How does the weight loss drug Zepbound compare to Mounjaro, Wegovy and Ozempic?

FDA-approved Zepbound is the brand name for tirzepatide when doctors prescribe the medication for weight loss. Zepbound and other weight loss drugs are extremely expensive, and most insurance companies don't cover them. Experts hope increased competition among drug makers will drive down costs and improve patient access to pricey weight loss medications. Photo: Getty Images
FDA-approved Zepbound is the brand name for tirzepatide when doctors prescribe the medication for weight loss. Zepbound and other weight loss drugs are extremely expensive, and most insurance companies don’t cover them. Experts hope increased competition among drug makers will drive down costs and improve patient access to pricey weight loss medications. Photo: Getty Images

A newly approved weight loss drug called Zepbound may work even better than the popular drug Wegovy while also driving down the cost of multiple weight loss drugs.

The newest crop of weight loss drugs — including Zepbound — have sticker prices of more than $1,000 per month, and most insurance companies do not cover them. Doctors and patients, alike, are eager see if Zepbound will foster greater competition and price cuts among drug makers, thus improving access to pricey medications.

Medical experts at the U.S. Food and Drug Administration (FDA) gave a much-anticipated green light to Zepbound on Nov. 8.

The FDA previously approved a related drug called Mounjaro, which is made from the same active ingredient in Zepbound: tirzepatide. But Mounjaro was only available to people with Type 2 diabetes.

Approval of Zepbound is highly significant as the new drug and other similar medications change the way both patients and doctors view battles with extra pounds. About 70% of adults in the U.S. have a body mass index or BMI in the overweight or obese range.

“This particular medication opens up a new era for obesity medications. It is the first combination peptide to get FDA approval for obesity,” said Dr. Cecilia Low Wang, a UCHealth expert on endocrinology, diabetes and metabolism. “I’m super excited because this drug is so effective in helping people with obesity, which is a challenging medical condition.”

While the drugs have produced dramatic results in people who have used them so far, Low Wang underscores the importance of physical activity and healthy eating.

“I’m glad we now have potent medications for obesity, but these drugs are not a replacement for healthy lifestyle changes. To be healthy, people need to make sure they exercise most days of the week and consistently choose healthy foods,” Low Wang said.

So, what is Zepbound? How well does it work? What’s up with the weird name? How is Zepbound related to Mounjaro, Wegovy and Ozempic? How much will Zepbound cost, and will it cause negative side effects like the gastrointestinal problems that Wegovy and Ozempic can cause?

To answer all of your questions about Zepbound, we consulted with Low Wang, who is a professor at the University of Colorado School of Medicine on the Anschutz Medical Campus.

She also chairs the committee that advises the FDA about drugs related to endocrinology and metabolism. (Low Wang does not receive funding from the drug companies. And her views do not represent those of the FDA or the FDA Endocrinologic and Metabolic Drugs Advisory Committee.)

What is Zepbound?

Zepbound is the brand name for the drug tirzepatide when doctors prescribe it for weight loss. Mounjaro is the name of the medication when it’s used to treat diabetes. (Learn all about Mounjaro.) Both Zepbound and Mounjaro are brand names for the generic drug, tirzepatide.

How do you take Zepbound? Is it a pill?

No. Zepbound is not a pill. It’s an injectable medication that patients need to use once a week. It comes in three doses: 5, 10 and 15 milligrams. So far, Zepbound, Mounjaro, Ozempic, and Wegovy are all injections. The drug in Ozempic and Wegovy, semaglutide, is also available in a pill form for Type 2 diabetes called Rybelsus, and doesn’t cause as much weight loss.

How does Zepbound work? Why does it trigger dramatic weight loss?

“It suppresses appetite and makes you feel more full. It changes the rate at which your stomach empties,” Low Wang said.

How much weight do people lose with Zepbound?

During clinical trials, study volunteers who used tirzepatide lost as much as 21% of their body weight.

The average weight loss for study subjects who did not have diabetes and used the largest dose of Zepbound (15 milligrams, once a week) was 18%, according to the FDA.

People who have diabetes tend to lose less weight with these new drugs than those who don’t have diabetes. Another study found that people with diabetes who used Zepbound lost an average of 12% of their body weight, FDA officials said.

Tell me more about Zepbound vs. Mounjaro vs. Wegovy vs. Ozempic

All of these drugs are part of a new class of weight loss medications that are shaking up treatment of obesity and diabetes. They’re also sparking drug shortages and economic earthquakes around the world since demand for the drugs is so high. (Read how Wegovy and Ozempic are causing huge economic impacts in Denmark, home of the drug’s maker.)

