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Science for Living: What to know about Ozempic and other weight loss drugs

Patients used to call the UMass Diabetes Center of Excellence with concerns about their blood sugar levels. Now, most calls are about problems obtaining a commonly prescribed class of drugs for managing type 2 diabetes that also helps them lose weight, according to endocrinologist Samir Malkani, MD, professor of medicine at UMass Chan Medical School and clinical chief of the Division of Endocrinology, Diabetes and Metabolism in the Department of Medicine. 

Drugs such as Ozempic (semaglutide) and Mounjaro (tirzepatide) that were designed to help lower blood glucose and reduce cardiovascular risks in type 2 diabetes are now in high demand among people wanting to lose weight, one effect of the drugs. Even at retail prices upwards of $1,000 a month, they’re flying off pharmacists’ shelves, according to Dr. Malkani. 

“A lot of people who are overweight struggle with eating behaviors,” said Malkani. “They want to eat, they’re stress eating, some binge eating, sometimes you just eat for comfort. When they take the drug, the desire goes away, so naturally they can eat less.” 

Here’s what to know about these weight-loss drugs: 

How do the drugs work? 

Products such as the diabetes drug Ozempic, which was rebranded as Wegovy and approved by the U.S. Food and Drug Administration for weight loss, use the drug semaglutide, while the diabetes drug Mounjaro, approved for weight loss under the name Zepbound, uses tirzepatide. Both are synthetic versions of the naturally occurring hormone GLP-1, said Malkani. 

“GLP-1 is made by our gut. When we eat a meal, GLP-1 enhances insulin production by our pancreas in response to the glucose that comes out of the food. But it also signals our satiety center in our brain to tell us to stop eating,” Malkani said. Synthetic versions of GLP-1 do the same thing but are much longer acting. 

The drugs are usually given by injection once a week. A pill form of Ozempic, called Rybelsus, is also available. But this has to be taken daily on an empty stomach. 

Malkani said the GLP-1 drugs have another potentially therapeutic effect: In some individuals they seem to cut down craving for alcohol and tobacco. 

Who can take the drugs? 

GLP-1 drugs are safe for most people to take, based on a physician’s prescription, according to Malkani. But insurance only covers the cost for certain conditions. People with type 2 diabetes would usually have the expense covered by their insurance. If someone is overweight, with a BMI of more than 26, and has a serious condition such as heart disease, it would typically be covered.  

If someone wants the drug for weight loss alone, Malkani said the threshold for insurance coverage is usually a BMI over 30, after a patient has tried a structured diet and exercise program. Some insurance plans require the patient to also have other health conditions associated with being overweight.  

What are the side effects? 

Malkani said doctors start prescribing a low dose to minimize side effects, and gradually increase dosage. Mild nausea is typical when starting treatments. Other common side effects are diarrhea, constipation, gallbladder problems and abdominal discomfort. 

“Some people do get side effects when they don’t eat and also forget to drink water,” said Malkani. “If you have borderline kidney function, you could get dehydrated.” 

Rare but more serious side effects include paralysis of the stomach and intestines and pancreatitis. There is a warning on the label about the increased risk of thyroid cancer, but this link is still uncertain.  

And although GLP-1 drugs have been touted as the solution to the stubborn weight gain that often accompanies menopause, Malkani cautioned that when people lose body fat, they also lose some muscle and bone. He encouraged postmenopausal women to get a baseline bone density evaluation before starting these drugs. 

Are GLP-1 drugs “forever drugs”? 

Once someone stops taking the drugs, cravings return and the weight will slowly come back, according to Malkani. A person may not need to take the same drug forever, though, because new and more effective formulations are being developed.  

“The new drugs they’re coming out with, they’re called small molecules. They’re not digested by the acid in the gut. So, in the future, people might just be able to take a pill,” he said. 

How is UMass Chan advancing what is known about diabetes/weight loss drugs? 

Malkani and his research team are collaborating with UMass Chan’s Program in Digital Medicine to analyze electronic health records of patients with heart disease who were prescribed GLP-1 drugs. “We’re trying to look at what the actual benefits are to them in terms of reduction of cardiac events, and how it affects total medical expenditures,” he said. 

Another research project aims to determine whether there are genetic factors that influence how people respond to the drugs. Malkani said, “There are some people who respond beautifully to these drugs, they lose 15 percent of their body weight. But there are some people who don’t.” 

This genetic database study is led by Nina Rosano, MD, assistant professor of medicine, and Amin  
Sabet, MD, assistant professor of medicine, specialists in endocrinology and diabetes. 

Science for Living features the perspectives of UMass Chan Medical School experts on the research behind health news headlines. If you have ideas for topics you’d like to see explored, please send them to