Weight-loss drug Wegovy only works when you take it. Is it safe for the long term?

After losing 30 pounds with the anti-obesity drug Wegovy, Craig Hollingsworth says he plans on taking the medication for as long as he can — perhaps indefinitely.

He worries about regaining the weight if he stops — a known consequence for patients who halt the therapy — and has started to think of Wegovy as similar to the medications he takes long-term to control his high blood pressure and cholesterol.

Hollingsworth, 65, has experienced side effects including nausea, constipation and muscle weakness since starting Wegovy seven months ago, but says they’re worth the weight loss: he’s dropped from 245 pounds to 215. His goal weight is 200 pounds.

“It was easy, which was nice… it was almost like magic the way the pounds just fell away,” Hollingsworth, a technical writer who lives in Chapel Hill, North Carolina, tells TODAY.com about weight loss with Wegovy.

“I felt full faster so I didn’t eat as much… (and) I lost interest in the food. It was very easy to push things away.”

Hollingsworth says he doesn’t worry about how the drug could potentially affect his body if he takes it for years or decades. But his physician, Dr. Christopher McGowan, says the patients in his Cary, North Carolina, weight loss clinic often bring up a very legitimate concern: Is this really safe to take long-term?

When TODAY.com posed that question to doctors, some said they were “absolutely” comfortable prescribing Wegovy knowing a patient might take it for years, while others had “major concerns.”

How long to people need to take Wegovy?

Wegovy is in a class of drugs called GLP-1 receptor agonists and works by mimicking a natural hormone the body releases when a person eats food. This hormone, called glucagon-like peptide-1, targets areas of the brain that regulate appetite and food intake.

“The drug works by making people not hungry,” says Dr. Leigh Perreault, an endocrinologist at UCHealth in Denver, Colorado.

It was approved by the U.S. Food and Drug Administration in 2021 after its safety and efficacy were studied in four 16-month-long trials. Wegovy is meant for adults with obesity or those who are overweight and have complications such as such as high blood pressure. It has also been approved for the treatment of obesity in teens.

Participants who took the drug in the largest placebo-controlled trial lost an average of 12% of their body weight compared to those who received a placebo.

But patients have to keep injecting the medication under their skin once a week for it to work — otherwise, they will regain two-thirds of their prior weight loss, studies have shown.

Wegovy is the brand name for semaglutide, the same molecule found in Ozempic, the type 2 diabetes treatment, which some doctors have been prescribing off-label for weight loss. Both are made by the pharmaceutical giant Novo Nordisk, which says they are not interchangeable.

When asked if Wegovy was designed to be taken for years or decades and whether it’s safe to be taken for the long-term, the company didn’t answer directly, but emphasized that obesity should be treated as a chronic disease.

“Data from our clinical trials for Wegovy showed that, not unexpectedly, patients experience weight regain once they stop taking the medication,” the company says in a statement to TODAY.com.

“This supports the belief that obesity is a chronic disease that requires long-term management, much like high blood pressure or high cholesterol, for which most patients remain on therapy long term in order to continue to experience the benefits of their medications.”

The drug should be taken under the direction of a healthcare provider, together with meal planning and increased physical activity, the company adds.

What doctors say about using Wegovy long-term

When patients ask McGowan whether it’s safe to take the drug for years, he tells them there are no long-term studies on Wegovy. But he notes that GLP-1 receptor agonists have been used for more than a decade to treat Type 2 diabetes, “so we do have a very reassuring track record in general with these medications.”

Dr. William Yancy, medical director of the Duke Lifestyle and Weight Management Center, in Durham, North Carolina, says that after reviewing the research, he is comfortable prescribing Wegovy knowing that a patient might have to take it for years or decades.

“With the information that we have available currently, yes. But that information is accumulating over time,” Yancy tells TODAY.com. “We’re always accumulating knowledge and so that could change down the road, but at this point we have enough information to consider this as a long-term treatment.”

Patients should be prepared to take Wegovy for years since there isn’t “an antibiotic for weight,” Yancy notes. That doesn’t mean they have to take the medicine forever: sticking with lifestyle changes can allow them to come off it eventually, he adds.