Many people – including those who don’t have obesity or medical conditions associated with being overweight – have been clamoring to get the medications because they are powerful appetite suppressants and work so much better than previous generations of weight loss drugs.

Zepbound and Mounjaro are basically the same drug, but they’re approved for different medical conditions: Zepbound for weight loss and Mounjaro for diabetes.

Similarly, Wegovy and Ozempic are the same drug, but with different names and different doses for different conditions. Wegovy is the name of the drug as it’s prescribed for weight loss. Ozempic is the name of the drug as it’s used for diabetes. The generic name for Wegovy and Ozempic is semaglutide.

So, are Zepbound, Mounjaro, Ozempic and Wegovy all the same?

No. Zepbound and Mounjaro (also known as tirzepatide) work a little differently than Ozempic and Wegovy (also known as semaglutide).

Here are the differences.

First, the drugs are made by different drug companies. Competition between these pharmaceutical companies and others that are working on new weight loss drugs may drive down prices for the expensive medications.

Eli Lilly makes Zepbound and Mounjaro while Novo Nordisk makes Wegovy and Ozempic.

Eli Lilly is based in the United States while Novo Nordisk is based in Denmark.

Zepbound, Mounjaro, Wegovy and Ozempic work in similar ways to reduce appetite. But Zepbound and Mounjaro are what’s called “dual-agonist” drugs while Wegovy and Ozempic are what’s known as “single-agonist” drugs. These drugs activate important hormone pathways in the body.

“Tirzepatide is in a completely new drug class,” Low Wang said. “It’s a combination peptide. This dual agonist approach seems to cause people who use Zepbound or Mounjaro injections to lose even more weight than those who use a medication that only activates one hormone pathway.”

These drugs stimulate hormones that help control blood sugar levels and reduce appetite, triggering weight loss.

The hormones are glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP).

Wegovy and Ozempic activate the GLP-1 pathway, while Zepbound and Mounjaro activate two: both GLP-1 and GIP.

What’s up with the weird name?

Drug makers spend considerable time and money creating brand names for drugs. Presumably, the “zep” in Zepbound comes from tirzepatide, the generic name for the drug from which Zepbound is made.

Low Wang says that drug makers come up with names that may sound strange to patients because the names need to sound OK in multiple languages, and the drug names can’t conflict with or sound too much like existing brand names for pharmaceuticals. Low Wang concedes that the names often sound strange, and Zepbound may be hard for some people to pronounce. But judging by the popularity of the other weight loss drugs, Zepbound may soon become familiar to millions of people around the world.

Is Zepbound a prescription medication?

Yes. Zepbound – just like Mounjaro, Wegovy and Ozempic – is a prescription medication. If you think you might benefit from using a weight loss drug, schedule an appointment with your doctor.

Who is eligible to receive Zepbound?

The FDA approved Zepbound for adults ages 18 and older who are dealing with obesity or are overweight and have additional weight-related health challenges.

Doctors use BMI to classify who is obese or overweight. Low Wang said BMI is far from a perfect measure of a person’s health. Some people have a higher BMI and are perfectly healthy. These drugs may not be right for them.

“An elevated BMI doesn’t tell you everything about a person’s health,” Low Wang said. “A person could be very fit and muscular, and have a higher BMI, but wouldn’t need this medication.”

Meanwhile, other people who have high BMIs are dealing with serious related health problems like high blood pressure, diabetes, and elevated risk of heart attack, stroke, heart failure or liver disease.

Low Wang encourages people to consult with their doctors.

To qualify for Zepbound, patients need to have a BMI of 30 and higher – which means they’re dealing with obesity – or a BMI of 27 or greater – the marker for being overweight – while they are also dealing with at least one other weight-related health condition. These conditions include high blood pressure, high cholesterol or Type 2 diabetes.

What are the side effects that patients experience with Zepbound?

The common side effects are very similar to those that patients have experienced with Mounjaro, Wegovy and Ozempic. The most common side effects include nausea, vomiting, diarrhea, decreased appetite, constipation, upper abdominal discomfort and abdominal pain.

In addition, FDA officials have warned that tirzepatide can cause thyroid C-cell tumors in rats. Federal health experts don’t know yet whether Zepbound and Mounjaro cause similar tumors — including medullary thyroid cancer — in humans.

Can weight loss drugs cause depression or suicidal thoughts?

