Mounjaro (tirzepatide) and Wegovy (semaglutide) are two medications that have gained a lot of attention in recent years. Both are part of a new, popular class of injectable drugs. But while they may seem similar, there are key differences between them.

These medications work in different ways. They’re also approved by the U.S. Food and Drug Administration (FDA) to treat different conditions. And depending on your insurance, prices for each medication can vary significantly.

Below, we'll break down the main differences between Mounjaro and Wegovy. Whether you’re considering one of these medications or just want to learn more, this guide will give you a clear overview of how they compare.

What is Mounjaro?

Mounjaro (tirzepatide) is a weekly injectable medication that's approved to treat type 2 diabetes. It's made by the pharmaceutical company Eli Lilly and belongs to a class of drugs called dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonists.

Mounjaro works by activating two different types of receptors in the body at the same time: the glucagon-like peptide-1 (GLP-1) receptor and the glucose-dependent insulinotropic polypeptide (GIP) receptor.

In simpler terms, the medication helps with several important functions:

• Helping your pancreas: Your pancreas controls how much sugar is in your blood via a hormone called insulin, but if you have type 2 diabetes, your pancreas struggles to control how much insulin to release. Mounjaro helps your pancreas release insulin when your blood sugar is high, which lowers your blood sugar levels.
• Slowing down food absorption: When you eat, food breaks down into sugar, which goes into your blood. Mounjaro slows this process down, so sugar enters your bloodstream more slowly.

Mounjaro isn't approved by the FDA to treat obesity, but studies have found that higher doses of tirzepatide (the active ingredient in Mounjaro) can cause significant weight loss. In other words, prescribing Mounjaro for weight loss is an "off-label" use of the medication.

However, Eli Lilly also makes a medication called Zepbound (tirzepatide), which contains the same exact active ingredient as Mounjaro but is FDA-approved for weight loss instead.

What is Wegovy?

Wegovy, another GLP-1 receptor agonist, contains the active ingredient semaglutide (which is also found in Ozempic, a similar medication). Unlike Mounjaro, Wegovy was FDA-approved in June of 2021 specifically for adults with obesity, or those who are overweight with weight-related health conditions like high blood pressure, high cholesterol, or type 2 diabetes.

Like Mounjaro, Wegovy is administered via a weekly injection, and its primary action is to mimic the incretin hormones, which increases insulin production and lowers blood sugar levels. It has shown significant effectiveness in weight reduction, especially when combined with lifestyle changes.

What is more effective, Mounjaro or Wegovy?

Based on clinical trials, tirzepatide (Mounjaro's active ingredient) may be more effective for weight loss than semaglutide (Wegovy's active ingredient).

In 2025, a head-to-head study of both medications found that adults with obesity lost an average of 20.2% of their body weight with tirzepatide after 72 weeks, compared to 13.7% with semaglutide.

That said, results can vary based on your health, medication dosage, weight, and how well you stick to your treatment plan.

What are the side effects of Wegovy and Mounjaro?

Gastrointestinal (GI) issues like nausea, constipation, diarrhea and vomiting are the most common side effects of Wegovy and Mounjaro.

However, in clinical trials, Wegovy users were more more likely to experience GI issues than Mounjaro users:

• 44% of Wegovy users reported nausea compared to 12% of Mounjaro users
• 30% of Wegovy users reported diarrhea compared to 12% of Mounjaro users
• 24% of Wegovy users reported constipation compared to 6% of Mounjaro users
• 24% of Wegovy users reported vomiting compared to 5% of Mounjaro users

Other common side effects for both medications include belching, fatigue, dizziness, and headaches. Less common but serious risks include allergic reactions, low blood sugar (hypoglycemia), gallbladder disease, pancreatitis, and an increased risk of thyroid cancer.

If you experience severe or persistent side effects while using either medication, contact your healthcare provider.

You should avoid both medications if you are pregnant or trying to become pregnant. You should not take Mounjaro or Wegovy if you have history of pancreatitis, Type 1 diabetes, diabetic retinopathy, or a personal or family history of medullary thyroid cancer or multiple endocrine neoplasia syndrome type 2 (MEN 2).

Which drug is more expensive, Mounjaro or Wegovy?

The price you pay for GLP-1 medications depends on your insurance status.

With insurance, the price of these medications will vary based on the rates negotiated by your insurer.

Without insurance, Mounjaro (tirzepatide) is about $1,080 per month out of pocket. Wegovy (semaglutide) costs is $1,349 out of pocket. However, there is a self-pay Wegovy option available for cash-pay patients that is priced at just $499 per month.

Do Wegovy and Mounjaro have generic versions?

Currently, there are no generic versions of either Mounjaro or Wegovy available. Both medications are relatively new, meaning they are still protected by patents. For the time being, only the brand-name versions are available, which contributes to their high price.

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