers fed mice a high fat and sucrose diet for 10 weeks, causing weight gain, but not diabetes, to simulate the population of individuals using semaglutide for weight loss. The mice were then switched to a regular diet and given Ozempic.

Researchers found that the semaglutide diet treatments resulted in an 8.2% loss in skeletal muscle mass and lean body weight (BW) over the course of three weeks, as well as a reduced heart weight in the mice. This led researchers to conclude that Ozempic could lead not only to a decrease in body weight, but also a loss of muscle mass, which might weaken the heart, making exercise more difficult for already at-risk individuals.

“Although it is likely that the metabolic benefits from weight loss may outweigh modest sarcopenia, this loss of lean BW could potentially lead to exercise intolerance that may reduce the quality of life in individuals at risk for or with heart failure,” the researchers determined. “Given this, intense research efforts are ongoing to try to understand how GLP-1RAs induce loss of skeletal muscle mass. However, little attention has been given to the potential that other types of muscle, such as cardiac muscle, may also be lost in response to GLP-1RAs.”

The researchers emphasized that they are uncertain whether Ozempic or Wegovy use actually causes cardiac atrophy in humans specifically. However, they warned that this “has the potential to be detrimental in the long term.”

Ozempic Health Concerns

While GLP-1 RA drugs have been promoted as safe, with few long-term side effects, concerns about a number of potentially serious gastrointestinal problems have emerged, including the possibility of a form of stomach paralysis known as gastroparesis from Ozempic or other GLP-1 RA medications.

As a result of the drug makers’ failure to adequately warn about this and other risks, thousands of former users are now pursuing Ozempic lawsuits, Wegovy lawsuits and Mounjaro lawsuits, each raising similar allegations that the manufacturers placed a desire for increased profits above consumer safety by failing to research and disclose side effects users may experience before promoting the widespread use of the medications.

November 2024 Ozempic Lawsuit Update

Given common questions of fact and law raised in the claims, all federal GLP-1 RA lawsuits have been centralized as part of an MDL, or multidistrict litigation, where U.S. District Judge Karen S. Marston is overseeing coordinated discovery and pretrial proceedings.

The court is currently focusing early discovery and motions practice on a series of “cross cutting” issues that impact all claims, including an evaluation of general causation, pre-emption and whether specific gastroparesis testing is needed in the lawsuits.

Following rulings on early motions that may limit the size and scope of the litigation, it is expected that Judge Marston will schedule a series of early bellwether test trials, to help the parties gauge how juries may respond to expert testimony and evidence that will likely be repeated throughout hundreds of pending lawsuits.

While the outcomes of such early test trials are not binding on other claims, they are often critical to help the parties gauge how juries are likely to respond to certain evidence and testimony that will be repeated throughout the litigation, potentially facilitating Ozempic settlement negotiations that would avoid the need for each individual case to be set for trial in the future.