New study focuses on what happens if you stay on weight loss drug Wegovy for years

Amid the growing popularity of drugs used for weight loss like Ozempic, Wegovy, Mounjaro and Zepbound, one question has remained for users, what happens if they were to stay on the drug for years?

Now, a new study released earlier this month by Novo Nordisk, the maker of both Ozempic and Wegovy, is shedding light on what the long-term results look like for people on the weight loss medications.

"This is the longest study we've conducted so far of semaglutide for weight loss," Martin Holst Lange, Novo Nordisk's head of development, told Reuters.

Both Ozempic and Wegovy are part of a class of drugs called GLP-1 Receptor Agonists that help people produce insulin to lower the amount of sugar in their blood.

The drugs, made from a compound called semaglutide, work by slowing down movement of food through the stomach and curbing appetite, thereby causing weight loss.

The new study, presented this month at the European Congress on Obesity in Venice, Italy, focused solely on Wegovy, an injectable medication that is approved by the U.S. Food and Drug Administration for weight loss for people with obesity or who are overweight with a comorbidity like high blood pressure.

Ozempic is approved by the FDA to treat Type 2 diabetes, but some doctors prescribe the medication "off-label" for weight loss.

Here are four questions answered about the study's results, and what they mean for the future of weight loss.

1. Were people able to keep weight off by using Wegovy long-term?

Yes.

The study found that the majority of people on Wegovy lost weight, on average 10% of their body weight, in the first 15 months of using the medication and sustained their weight loss over four years with continued use of the drug.

"We see that once the majority of the weight loss is accrued, you don't go back and start to increase in weight if you stay on the drug," Lange told Reuters.

The results came from a clinical trial of over 17,000 people with preexisting heart disease as Novo Nordisk was testing Wegovy for its heart benefits in people who are overweight and obese.

2. Were there any side effects to using Wegovy long-term?

Around 17% of patients in the four-year timeline withdrew due to a side effect of taking Wegovy, mostly nausea, according to the company.

Among all medications used for weight loss, the most commonly reported side effects are nausea and constipation, but irreversible gallbladder and pancreatic disease is also reported.

Makers of these drugs recommend having a conversation about the side effect profile and personalized risks with a healthcare professional before starting.

3. Why would a person need to stay on a medication after weight loss?

ABC News chief medical correspondent Dr. Jennifer Ashton, a board-certified OBGYN and obesity medicine specialist, said that people should remember that obesity is a chronic condition.

"In the majority of cases, people who are on these GLP-1 medications and lose a significant amount of weight, can/will regain some or all of it when they discontinue it," Ashton said. "Why? It's because of the etiology, or what the causes are, of the conditions of overweight and obesity. It's not a temporary situation. It's a chronic condition."

Obesity is a medical condition that affects nearly 42% of people in the U.S., according to the U.S. Centers for Disease Control and Prevention.

Obesity has been associated with conditions like stroke and heart attack, hypertension, breathing difficulties, sleep apnea and an increased risk of early death.

4. What does maintenance look like on medications like Wegovy?

While long-term research has been done on GLP-1 medications and Type 2 diabetes, Ashton said there is still much research to be done on how the medications can be used long-term to help people maintain weight loss.

"What hasn't been even described or reported in the peer-reviewed medical literature is what does maintenance on these medications look like," Ashton said, adding, "That knowledge and awareness has to be there, that if you get to your goal weight, and you completely stop these medications, the vast majority, not all, but the vast majority of people will regain the weight that's lost."

Ashton said patients on a medication like Wegovy should work closely with their doctor determine what is best in their individual situation.

Generally, she said doctors may prescribe a lower dose of the medication to take in the long-term, or reduce the frequency of the dose.

"I think what you'll see is healthcare providers, doctors who are experienced in managing patients on these medications, when they [the patient] get to their goal weight, they'll say, 'Okay, let's drop your dose down first, and then we could try to space out the frequency of your dosing intervals,'" Ashton said. "What I've done, and I've spoken to other doctors in obesity medicine who are doing the exact same thing, is we'll say, 'Okay, instead of taking [an injectable dose] every week, let's try taking it every two weeks.'"

She continued, "Alternating one week on, one week off may be something that we start to see in the future become a more common, more official part of the maintenance regimen."