What's the Difference Between Ozempic, Wegovy, and Mounjaro?

• Physicians may prescribe type 2 diabetes drugs to lower blood sugar levels and promote weight loss in patients who meet specific criteria.

• These drugs can also lower the risk of events like heart attack or stroke.

• While using type 2 diabetes drugs off-label for weight loss can be extremely effective, they are generally not recommended for people who are not overweight or living with obesity.

Ozempic, Wegovy, and Mounjaro are all drugs that can be used to treat type 2 diabetes. But you’ve likely heard of them because they’re all over the news lately—especially for the controversy surrounding their use for weight loss among celebrities.

While it’s important to know healthcare providers are not against their off-label use for weight loss in people who need it—in fact, Wegovy is FDA-approved for weight loss—there are differences between these drugs, how they work, and what they’re currently indicated for.

Here’s what you need to know. 

Ozempic (semaglutide)

Ozempic, also known as semaglutide, is a prescription drug used to manage type 2 diabetes alongside diet and exercise. The drug, made by pharmaceutical company Novo Nordisk, helps improve blood sugar controls and lowers the risk of events like heart attack or stroke.

It is important to note that Ozempic is not used to treat type 1 diabetes, and is not insulin. 

What Is Ozempic Approved For?

In the U.S., the FDA has approved Ozempic for type 2 diabetes and to help prevent serious cardiovascular events such as heart attack or stroke in people with type 2 diabetes and cardiovascular disease.

Ozempic may also be used off-label for weight loss in patients who are overweight to improve health outcomes, like high blood pressure, Jamie Alan, PharmD, PhD, an associate professor of pharmacology at Michigan State University, told Verywell. High blood pressure, or hypertension, is more common in overweight patients.

“The ideal candidate for these medications is anyone that needs to lose weight, has diabetes, and needs to have their risk of cardiovascular complications (i.e. heart attack or stroke) reduced,” Kunal Shah, MD, an assistant professor of endocrinology at Rutgers University in New Brunswick, New Jersey, told Verywell. “Ozempic has been shown to reduce these risks.”

A criticism surrounding Ozempic is that providers prescribe it too liberally for weight loss. Because it's not currently FDA-approved for obesity or weight loss, there are no official parameters for who should receive it in order to lose weight. However, experts suggest an appropriate candidate should meet the requirements for other weight control medications, which include either:

• Lack of weight loss or inadequate weight loss after six months of lifestyle changes and a BMI 30 or greater

• A BMI of 27-29.9, plus a weight-related health condition like diabetes, prediabetes, or hypertension)

How Does Ozempic Work?

The drug works by improving patients’ blood sugar levels and reducing their appetite. It also helps prevent the liver from releasing too much sugar. Ozempic belongs to a drug called glucagon-like peptide 1 (GLP-1) receptor agonists.

“GLP-1 is also called an incretin, and incretins have very complex actions on our body,” Alan said. “One of the things that they do is increase insulin, and they also increase insulin sensitivity. That’s the primary mechanism for how they treat diabetes.”

A secondary mechanism, Alan explains, contributes to weight loss. Ozempic promotes satiety—in other words, provokes a feeling of fullness. This happens because the drug slows down your digestive system so you feel fuller longer.

“[These drugs] have also been shown to reduce cravings for things like sugar,” Alan said.

Because of the way Ozempic works, people who might not be clinical candidates for these drugs can find them attractive. These drugs can be very effective—and a good tool in the toolbox—to help with weight loss in overweight or obese patients, Alan said, but inappropriate use can be dangerous.

“There are legitimate weight loss uses for these drugs in the appropriate patients,” Alan says. “But the idea of using a drug to lose weight—when you do not need to lose weight—promotes a really toxic diet culture that I personally feel needs to stop.”

How Do You Take Ozempic?

Ozempic is taken via injection.

“Ozempic uses a traditional insulin pen-type device,” Andrew Kraftson, MD, an associate professor of endocrinology at the University of Michigan, told Verywell. It can be injected under the skin of the abdomen, thigh, or upper arm.

The drugmaker of Ozempic says you should not inject the medication into a muscle or vein, or mix insulin and Ozempic together in the same injection. Patients should also rotate their injection site with each dose.

The dosage of the drug depends on the patient and their needs. For patients who are using Ozempic for type 2 diabetes and lowering the risk of heart attack or stroke, 0.25 milligrams (mg) is injected once a week for four weeks at first, then increased to 0.5 mg. Healthcare providers might increase the dose as needed, but it’s vital to consult with them before making any change yourself.

Ozempic Side Effects

Ozempic can cause nausea, vomiting, and diarrhea.

“If you are not eating as much, and you’re feeling nauseated, vomiting, and having diarrhea, then dehydration is certainly also a risk,” Kraftson said.

There’s also a chance people will experience constipation due to the fact that the drug slows down their digestive system, meaning food sits in the stomach longer.

Rare but severe side effects may include thyroid tumors, which have only been seen in animal studies, as well as gallbladder problems and kidney issues.

“On the label, there are significant risks listed such as pancreatitis that worry people,” Kraftson said. “Recent data has been reassuring that the risk of pancreatitis is pretty minimal, and we really don’t think that the thyroid cancer risk occurs outside of the rodent population.”

Pancreatitis refers to inflammation of the pancreas, a gland behind the stomach. The condition occurs when digestive enzymes activate and attack the pancreas, and can lead to organ damage if untreated.

For people with a history of disordered eating, the medication might trigger or worsen the illness due to the fact it causes reduced appetite and weight loss, Kraftson said.

