Not losing weight on Mounjaro? 6 reasons why

Key Points

• There may be many reasons why you’re not losing weight on Mounjaro, including medication dose, diet, physical activity, emotional eating triggers, other drugs, and more
• Meds like Mounjaro work better when paired with a healthy diet and moderate exercise
• Everyone responds differently to weight loss. A registered dietitian can develop a custom, personalized weight-loss diet plan that works for you

You’ve started Mounjaro to manage type 2 diabetes, and maybe you’ve heard people raving about the weight loss that comes with it. But weeks have passed, and your scale hasn't budged. It can be quite frustrating.

The truth is, while Mounjaro can kickstart weight loss for many people, results vary wildly from person to person. Some drop pounds quickly, while others see minimal changes despite doing everything "right."

Let's dig into the reasons why Mounjaro might not be delivering the results you hoped for. Plus, nationally-recognized Registered Dietitian Lyla Joffe, MS, RD, offers expert advice on what to do when you’re not losing weight on Mounjaro.

What is Mounjaro (tirzepatide)?

Mounjaro is a medication authorized by the US FDA for adults with type 2 diabetes. When used together with diet and exercise, it helps improve blood sugar (glucose) control in people living with insulin resistance.

Mounjaro is not approved for weight loss, but its main ingredient, tirzepatide, is approved for weight loss under the name Zepbound.

So, if you're not losing weight while taking Mounjaro, don't worry. A few adjustments may be needed to your medication, lifestyle, or expectations to help get things moving.

Let's explore the reasons why your weight loss journey with Mounjaro might be different than expected.

How does Mounjaro work?

Tirzepatide works by mimicking two important hormones in your body: GLP-1 and GIP.  These hormones control your hunger signals, how quickly you digest food, and how your body manages blood sugar.

Here’s how these hormones help:

• GLP-1 (Glucagon-like Peptide-1): This hormone slows down digestion, reduces your appetite, and helps your body produce insulin to manage blood sugar levels.
• GIP (Glucose-Dependent Insulinotropic Polypeptide): This natural hormone helps your body process sugar more effectively and works together with GLP-1 to control blood sugar levels.

Understanding how Mounjaro affects your body is important, but you're probably wondering about the results you can expect—specifically when it comes to weight loss.

How much weight can you lose on Mounjaro?

While Mounjaro is not indicated for weight loss, people on Mounjaro do experience weight loss.

In a study of over 2,500 adults with obesity, people taking tirzepatide lost an average of 15% to 20% of their body weight after about a year and a half.

If you're taking Mounjaro or another diabetes weight loss drug, you might be hoping to see some weight loss along with better blood sugar control. While weight loss may be possible, it's important to have realistic expectations. Remember that results can vary significantly from person to person.

Registered Dietitian Lyla Joffe, RD says, "Sustainable weight loss is not achieved overnight. If we lose weight too quickly, we risk nutrient deficiency, bone density loss, and muscle wasting. Although weight loss is a fair goal, the ultimate goal is to be healthy. Just like the weight did not come on overnight, neither will it come off overnight. A healthy rate of weight loss is 1-2 pounds per week, and the journey isn't always a straight line. Stay patient and consistent with your lifestyle changes, and you will reach your goals."

If you aren't seeing the weight loss results you were hoping for, don't get discouraged. Let's look at some common reasons why you might not be losing weight on Mounjaro and what you can do about it.

6 reasons why you’re not losing weight on Mounjaro

1. Diet still matters

While Mounjaro helps lower your appetite, what you eat remains essential for weight loss. Clinical trials confirm that people on tirzepatide achieved better results when combining the medication with healthy lifestyle changes.

Ultraprocessed foods, sugary items, and large portions can undermine your progress despite Mounjaro's benefits. Restaurant meals often contain hidden calories from cooking oils and butter, even in seemingly healthy options.

“Weight loss is multifaceted. Sleep, stress & exercise impact the secretion of hunger hormones and dictate our cravings. In order to be successful, we must look at the journey holistically,” says Joffe, RD. “Instead of opting for crash diets, think about changes you can sustain lifelong. When it comes to nutrition, it is all about quality over quantity. If a diet is rich in processed foods, they will not be efficiently metabolized and can encourage inflammation. Focus on single-ingredient whole foods to decrease inflammation and increase satiety.”

