What’s the Difference Between Ozempic, Wegovy, Mounjaro, and Zepbound?

A female customer talking with a pharmacist.
While prescription drugs like Ozempic, Wegovy, Mounjaro, and Zepbound may be growing in popularity due to their ability to similarly aid with weight loss, they all have nuanced and important distinctions from one another. nortonrsx/Getty Images
  • Ozempic” has become a catch-all term for a class of weight loss drugs that also includes Wegovy, Mounjaro, and Zepbound, but the drugs have nuanced, important distinctions.
  • New research suggests tirzepatide drugs (Mounjaro and Zepbound) may lead to greater weight loss.
  • Experts say it’s important to speak with your primary care physician before taking any of these medications.

“Ozempic is like Vaseline,” says Dr. Mitch Roslin, the director of bariatric medicine at Northern Westchester Hospital in Westchester County, N.Y.

Roslin is referring to the idea that Ozempic has become the go-to name for a class of injectable weight loss drugs used to treat diabetes, obesity, and some individuals who are living with overweight.

The other drugs often referred to as “Ozempic” are Wegovy, Mounjaro, and Zepbound, the third of which was approved by the FDA for weight loss on Nov. 8. 

“Ozempic has simply become synonymous with the GLP-1 medications due to its ubiquitous coverage in the media,” says Dr. Christopher McGowan, a gastroenterologist, obesity medicine specialist, and the founder of True You Weight Loss.

Except the drugs have differences. In fact, Ozempic isn’t FDA-approved for weight loss, only diabetes.

Understanding the similarities and differences can help patients make informed decisions about their healthcare and, together with their primary care physician, determine which weight loss drug might be best for you.

Ozempic and Wegovy (Semaglutide): What to know

Ozempic was approved by the FDA for type 2 diabetes at 0.5 mg and 1 mg doses in 2017 and at a 2 mg dose in 2022. The FDA approved Wegovy at larger, once-weekly 2.4 mg injectable doses in 2022. Unlike Ozempic, Wegovy was approved for individuals with:

  • A body mass index (BMI) of 30 kg/m2 or higher (obesity)
  • A BMI of 27 kg/m2 or higher (overweight) with a weight-related condition like high blood pressure

Both drugs employ the same mechanism.

“The medications work by stimulating the GLP-1 receptor, which makes the patient feel less hungry and also slows the emptying of the stomach,” says Dr. Mir Ali, a bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, Calif.

Semaglutide also affects the brain.

“In addition, semaglutide targets areas of the brain, such as the hypothalamus, that control appetite and influence eating decisions, which may further assist with weight loss,” says Dr. Katherine H. Saunders, DABOM, an obesity expert, co-founder of Intellihealth, and a clinical assistant professor of medicine at Weill Cornell Medicine

Ali says that patients should plan to be on either version of semaglutide long-term.

A trial published in 2022 suggested that people who ceased using semaglutide at Wegovy’s 2.4 mg doses regained two-thirds of lost weight within a year.

Though Ozempic and Wegovy are brand names for the same drug (semaglutide), they aren’t quite the same. Administration tools are slightly different.

“Wegovy’s injection is delivered via a single-use, disposable pen, in contrast to the multi-use pens for Ozempic,” McGowan says.

Perhaps more notably, Wegovy is delivered at a higher dose.

Research from a 68-week trial of almost 2,000 people indicated that people taking the 2.4 mg dose of Wegovy lost about 15% of their body weight. Can the suggested benefits — and others linked with doses of semaglutide higher than what Ozempic is approved for — be applied to Ozempic?

While experts can’t say for sure, they believe the benefits are likely applicable.

Saunders explains that these benefits include:

  • Lower blood sugar
  • Reduced risk of heart failure
  • Average weight loss of about 15%
  • Reduced appetite and cravings
  • Reduced interest in cravings

Preliminary research from a new study that has not been peer-reviewed but was presented at the European Associated for the Study of Diabetes indicated that once-weekly doses of Ozempic and Wegovy were effective in managing weight and blood sugar in individuals with type 2 diabetes for up to three years.

In October, Novo Nordsick, which manufactures Wegovy and Ozempic, said it was halting a trial studying Ozempic’s effectiveness at treating kidney failure in patients with diabetes at the recommendation of independent monitors, who said the drug would clearly succeed. 

Novo Nordisk released results from a SELECT cardiovascular outcomes double-blinded trial that it commissioned in August of 2023. It included more than 17,000 adults ages 45 or older who were living with overweight or obesity and had established cardiovascular disease but no history of diabetes.

Results indicated that patients significantly reduced their risk of major adverse cardiovascular events (MACE) like heart attacks for up to five years.