“You could be—for lack of a better term—‘feeding into’ an eating disorder by adding the medication if you’re not addressing underlying mental health issues,” he said.

Then, there’s “Ozempic face.” Some patients who have used diabetes drugs have noticed facial aging and sagging due to sudden weight loss, causing a loss of fat in their face. But experts say any weight loss can result in facial changes.

“It’s purely cosmetic. It is not anything pathological,” Alan said. “But it does trouble some patients.”

Wegovy (semaglutide)

Ozempic and Wegovy are the same medication (semaglutide) and work the same way, says Alan, though Wegovy has a higher maximum dose.

“While they’re the same drug, they’re under different brand names and have a slightly different dosing schedule,” she said.

Both drugs are manufactured by Novo Nordisk. The major difference is what they are FDA approved for.

What Is Wegovy Approved For?

While Ozempic is FDA approved for diabetes, Wegovy has full FDA approval for weight loss. In June 2021, Wegovy was approved for chronic weight management in patients with:

• A body mass index (BMI) of 27 kg/m² or greater with at least one weight-related condition, like high blood pressure, type 2 diabetes, or high cholesterol

• A BMI of 30 kg/m² or greater

How Does Wegovy Work?

Kraftson said that Wegovy, just like Ozempic, is a GLP-1 receptor agonist. It helps regulate blood sugar and keeps the body fuller longer between meals, which can contribute to weight loss. The drug also helps suppress the liver from producing too much sugar.

“[These drugs] regulate how quickly or how slowly food goes through the digestive tract—they actually slow things down,” Kraftson said. “Food sits in the stomach longer, and so you feel fuller because it’s sitting there.”

How Do You Take Wegovy?

Like Ozempic, Wegovy is taken by injection. But instead of an insulin-type device, Wegovy is injected via something that looks more like an epipen, Kraftson says. It should be injected under the skin once a week in the upper arms, abdomen, or upper legs.

The drugmaker says patients typically start a dose of 0.25 mg once weekly for four weeks before upping the dose in intervals, reaching 2.4 mg.

“We’ve been using these types of medications since 2005 to treat diabetes, and there’s been a progression,” Kraftson said. “It used to be that people would have to inject twice a day, and then there became a once-daily product. Now, we’re in the status of mostly using the once weekly self-injections.”

Wegovy Side Effects

Patients on Wegovy might experience common GI side effects, including feeling nauseous because food contents are sitting in the stomach a little bit longer.

“That will subside in some patients, but may not subside in all patients,” Alan said.

There’s also all the same other side effect risks as there are with Ozempic, like constipation, upset stomach, diarrhea, and vomiting, so consulting your healthcare provider to determine if the drugs are right for you is very important.

“Taking these medications without being medically supervised can result in a lot of those side effects,” Shah said. “In addition, these meds have not been studied in pregnancy and can be a potential risk to a growing baby if someone gets pregnant while on these medications.”

The drugmaker says Wegovy may cause serious side effects, including pancreatitis, gallbladder problems, and kidney problems. It also warns of possible thyroid tumors, including cancer.

Mounjaro (tirzepatide)

Eli Lilly’s drug Mounjaro is used to help manage type 2 diabetes, along with diet and exercise. While its function is the same as the other drugs, it’s slightly different from Ozempic and Wegovy.

Mounjaro is the first of its kind that targets two major hormones that regulate blood sugar levels and can help patients lose weight: GLP-1 and glucose-dependent insulinotropic polypeptide (GIP).

“Mounjaro is the newest drug on the market, and it’s in the same class as Ozempic and Wegovy, but with another compound built in to strengthen the effects,” Shah said.

What Is Mounjaro Approved For?

In May 2022, Mounjaro was approved by the FDA for the treatment of type 2 diabetes. While it is not yet approved for weight loss, it might be used off-label for obesity—and soon to be approved for it.

“Mounjaro is on the fast-track to be approved for weight loss,” Kraftson said.

How Does Mounjaro Work?

Like the other type 2 diabetes medications, Mounjaro lowers blood sugar levels, increases insulin sensitivity, slows the digestive system and decreases appetite. It also causes patients to lose weight.

Because Mounjaro targets two hormones that have key metabolic roles, patients might experience greater weight loss, Alan said.

“We are seeing some more significant weight loss with the dual incretin [of Mounjaro] versus the single incretin medications,” she said. “My guess is this is because you're having additive effects of…two incretins and not just one.”

How Do You Take Mounjaro?

Mounjaro is a once-a-week injection. It can be used in addition to insulin, but the drugmaker warns against mixing insulin and Mounjaro in the same injection.

Patients typically start with a weekly 2.5 mg dose. Mounjaro should be injected under the skin of the abdomen, thighs, or the back of the upper arm.

Mounjaro Side Effects

The most common side effects of Mounjaro, according to the drugmaker, include nausea, diarrhea, decreased appetite, vomiting, constipation, indigestion, and stomach pain.

There are serious side effects too, which are more rare. These include pancreatitis, low blood sugar, kidney failure, allergic reaction and gallbladder problems, among others.

Patients need to know that Mounjaro may cause tumors in the thyroid, and patients with a family history of a certain type of thyroid cancer—medullary thyroid carcinoma—should not use the medication.

If a patient is a good candidate for the drug, Shah said it can improve their health. Obesity is a chronic medical condition, just like high blood pressure, and these meds can help manage it long-term.

“These are fantastic medications: They are game-changers for people who have done all of the dieting, all of the exercise, and have sacrificed a lot to get healthy,” Shah said. “But powerful medications can have powerful side effects. It’s important to take these medications under the guidance of a licensed medical physician that properly understands the risks and benefits.”