As many of us know, keeping weight in check can be hard. National data reflect that reality. Rates of overweight and obesity in the U.S. have steadily climbed since the early 1980s.
The impact on health and well-being is significant. Weight gain and obesity increase the risk of 13 cancers, diabetes, stroke, arthritis, mobility problems and many other serious conditions.
So, the recent rise of GLP-1 medications for weight loss has become a promising development.
Officially known as glucagon-like peptide-1 receptor agonists, GLP-1 drugs were first approved to treat type 2 diabetes — and later for weight management. The most commonly used GLP-1 drugs are semaglutide, sold as Ozempic or Wegovy, and tirzepatide (a dual GIP/GLP-1 receptor agonist), sold as Zepbound. They’re usually given as a once-a-week self-injection, but a semaglutide pill recently became available.
“GLP-1 receptor agonists are based on hormones that are made naturally by the body when we eat,” said Dr. Cynthia Herrick, a professor in the Division of Endocrinology, Metabolism and Lipid Research at WashU Medicine. “They slow the movement of food through the gut and have a complex effect on signals of fullness in the brain.”
In response, people eat less — and lose weight. Those using the most common once-a-week GLP-1 drugs have been shown in studies to lose about 15% to 20% of their body weight.
In addition to weight loss, studies have found a range of health benefits, which can vary depending on the specific drug. Herrick said they can help treat type 2 diabetes, prevent future heart attacks and strokes in people who have had them, and lessen certain liver and kidney conditions.
“The newest once-weekly drug, tirzepatide, has also been approved to treat moderate to severe sleep apnea,” Herrick added.
As with any medication, there can be downsides. Serious side effects are rare but can include gallstones, an inflamed pancreas and problems with food moving through the digestive system. There is also some concern that GLP-1 drugs may increase the risk of thyroid cancer, but so far studies have not shown this.
More common side effects include nausea, occasional vomiting, bloating, mild diarrhea and constipation. To help minimize these, people are started on low doses, which are then increased monthly, Herrick said.
Since research on these drugs is still relatively new, it will take time before we have more complete information about their long-term safety and benefits.
In addition to diabetes, GLP-1 drugs are most commonly prescribed for weight loss for people with a body mass index, or BMI, of 30 or higher, or a BMI of 27 or higher who also have a related condition, such as high blood pressure or unhealthy blood cholesterol. Someone who is 5 feet 6 inches tall and weighs 186 pounds would have a BMI of 30, for example.
Insurance coverage for GLP-1 drugs can vary. Most plans cover a GLP-1 drug to treat diabetes, but they are less commonly covered for weight loss or other approved conditions. Even with insurance, monthly costs on some plans can exceed $1,000 until people meet their deductibles.
Some options, though, can help. “There are now direct-to-consumer programs from the pharmaceutical companies that can lower the cost to $150 to $450 per month, depending on the medication and dose,” Herrick said.
Since people on GLP-1 therapy will likely take it long term, affordable access is especially important. “I tell people to think of these the way we think of blood pressure and cholesterol medicines,” Herrick said. “These work to reduce heart disease risk, but only when taking the medications. When people stop them, weight can increase.”
Maintaining physical activity and healthy eating remains important while taking GLP-1 drugs and is a key recommendation from many organizations. It can boost the benefits of medication, improve quality of life and help maintain weight loss.
“I’ve had patients note that they no longer have a taste for sugar-sweetened beverages or alcohol after starting these medications. They find it easier to limit processed food intake and to control portions,” she said. “And as people begin to lose weight, they often find regular physical activity easier to do.”
Interest in GLP-1 drugs is growing. A recent KFF survey found that as many as 12% of people in the U.S. already take one, and that number is likely to increase. While we still have much to learn about their long-term risks and benefits, early evidence shows real potential to improve health and well-being.
Dr. Graham A. Colditz, an internationally recognized leader in cancer prevention, leads prevention research at Siteman Cancer Center at Barnes-Jewish Hospital and WashU Medicine in St. Louis.