What's the difference between Ozempic and Zepbound? Our comprehensive guide to weight-loss drugs

Photo of a person injecting a weight-loss drug in the thigh.
New weight-loss drugs have marked "the start of a new era" in the treatment of excess weight and obesity, say experts. (Getty Images)

Drugs like Ozempic and Wegovy have exploded in popularity and have practically become household names. Now, there's a new one to add to the list: Zepbound.

The Food and Drug Administration recently approved Zepbound for the treatment of excess weight and obesity, giving people one more tool to lose weight. "People have a lot more options," Dr. Mir Ali, a bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, Calif., tells Yahoo Life. "The medications that were once available for weight loss were not nearly as effective as the newer medications we have now."

Dr. Rashika Bansal, assistant professor in the division of endocrinology at Rutgers Robert Wood Johnson Medical School, tells Yahoo Life that the new weight-loss medications are "the start of a new era," adding that it's a "very exciting time" for weight-loss treatments.

Dr. Steven Batash, a gastroenterologist and leading physician at Batash Endoscopic Weight Loss Center, agrees. "We are at a turning point in our capability to treat obesity medically," he tells Yahoo Life.

But for all of the buzz swirling around these medications, it's not always clear how they work or what the difference is between Ozempic and Wegovy, for example. With that in mind, here's a breakdown of the basics of weight-loss drug terms you may have heard.


Semaglutide is a peptide that helps treat type 2 diabetes. It causes an increase in your body's insulin, which is a hormone that helps escort blood sugar to your cells, where it's used for energy, decreasing your blood sugar in the process, explains Ali. At the same time, it slows digestion, which makes you feel fuller longer, he says. Because of that, semaglutide can often lead to weight loss too. Semaglutide is the active ingredient found in Novo Nordisk's weight-loss drug Wegovy and type 2 diabetes medication Ozempic.


Tirzepatide is a medication that's used to treat type 2 diabetes and for weight loss, and it's the first medication in a drug class known as GIP/GLP-1 receptor agonists (see below), according to the FDA. Tirzepatide is similar to semaglutide, but it targets an additional receptor in the body, Batash explains. "It helps regulate blood sugar levels and keeps the users feeling fuller longer between meals, which can contribute to weight loss," Batash says. Tirzepatide is the active ingredient in Eli Lilly's weight-loss medication Zepbound and type 2 diabetes drug Mounjaro.


Ozempic is the brand name for semaglutide, and it's in a class of medications known as glucagon-like peptide 1 (GLP-1) agonists, per the FDA. Ozempic is an injectable medication that is taken once a week, and it's FDA-approved to help with blood sugar management in people with type 2 diabetes. However, it's often prescribed off-label for weight loss, Ali says. "I tell patients that it's a helpful tool," he says. "It's typical for patients to lose about 15% of their body weight over a 10- to 15-month period."


Wegovy is considered a sister medication to Ozempic. "It's the same as Ozempic; it just has different branding," Ali says. Wegovy is also a semaglutide medication but, unlike Ozempic, Wegovy is FDA-approved for weight loss. "Wegovy is similar to Ozempic, but is also available at higher doses," Bansal says. "This drug is highly effective and marks a transformative time in obesity management." Research has found that people on Wegovy can lose an average of 12.4% of their initial body weight.


Mounjaro (tirzepatide) is a medication that's designed to help with blood sugar management in people with type 2 diabetes. Like Wegovy and Ozempic, Mounjaro is an injectable medication. It was approved by the FDA in May 2022 and works similarly to Ozempic. However, Mounjaro targets an additional receptor than Ozempic, Batash explains. While Mounjaro is intended to help patients with type 2 diabetes, it's been prescribed off-label for weight loss as well, Ali says.


Zepbound was recently approved by the FDA to help with weight loss in people who have obesity or are overweight. Zepbound is a sister medication to Mounjaro. Mounjaro is approved by the FDA for the treatment of type 2 diabetes; Zepbound is approved for weight loss, but they are both tirzepatide, Ali says. Bansal compares weight-loss results from Zepbound to that of bariatric surgery, which can lead to weight loss of 10% to 15% of a patient's body weight, and surgical procedures like gastric sleeve, which can lead to 15% to 25% weight loss.


This oral medication is sold under the brand name Contrave. It's designed to help manage chronic obesity in adults, along with diet and exercise. The medications bupropion and naltrexone work together on two areas of the brain — the hunger center and the reward system — to reduce appetite and control cravings, according to the U.S. National Library of Medicine.