It’s not clear whether Zepbound or other weight loss drugs can case depression or suicidal ideation. But Zepbound’s drug maker, Eli Lilly, has included a warning with the drug that doctors should monitor their patients for depression or suicidal ideation and should advise patients to  immediately stop using Zepbound if they are experiencing any suicidal thoughts.

“We’ve had this problem with previous weight loss drugs, where they might increase risk of suicide in people with depression,” Low Wang said.

Are stomach problems, nausea and vomiting common for everyone who uses Zepbound, Mounjaro, Ozempic and Wegovy?

Some patients report gastrointestinal problems with these drugs, but many do not have any problems, Low Wang said.

“A portion of people who are taking these drugs will have side effects, but a majority tolerate these medications well,” Low Wang said.

Her patients have had the best luck when they start with the lowest dose and let their bodies get used to it.

“We start patients on a low dose for four weeks, then step up on the dose,” Low Wang said.

How can people reduce unpleasant gastrointestinal side effects with Zepbound, Mounjaro, Ozempic and Wegovy?

Low Wang has found that patients do well if they pay close attention to when they start feeling full and stop eating at that point. People will end up dramatically reducing how much they eat. For those who love to eat and cook, taking the drugs can be a challenge.

In addition, foods that are rich in fat tend to increase negative gastrointestinal side effects.

I hear all of these drugs are very expensive. How much will Zepbound cost?

The list price of Zepbound is more than $1,000 per month. And most health insurance companies are not yet covering these new weight loss medications. All of them are very expensive now. But Low Wang and other experts are hoping that increased competition among drug makers will drive down the costs of the medications.

In addition, recent studies of people using semaglutide, the active ingredient in Ozempic and Wegovy, suffered dramatically fewer adverse cardiovascular events like heart attacks and strokes. The studies have found benefits in both people with diabetes and those who were obese but did not have diabetes.

It will take time before researchers complete studies to determine if Zepbound produces similarly positive cardiovascular benefits.

If the drugs help people lose weight while also preventing heart attacks, strokes and other cardiovascular health problems, Low Wang expects more insurance companies to cover the drugs. Pressure also could increase for the federal government to cover the drugs through Medicare and Medicaid.

What are the pros and cons of using Zepbound?

The pros are that Zepbound helps many people lose a dramatic amount of weight. It may also help reduce other health problems associated with excess weight.

There are multiple potential downsides to using Zepbound, Mounjaro, Ozempic and Wegovy. (Read more about eight reasons to be cautious about Ozempic and Wegovy.)

Here are some reasons to be cautious about Zepbound:

  1. Just like Ozempic and Wegovy, if you lose weight with Zepbound or Mounjaro, you likely will need to keep using the medication forever to keep the weight off.
  2. Zepbound is expensive, and it may be hard to get.
  3. Like Wegovy and Ozempic, Zepbound and Mounjaro can cause unpleasant gastrointestinal side effects.
  4. All of these weight loss drugs are relatively new. It’s possible that some long term health effects could emerge.
  5. Zepbound might exacerbate depression or suicidal thoughts in some people. Anyone who experiences depression or suicidal thoughts should immediately contact their doctor, and Eli Lilly, the maker of Zepbound, advises people to immediately stop using the drug if they are having suicidal thoughts.

Low Wang emphasizes that it’s vital for individuals to speak with their doctors.

“Patients have to use reliable sources for their medical information, and doctors need to think about an individual’s risk-benefit balance. For each person, it’s going to be different,” she said.

Low Wang encourages patients to review information from reliable experts including the Endocrine Society and the American Association of Clinical Endocrinology or AACE.

Are there people who should not take Zepbound?

Yes. People who are pregnant should never take these medications. They need to be eating well and gaining weight to support their pregnancies.

FDA officials say people who have a personal or family history of medullary thyroid cancer should not use Zepbound along with patients with Multiple Endocrine Neoplasia syndrome type 2.

In addition, Zepbound has not been studied in patients with a history of pancreas inflammation (pancreatitis) or severe gastrointestinal disease (including severe gastroparesis, a condition that affects normal movement of the muscles in the stomach), according to the FDA.

What do you expect down the road with weight loss drugs?

Low Wang said many new drugs are being developed now.

“There are going to be many more combination peptides – dual agonists and triple agonists,” she predicted.

In addition to double peptide medications, like Zepbound, there will also be triple peptide drugs.

“We have to be aware of all of the side effects, and people should talk to their doctors. But the future for obesity treatment is really exciting.”


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