Wegovy vs. Mounjaro: Differences, Dosage, and Side Effects

Get the facts on two of the most popular weight loss drugs, their side effects, and which may be right for you.

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by
Rebecca Washuta
— Signos
MS, CNS, LDN
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Reviewed by

Rebecca Washuta
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Updated by

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Science-based and reviewed

Published:
July 24, 2024
February 9, 2024
— Updated:

Table of Contents

It seems like GLP-1 receptor agonist drugs have flooded the market recently, making it difficult to understand the differences and decide which (if any) may be right for you. Two of the most popular drugs in this category are Wegovy and Mounjaro. Wegovy (semaglutide) is made by Novo Nordisk and is FDA-approved for weight loss, while Mounjaro (tirzepatide) is made by Eli Lilly and is FDA-approved for type 2 diabetes. 

Despite these different clinical indications, there is a lot of overlap between these two drugs, and Mounjaro may be prescribed for off-label use as a weight-loss medication. In this article, we’re breaking down everything you need to know about these two drugs. 

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Main Differences Between Mounjaro and Wegovy

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While both of these drugs can help people reduce their body weight, the biggest difference is the conditions they are intended to treat. 

Wegovy is approved by the Food and Drug Administration for weight loss and is intended for adults with obesity (a body mass index (BMI) of 30 or higher). It can also be used for adults with a BMI of at least 27 who have one or more weight-related health conditions (like high blood pressure, high cholesterol, cardiovascular disease, etc.). In clinical trials for Wegovy, patients with type 2 diabetes were excluded. Therefore, its safety and effectiveness for people living with diabetes have not been established, and it should not be prescribed for people with this condition.1

Mounjaro is approved by the Food and Drug Administration for type 2 diabetes and has been shown to lower hemoglobin A1C and improve glucose control. Patients taking Mounjaro have reported significant weight loss as a side effect; however, Mounjaro is not intended to be a weight loss drug. In clinical trials for Mounjaro, all patients had type 2 diabetes, so it should not be prescribed solely for its weight loss benefits.2

These drugs contain different biomolecules as their active ingredients. The active ingredient in Wegovy is semaglutide, which is a glucagon-like peptide-1 receptor agonist (GLP-1 RA). This is the same active ingredient as the popular drug Ozempic; however, Ozempic is only intended for patients with type 2 diabetes, as opposed to Wegovy, which is intended specifically for weight loss. 

The active ingredient in Mounjaro is tirzepatide. Tirzepatide is part of a new class of drugs, which are dual GLP-1 and GIP (glucose-dependent insulinotropic polypeptide) receptor agonists. 

Both medications work slightly differently in the body. Wegovy (semaglutide) works by activating GLP-1 receptors. GLP-1 receptors are found in the pancreas, nervous system, and various other tissues in the body. In the pancreas, Wegovy works by stimulating the release of insulin, which allows cells to absorb glucose from the bloodstream, reducing blood sugar spikes. It also works on GLP-1 receptors in the brain to decrease food intake and increase satiety.3

Mounjaro (tirzepatide) works on both GLP-1 receptors and GIP receptors. Similar to Wegovy, Mounjaro stimulates insulin release from the pancreas, which reduces blood sugar. Additionally, it increases the levels of adiponectin, which increases insulin sensitivity, further improving glucose and fatty acid metabolism and leading to increased weight loss.4, 5

Wegovy vs Mounjaro: Dosage and Administration

Both Wegovy and Mounjaro are injectable medications that have various dosage forms and strengths. They are both administered subcutaneously once per week by a single-use pen. Recommended sites for the weekly injection are the upper arm, upper leg, or abdomen. 

Below are examples of typical dose escalations for each drug.

Wegovy Dosage

  • Month 1: 0.25 mg once per week (starting dosage)
  • Month 2: 0.5 mg once per week
  • Month 3: 1.0mg once per week
  • Month 4: 1.7mg once per week (maintenance dose)6

Mounjaro Dosage

  • Month 1: 2.5 mg once weekly (starting dosage)
  • Month 2: 5 mg once weekly (maintenance dose)
  • If additional glycemic control is needed, your doctor may recommend higher doses. Dose options are 7 mg, 10 mg, 12.5 mg, or the maximum 15 mg.7 

<p class="pro-tip"><strong>Also Read: </strong><a href="saxenda-vs-wegovy">Saxenda vs Wegovy: What Is The Difference?</a>.</p>

Side Effects of Wegovy vs. Mounjaro

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Despite their impressive efficacy for weight loss and glucose control, both Wegovy and Mounjaro can have side effects ranging from unpleasant to very serious. It’s important you talk to your doctor about the potential risks before starting any new medication. 

Wegovy Common Side Effects

  • Nausea
  • Diarrhea
  • Vomiting
  • Abdominal pain
  • Headache
  • Fatigue 
  • Dizziness

Wegovy Serious Side Effects

  • Thyroid cancer
  • Pancreatitis
  • Gallbladder disease
  • Kidney injury
  • Suicidal behavior and ideation

Mounjaro Common Side Effects

  • Nausea
  • Diarrhea
  • Vomiting
  • Abdominal pain
  • Constipation

Mounjaro Serious Side Effects

  • Thyroid cancer
  • Pancreatitis
  • Gallbladder disease
  • Kidney injury

Can You Take Wegovy and Mounjaro Together?

Wegovy and Mounjaro should not be taken together. They work in similar ways in the body, so taking these together could increase your chances of side effects and put you at risk for overdose. Mounjaro may be taken with other type 2 diabetes medications like metformin or insulin. If you’re taking Wegovy and are still not able to lose weight, talk to your healthcare provider about switching medications. 

Wegovy vs Mounjaro: Costs

Both Wegovy and Mounjaro are pricey prescriptions. Wegovy has a list price of $1,349 per month, and Mounjaro has a list price of Mounjaro $1,069 per month.8, 9 

You’re actual out of pocket costs will vary depending on your insurance plan. Neither drug has a therapeutically equivalent generic option, which drives up the price.  Both Novo Nordisk and Eli Lilly offer savings options and resources on their websites to make prescriptions more affordable. 

Learn More About How To Improve Blood Sugar Levels With Signos

Signos incorporates cutting-edge research and the proven power of continuous glucose monitoring to help you lose weight and improve your health. Not sure if Signos is right for you? Take this quiz to find out! Interested in learning more about nutrition and healthy eating habits? Check out more articles on our blog.

<p class="pro-tip"><strong>Learn More: </strong><a href="ozempic">Ozempic, Wegovy, and Mounjaro: What You Need To Know</a>.</p>

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About the author

Rebecca Washuta is a licensed dietitian with degrees in neuroscience and nutrition and helped individuals develop long-term health habits and achieve various wellness goals.

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