Liraglutide is an injectable medication that's used along with diet and exercise to control blood sugar levels in people ages 10 and up who have type 2 diabetes, according to the U.S. National Library of Medicine. However, it can also be used for weight loss management in some adults and children aged 12 and up who weigh 132 pounds or more and who experience obesity or are overweight. The medication, which is sold under the name Victoza when used to treat type 2 diabetes and Saxenda when used for weight loss, helps the pancreas release the proper amount of insulin when blood sugar levels are high. It also slows the emptying of the stomach and may reduce appetite, according to the U.S. National Library of Medicine.


Orlistat is an oral medication used to treat obesity. It's in a class of medications called lipase inhibitors, and it helps to prevent some fat that's eaten from being absorbed in the intestines. (The unabsorbed fat passes through the body during bowel movements.) It's sold under the names Xenical and Alli.


Sold under the brand name Qsymia, it is a combination of the drugs phentermine and topiramate, which are taken orally. The medications are used, along with changes in diet and exercise habits, to treat obesity. The drug, which is designed for people ages 12 and up, works to decrease appetite and help patients feel fuller longer.


Setmelanotide, which has the brand name Imcivree, is an injectable medication designed for weight loss in people ages 6 and up who have obesity due to certain inherited conditions. This drug activates pathways in the brain to encourage weight loss by decreasing appetite and burning more calories.


Glucagon‐like peptide‐1 (GLP‐1) is a gut peptide that influences appetite. GLP-1 also regulates glucose, aka blood sugar. GLP-1 receptor agonists are medications (like Ozempic) designed to lower blood sugar levels and help with weight loss, according to the Cleveland Clinic.


Gastric inhibitory polypeptide (GIP) is another gut peptide. It influences the metabolism of fat, plays a role in the development of obesity and appears to stimulate satiety, or the feeling of being full. In Zepbound and Mounjaro, GIP is paired with GLP-1 receptor agonists, and research shows the duo provides "powerful benefits" for blood sugar control and weight reduction.


Medications that are available for sale, whether over the counter or by a prescription, are approved by the FDA for a particular use, Ali explains. When a medication is used for a reason other than what it was approved for, it's considered "off-label," he says. A good example, points out Ali: Ozempic is often used off-label for weight loss because it's FDA-approved to treat type 2 diabetes. However, it's a semaglutide medication, just like Wegovy, which is FDA approved to help with weight management.


Body mass index (BMI) is a controversial measure of health that puts people into four categories between “underweight” and “obese.” BMI is a person’s weight in kilograms or pounds divided by the square of their height in meters or feet, the Centers for Disease Control and Prevention explains. Having a high BMI can suggest that someone has a lot of body fat, but it's not always accurate, Ali says. Still, patients often need to meet a certain BMI threshold before they can get a prescription for weight-loss medications.


Overweight is defined as having a BMI of 25 to under 30, per the CDC.


Obesity is defined by the CDC as having a BMI of 30 or higher. Obesity is also categorized into these classes:

  • Class 1: BMI of 30 to under 35

  • Class 2: BMI of 35 to under 40

  • Class 3: BMI of 40 or higher


This is an experimental oral medication that's designed to be used once a day to promote weight loss and treat type 2 diabetes. Orforglipron stimulates the pancreas to release insulin when needed and slows down digestion, which can lead to weight loss. The medication is still in clinical trials but has had promising results so far.


This experimental injectable drug is a GLP-1 agonist, like Ozempic and Wegovy, but it also works on GIP (like Zepbound and Mounjaro), as well as a third hormone: glucagon, which can help suppress appetite. The drug has shown promising results in clinical trials so far. Results from a phase 2 clinical trial found that people who took 12 milligrams of the medication lost around 24% of their initial body weight.


Research on the twice-daily pill, which is a GLP-1 agonist, was just halted after drug maker Pfizer said study participants had "high rates" of side effects, including nausea and vomiting, and more than 50% stopped taking the medication. Pfizer reportedly wants to adjust the drug's release mechanism to reduce side effects.

There are several popular weight-loss medications available right now, but doctors caution that these drugs aren't perfect and have been linked to some serious complications. "While taking these medications can help reduce appetite and essentially help people shed pounds, there is no magic pill or quick fix to weight loss," Batash says. "The drugs decrease appetite and slow down the emptying of the stomach, so people feel less hungry and eat less, but they can cause unpleasant gastrointestinal side effects."

If you're interested in taking a weight-loss drug, talk to your doctor, who should be able to offer personalized advice and determine whether one of these medications is right for you.