On Friday, the Food and Drug Administration approved a new injectable medication for treating obesity—one shown to help people lose a significant amount of weight in clinical trials when taken regularly. The drug, called Wegovy, may just signal a new era in obesity treatment.
Wegovy will be approved for chronic weight management in adults living with obesity or who are overweight with at least one health condition possibly related to their weight, such as type 2 diabetes, in conjunction with a reduced calorie diet and physical exercise. It’s taken as a once-a-week injection under the skin.
“Today’s approval offers adults with obesity or overweight a beneficial new treatment option to incorporate into a weight management program,” said John Sharretts, deputy director of the Division of Diabetes, Lipid Disorders, and Obesity in the FDA’s Center for Drug Evaluation and Research.
Wegovy’s active ingredient is semaglutide, an existing drug developed by Novo Nordisk used to manage type 2 diabetes. Semaglutide is a synthetic version of the human glucagon-like peptide-1 hormone (GLP-1), which helps regulate our sense of hunger and metabolism, among other things. In people with diabetes, the drug boosts their production of insulin, which then keeps their blood sugar in control. But research had also started to show that people taking semaglutide and other GLP-1 analogues tended to lose substantial weight, which prompted Novo Nordisk to test a higher dose (2.4 milligrams) for obesity treatment specifically.
The drug is the first since 2014 to be approved for obesity. But it seems to be much more effective than existing medications, almost rivaling the effectiveness seen with bariatric surgery and leading some experts to call it an “game changer.” In the largest 68-week-long trial of nondiabetic volunteers with obesity, those taking semaglutide lost, on average, 12.4% more of their initial body weight than people on placebo (both groups were counseled on how to maintain a healthy diet and exercise). Three other trials showed a similar pattern of improved weight loss, as well as the sustained maintenance of that weight loss, while on the drug.
Donna Ryan, an obesity researcher and professor emerita at the Pennington Biomedical Research Center in Louisana, told Gizmodo in an email that the results from these trials were more than enough to win its approval. “We have tons of experience on the safety side with the molecule, and the efficacy is beyond question,” said Ryan, who was not affiliated with the trials used to evaluate FDA approval. “With 42% of U.S. adults meeting BMI criteria for obesity, we need some safe and effective tools.”
Semaglutide, like any medication, does come with side effects. Common side effects have included nausea, diarrhea, vomiting, constipation, abdominal pain, headache, fatigue, and dyspepsia (indigestion), particularly in the first few weeks of taking the drug or adjusting to a new dose. The FDA will also require a boxed warning indicating the potential risk of thyroid C-cell tumors—a risk that has been seen in animal but not human testing so far. People at risk of certain thyroid cancers will be advised not to take it.
Wegovy’s approval isn’t just important for the drug itself, but for what it could mean for obesity treatment moving forward. There are other GLP-1 analogues being tested in clinical trials that are close to seeking approval, while research is ongoing into developing analogues of other gut hormones that similarly play a role in maintaining a healthy metabolism. Some early research has already shown that it may be possible to use these drugs alongside semaglutide to achieve even greater weight loss.
According to Ryan, it’s likely that Wegovy will only be the first of these newer treatments to reach the public. “The future is bright. The GLP-1s are the first targets—later we will tackle the other gut peptides and other signals from the gut brain axis,” she said.
While obesity has long been seen wrongly as an issue of will power or other personal failings, at least some obesity experts have argued that the effectiveness of newer drugs like semaglutide could change people’s conceptions of obesity and allow doctors to tackle it as the metabolic disorder that it is.
This article has been updated to include comments from Donna Ryan.