Perreault, who serves on the scientific advisory board for Novo Nordisk, says she is “absolutely” comfortable prescribing Wegovy for the long-term.

She believes it makes people healthier based on studies that found that besides lowering blood sugar and body weight, it can protect the heart.

That doesn’t mean adverse events won’t happen in some patients, the doctors say. Common side effects include nausea, diarrhea, vomiting, stomach pain and other gastrointestinal issues, according to Novo Nordisk.

Possible serious side effects include pancreatitis, gallbladder problems, kidney problems and increased heart rate, among other issues, according to the manufacturer.

Wegovy and Ozempic carry the warning that semaglutide causes thyroid C-cell tumors in rodents, though it’s unknown whether that can happen in humans. People who have a personal or family history of medullary thyroid carcinoma or those who have multiple endocrine neoplasia type 2 syndrome should not use either drug, the warning for each medication states.

‘Everyone is looking for the quick fix’

Dr. Robert Lustig, a neuroendocrinologist and professor emeritus of pediatrics at the University of California, San Francisco, says he has “major, major concerns” about people potentially taking Wegovy for years or for life, especially teenagers.

“The greater the time on it — teens will be on it longer because they’re teens — the greater the risk for pancreatitis,” Lustig tells TODAY.com.

“If Wegovy has all of these side effects, then I predict that we’re going to end up seeing a whole lot more patients with significant side effects as administration ramps up.”

Pancreatitis is inflammation of the pancreas, a serious condition that can lead to complications, according to the National Library of Medicine. Acute pancreatitis has occurred in clinical trials of Wegovy, according to the prescribing information for the drug.

When asked to respond to Lustig’s comments, Novo Nordisk said the decision to prescribe an anti-obesity medication is at the discretion of the physician and the patient, or in the case of a young person, the patient and their parents.

“Studies have shown that adolescents with obesity are likely to have obesity in adulthood and are more likely to develop other weight-related complications like diabetes and cardiovascular diseases at a younger age,” the company said in a statement.

“Therefore, Novo Nordisk is committed to discovering, developing, and delivering innovative treatment options to improve the health of adolescents living with obesity.”

Adverse reactions with Wegovy in teens were similar to those reported in adults, though adolescents had greater incidences of gallbladder problems including gallstones, low blood pressure, rash and itching compared to adults taking the drug, the company said in a news release in December 2022.

Lustig believes obesity is a chronic symptom of a chronic metabolic dysfunction and says Wegovy makes people only “minimally” healthier. He’s not against the drug, but calls it a Band-Aid that’s not fixing the real problem.

“It’s like giving an aspirin to a patient with a brain tumor because they have a headache,” he says.

“I think that doctors are going to find this sort of the easy way out, and so they’re going to over-prescribe it… because everyone is looking for the quick fix.”

But the underlying chronic metabolic dysfunction is still there — as evidenced by the weigh re-gain when people stop taking Wegovy, Lustig points out. The fix is to change the food Americans eat so that they consume fewer refined carbohydrates and less sugar, which people don’t want to do, he adds.

Dr. Zhaoping Li, professor of medicine and chief of the division of clinical nutrition at the University of California, Los Angeles, says more long-term data is needed about Wegovy.

“I understand there is an argument that obesity is a chronic disease like hypertension, diabetes, and once you need to be on it, you should be on it for lifetime. But I don’t think the data is there really for that kind of statement. There is a potential, but we’re not there,” Li previously told TODAY.com.

“We need to be vigilant to monitor all our patients carefully.”

After drugs are approved, the FDA requires companies to do post-marketing surveillance to look for any side effects that didn’t show up in clinical trials, Perreault says.

“I understand why people are concerned and I always tell patients that they are ultimately in charge of their destiny…  they are the boss and so if at any time they want to stop (taking Wegovy), that’s fine, then they can,” she notes.

“But I think the fact that we actually finally have real tools to help people is amazing.”

Lustig tells people who want to lose weight to talk with a doctor or nutritionist about their particular cause of obesity, whether it’s hunger, reward, stress or a combination of those factors and then target those triggers. Each can be successfully managed, he says.

For people who are interested in Wegovy, Lustig advises them to proceed carefully — “without question with caution,” he says.