The U.S. Food and Drug Administration (FDA) approved a new weight-loss drug called Wegovy (semaglutide). It’s the first prescription drug for weight loss made available since 2014. The drug, a once-a-week injectable available by prescription, is intended to be used in adults who have a body mass index (BMI) of 30 kg/m2 or greater or a BMI of 27 kg/m2 or more and have at least one health condition—such as high blood pressure or diabetes—related to their weight. Wegovy should be used in conjunction with diet and exercise. Wegovy is manufactured by Novo Nordisk, a global healthcare company based in Denmark.

In an FDA press release, John Sharretts, MD, deputy director of the Division of Diabetes, Lipid Disorders, and Obesity in the FDA’s Center for Drug Evaluation and Research said, “Approval [of Wegovy] offers adults with obesity or [those who are] overweight a beneficial new treatment option to incorporate into a weight management program. FDA remains committed to facilitating the development and approval of additional safe and effective therapies for adults with obesity or [who are] overweight.”

How does Wegovy work?

Over 73% of Americans over the age of 20 are obese or overweight, according to the Centers for Disease Control and Prevention (CDC). That puts them at higher risk of serious diseases and conditions like diabetes, heart disease, stroke, certain cancers, and depression. Research shows that losing as little as 5% of your body weight can improve your health.

Wegovy (semaglutide 2.4 mg) is a glucagon-like peptide-1 (GLP-1) receptor agonist. In the body, GLP-1—a naturally-occurring hormone—helps to suppress appetite and delay the emptying of the stomach. Both of these effects help you eat less and feel fuller. Wegovy mimics GLP-1 (the manufacturer reports it is 94% similar to the real thing) and produces similar results. Wegovy doesn’t replace weight loss tools like diet and exercise—and instead should be used in conjunction with them.

How effective is Wegovy?

Wegovy was studied in four, 68-week trials. Researchers found that people who took Wegovy lost an average of 17% to 18% of their body weight compared to those who didn’t receive the drug. In trials conducted on those with diabetes, Wegovy helped people lose a more modest 6.2% of their body weight.

“Traditionally, our better weight-loss medications average 5% to 10% of weight loss,” says Charles “C.K.” Babcock, Pharm.D., a clinical associate professor at Marshall University School of Pharmacy. “This much weight loss has been shown to have a beneficial effect on health, yet it was often disappointing for many patients looking for cosmetic changes. But losing 17% of body weight is a substantial weight loss for many patients. And possibly more important for patients, the medication helped people continue to lose weight slowly for about 16 months. Slow loss is usually a healthier way to lose.”

Is Wegovy safe?

Wegovy is considered safe. The trials looked at more than 4,000 people (2,600 of whom received the drug). What’s more, semaglutide has been in use for a while. The FDA approved Ozempic (semaglutide) injection for diabetes treatment four years ago.

Certain people, however, shouldn’t use Wegovy. Wegovy has a boxed (black box) warning, which is the strongest warning required by the FDA. The warning states that people who have a history or family history of medullary thyroid cancer or people with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2) must not take Wegovy. This is because the drug causes thyroid C-cell tumors in rodents (the incidence has not been determined in humans).

Others who should not take Wegovy include those who are taking prescription, over-the-counter, or herbal drugs used for weight loss, and those who may be allergic to any of the ingredients in the drug. Other people, including those who have problems with their pancreas, gallbladder, or kidneys, should talk to their healthcare provider about whether they are good candidates for the drug.

The most common side effects of Wegovy are gastrointestinal in nature and can include:

Nausea
Diarrhea
Vomiting
Constipation
Abdominal pain
Flatulence
Indigestion
Gastroesophageal reflux disease (GERD)
Gastroenteritis

Wegovy can also cause:

Headache
Fatigue
Low blood sugar
Dizziness

Two major downsides to the medication are its delivery system (it’s an injectable) and cost.

“The company is working on an oral dose to treat weight loss, but it is not available yet,” Dr. Babcock says. “It must be noted that most health insurance companies do not cover weight-loss medication treatments—and the rumored cost for Wegovy is expected to be around $1,300 per month.”

Novo Nordisk plans on making Wegovy available in the U.S. at some point in June 2021.