Mounjaro vs. Ozempic

The most significant differences between Ozempic (semaglutide) and Mounjaro (tirzepatide) are their active ingredients and FDA indications. Both are FDA-approved medications for Type 2 diabetes, but Ozempic is also approved to reduce cardiovascular risks and cater to diverse metabolic health needs. 

Eli Lilly — which makes Mounjaro — released another tirzepatide medication called Zepbound, which was FDA-approved to treat weight loss in 2023. Likewise, Novo Nordisk — which makes Ozempic — also makes Wegovy, another semaglutide that is FDA-approved for weight loss.

Both Mounjaro and Ozempic may be prescribed off-label for weight loss, but the manufacturers warn against off-label uses.

Ozempic and Mounjaro are each available in different dosages. You inject your dose using a prefilled pen injector once weekly. Each Ozempic pen may contain more than one weekly dose per pen.

Health care providers advise against combining Mounjaro and Ozempic because of potential side effects. Both drugs help manage Type 2 diabetes, but taking two GLP-1 medications at the same time is not recommended. 

Usage Differences Between Mounjaro and Ozempic

While Mounjaro and Ozempic are both diabetes drugs, they have become popular for weight loss as demand for Wegovy and Zepbound faced shortages. Truveta Research, a coalition of more than 30 health care systems in the U.S., compared Mounjaro and Ozempic based on prescribing and dispensing rates, patient characteristics and other criteria.

Truveta’s research was based on electronic medical data from health care institutions providing 18% of the daily clinical care in the U.S. The analysis reviewed records of more than one million patients prescribed a GLP-1 between January 2018 and December 2023.

Both drugs help manage Type 2 diabetes. Mounjaro suppresses glucagon, a blood sugar-elevating hormone called GLP-1, and offers comprehensive diabetes management. Ozempic also enhances fullness and lowers blood glucose.

Mounjaro, a dual GIP and GLP-1 receptor agonist, offers enhanced appetite and blood sugar control mechanisms. This dual action could lead to more weight loss than medications targeting GLP-1. While research shows Mounjaro is more effective for blood sugar control and weight loss, it is more expensive and may have additional side effects.

While multiple studies show Mounjaro is more effective than Ozempic for weight loss, the FDA has not approved it for that use. But doctors may sometimes prescribe both Mounjaro and Ozempic off-label for weight loss. 

Another study by Truveta Research compared Mounjaro’s and Ozempic’s active ingredients in overweight and obese adults. In the real-world comparative effectiveness study, tirzepatide proved more effective for weight loss within a year of treatment. 

Tirzepatide users had higher success rates for body weight loss and significant weight loss at three, six and 12 months of treatment.

According to Eli Lilly, participants in Mounjaro clinical trials lost 12 to 25 pounds, with a reported 21.1% weight loss after 12 weeks and a total mean weight loss of 26.6% over 84 weeks.

In clinical trials by Novo Nordisk, Ozempic users lost between 9.3 and 14.1 pounds. On average, they lost about 15% of their body weight after 68 weeks.

The more effective medication depends on your individual needs. While Mounjaro is known for effectively reducing A1C levels and weight, Ozempic also addresses cardiovascular risks associated with Type 2 diabetes.

Several studies have shown that Mounjaro is more effective than Ozempic for blood sugar control and weight loss.

In the SURPASS-2 trial, tirzepatide outperformed semaglutide in reducing A1C levels. Tirzepatide’s 5 mg, 10 mg, and 15 mg doses showed A1C reductions of 2.01, 2.24 and 2.30, respectively, surpassing semaglutide’s 1.86 reduction at the 1 mg dose.

The drugs have similar side effects, but Mounjaro side effects may be more numerous — and more severe.

“The SURPASS-2 trial, [which] checked head-to-head tirzepatide and semaglutide, results indicated that most common side effects were not significantly different between tirzepatide and semaglutide,” Dr. Eldad Einav, a cardiologist and weight loss specialist, told Drugwatch. “Tirzepatide show[ed] a slightly higher rate of serious adverse events compared to semaglutide.”

Mounjaro’s prescribing information warns of severe gastrointestinal disease, while Ozempic’s does not. In clinical trials, more people stopped taking Mounjaro due to gastrointestinal side effects, and both medications had more side effects at higher doses.

“When comparing the side effects of Ozempic and Mounjaro, it is important to note that each medication affects the body differently, and individual experiences may vary,” Dr. David Smith, urologist and co-founder of medical device company BladGo Medical, told Drugwatch.

There have also been reports of urinary tract infections, or UTIs, as a rare Ozempic side effect.

“Those who have a history of urinary tract infections may want to avoid Ozempic,” Smith said. “Similarly, individuals who have a history of gastrointestinal issues may want to avoid Mounjaro.”

Smith added that you should talk with your doctor about your medical history to determine which drug may be better for you.

Both drugs have FDA boxed warnings for thyroid gland tumors, including cancer. The drugs also warn about side effects like pancreatitis, diabetic retinopathy, low blood sugar, kidney problems, allergic reactions and sudden gallbladder disease. In cases, the drugs may cause ileus, a digestive problem leading to bowel movement difficulties.

Mounjaro and Ozempic Safety Concerns and Lawsuits

Both patients taking Mounjaro and those taking Ozempic have reported severe gastrointestinal problems leading to hospitalization. Mounjaro’s label advises against using the drug in patients with gastroparesis. 

In August 2023, a patient filed both Ozempic and Mounjaro lawsuits after experiencing severe gastroparesis after taking both drugs. The patient experienced chronic, severe vomiting that required hospitalization.

Taking Ozempic or Mounjaro may interact with certain medications, leading to an increased risk of hypoglycemia and affecting the effectiveness of oral medications due to changes in stomach emptying.

If you take sulfonylurea or insulin, consult with your doctor about possibly reducing your medication dose while on either drug.

Mounjaro’s drug label recommends using a non-oral contraceptive method or adding a barrier contraceptive for four weeks after starting treatment and for four weeks after each dose escalation.

Mounjaro is more expensive than Ozempic. In early 2024, the cost of Ozempic without insurance started at around $935 a month in the U.S. Mounjaro’s list price was $1,069 per fill, according to the Eli Lilly website. Some reports say the drug can cost as much as $1,267.

Insurance may cover drug costs for diabetes treatment, but weight loss patients face approval challenges. Novo Nordisk and Eli Lilly offer discount programs for eligible patients.

“I’m very blessed to have insurance pay 100% of my Mounjaro,” Barb Herrera, a health care blogger who takes Mounjaro for Type 2 diabetes, told Drugwatch. “I am grateful and hope my insurance continues to pay for it.”

She said she knows several people without insurance who rely on compounding pharmacies to buy versions of semaglutide or tirzepatide.

Choosing between Mounjaro and Ozempic depends on your specific medical requirements.

For instance, the FDA approved Ozempic in March 2024 to prevent heart complications in overweight and obese adults.

“People with preexisting coronary disease will benefit from semaglutide based on the SELECT trial showing 20% less heart attack and stroke in patients taking Wegovy for weight loss,” Dr. Einav said. “Tirzepatide does not [yet] have this data.”

Ozempic lowers A1C levels, aids in weight loss and reduces the risk of cardiovascular events in people with established cardiovascular diseases.

Mounjaro is more effective for weight loss and reducing A1C levels, but it may cause severe gastrointestinal side effects. Before deciding, consult your health care provider to discuss the benefits and drawbacks of each medication.