However, the drugs have side effects. McGowan says these side effects include:

Ozempic and Wegovy both carry warnings for the potential for thyroid tumors, including cancer. In October of 2023, the European Medicines Agency (EMA) said it did not see an increased risk for thyroid cancer in GLP-1 drugs after monitoring side effects since April.

Mounjaro and Zepbound (Tirzepatide): What to know

Mounjaro and Zepbound are manufactured by Eli Lily, unlike Ozempic and Wegovy, which fall under the Novo Nordisk umbrella. Like Ozempic and Wegovy, one drug is approved for Type 2 Diabetes (Mounjaro in 2022), and the other, Zepbound, is approved for weight loss as of Nov. 8, 2023.

As with Wegovy, individuals qualify to take Zepbound if they meet the following criteria:

  • A body mass index (BMI) of 30 kg/m2 or higher (obesity)
  • A BMI of 27 kg/m2 or higher (overweight) with a weight-related condition like high cholesterol or diabetes.

Unlike Ozempic and Wegovy, there’s essentially no difference between Mounjaro and Zepbound other than the name.

“It’s like being called Susie at home and Susan at work,” Roslin says.

However, tirzepatide and semaglutide are not the same.

“Mounjaro is a glucose-dependent insulinotropic polypeptide (GIP) receptor and GLP-1 receptor agonist,” Saunders says. “GIP and GLP-1 are satiety hormones that are naturally produced by the intestine.

Mounjaro mimics these hormones, which leads to feeling full sooner after eating and remaining full longer. Mounjaro also slows down digestion, which can help with portion control and hunger.”

It sounds similar to Ozempic and Wegovy — and it is. But the dual-hormone mechanism makes it distinct. 

“Due to its dual-hormone mechanism, Mounjaro appears to provide a greater improvement in glucose control than Ozempic, though this has not been studied in head-to-head trials,” McGowan says.

Research conducted by Eli Lily from a pair of trials, SURMOUNT-3 and SURMOUNT-4, indicated that individuals taking tirzepatide lost 26.6% of their body weight over an 84-week period, which is more than the 15% people lost using Wegovy in a shorter 68-week span.

It can also be taken at a higher weekly dose.

“Mounjaro is taken as a once-weekly, subcutaneous injection via a single-use, disposable pen injector,” McGowan says. “The starting dose is 2.5mg, increasing by 2.5 mg every four weeks until a final dose of 15 mg, or the maximum tolerated dose, is reached.”

Additionally, Saunders says that, while the benefits and side effects are similar, tirzepatide appears to be better tolerated.

More significant weight loss and the potential for fewer side effects may make tirzepatide sound like a better option at face value. But Roslin says it’s too soon to tell, mainly because trial data doesn’t typically translate as well to the general population.

“Nothing will do as well in real life as it does in clinical trials,” Roslin says. “People who go into clinical trials are motivated…This is just the beginning of learning about these drugs.”

Ozempic, Wegovy, Mounjaro, or Zepbound: Which is best for weight loss?

Ali suggests speaking with your primary care physician first. They can refer you to a team, such as an obesity medicine specialist and dietician, who can help. 

The choice may be out of your hands — for instance, patients without diabetes don’t qualify for on-label use of Ozempic or Mounjaro.

Finally, insurance may or may not cover certain drugs, and accessibility is still an issue, Ali says. In short, the decision may be made for you due to your qualifications, budget, and insurance.

It’s worth noting that another similarity between semaglutide and tirzepatide is that the trials indicated that the weight loss benefits occurred in conjunction with other lifestyle changes, like diet and exercise.

“These medications are a tool to help with weight loss, but are most effective when combined with long-term changes to diet and lifestyle,” Ali says.

Roslin says that one of the most important similarities is that these drugs — and the others expected to come after them — offer hope for better patient health outcomes.

“With these drugs, we have effective therapies for obesity,” he says. 

Takeaway

While “Ozempic” has become a catch-all term for GLP-1 drugs that can aid with weight loss that include medications like Wegovy, Mounjaro, and Zepbound, the drugs all have nuanced and important distinctions.

Ozempic is not approved for weight loss. Another drug, Mounjaro, isn’t either. These two are approved for diabetes.

Wegovy and Zepbound are approved for people who are living with obesity or overweight with at least one other weight-related condition like high blood pressure.

Trial data indicates that people taking Mounjaro lost more weight, but experts share it’s too soon to say.

Side effects of all of the drugs primarily include GI upset. Speak with your doctor and see what — if any — of the drugs your insurance will cover if you meet the criteria to take them on-label.

Experts say these insights will help you make the best decision for you.

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