Consider whole, nutrient-rich foods:

• Fresh fruits and vegetables
• Whole grains
• Lean proteins
• Healthy fats

Foods high in added sugars, saturated fats, and sodium can counteract your weight loss efforts even while taking Mounjaro. Consider working with a weight loss dietitian to create an eating plan that maximizes the medication's effectiveness and supports your goals.

2. Emotional eating triggers

Using food to cope with emotions is more common than you might think. Whether it's reaching for ice cream after a stressful day or snacking on chips when you're bored, many of us turn to food for comfort. This pattern often develops early in life when food becomes linked with feeling better during tough times or as a "treat."

There's nothing wrong with enjoying a variety of foods. However, if strong urges to eat non-nutritious foods become roadblocks to your health goals, don't get disheartened. Learning to stop food cravings isn't simply about willpower—these are complex emotional patterns years in the making.

Some ways to help with emotional eating urges include going for a walk, calling a friend, or writing in a journal instead of turning to food. Consider eating mindfully by focusing on your meal without distractions like TV or your phone.

If emotional eating or binge eating affects your progress despite your best efforts, consider working with a mental health counselor who can help you develop strategies to help you manage your emotions without relying on food.

3. Lack of physical activity

Exercise plays an important role, even when you’re taking Mounjaro or other GLP-1 drugs. While the medication helps control your appetite, adding regular movement can enhance your results.

Physical activity doesn't have to mean intense workouts—even moderate activities like brisk walking make a difference. The US CDC recommends 150 minutes of moderate exercise each week, which breaks down to just 30 minutes five days a week.

Plus, consider adding strength training twice a week. This helps increase muscle mass while you lose weight, which keeps your metabolism running efficiently.

When you combine regular movement with your healthy eating habits, you're more likely to see better results from your medication. If you're new to exercise, talk to your healthcare provider about activities that are right for you.

4. Give your meds a little time to work

Mounjaro takes time to reach its full effect in your system. Your body needs an adjustment period, just like with any new treatment.

In the first couple of months, you might notice some weight changes, but everyone responds differently. Some people see results sooner, while others take longer. What matters most is staying consistent with your medication schedule and healthy habits.

This early period is important as your body adapts to the medication. If you're not seeing changes right away, know that this is completely normal and part of the process for many people.

5. Find your optimal dose

In trials, participants taking 5 mg lost about 16% of their starting weight, while those on 10 mg lost 21%, and people on 15 mg lost 22.5%. Getting started on Mounjaro is a gradual approach. Your doctor typically starts at a lower 2.5 mg weekly dose to help your body adjust and minimize discomfort.

Over time, your provider may increase your dose in small doses tailored to how your body responds to the medication.

Note: It’s very important not to make any changes to your dosage without speaking with your healthcare provider. They can evaluate your dosage while prioritizing your safety.

6. Effect of other medication on weight loss

If you're not seeing the expected results with Mounjaro, your other medications or health conditions might play a role. Some medications, like those for blood pressure, mental health, or hormonal treatments, can affect how your body responds to Mounjaro.

This doesn't mean you should stop taking any of your medications. Instead, talk to your healthcare provider if you're concerned about your progress. They can review all your medications and health conditions to see if adjustments might help improve your results with Mounjaro.

Sometimes, simple changes to when you take your medications or slight adjustments to your doses can make a difference.

Final Thoughts: Losing weight on Mounjaro

Living with type 2 diabetes and managing your weight on Mounjaro is a unique journey for everyone. While the medication can be an effective tool, remember that sustainable results come from a combination of factors—your medication, diet choices, physical activity level, and emotional well-being all work together.

If you're not seeing the weight loss you hoped for, don't be discouraged. Speak with your healthcare provider about adjusting your dose or approach. Consider consulting with specialists like registered dietitians who can provide personalized support for your specific challenges.

Most importantly, be patient with yourself. Your body may need time to respond, and setbacks are a normal part of any health journey. Focus on the positive changes you're making for your overall health, not just the number on the scale.

Find a registered dietitian to help you lose weight on Mounjaro (tirzepatide), covered by your insurance.

Frequently Asked Questions (FAQs)

How fast can I lose weight on Mounjaro?

Mounjaro is FDA-approved for managing type 2 diabetes, not specifically for weight loss. However, weight changes are a common effect of the medication.

Research shows that people combining Mounjaro with healthy eating and regular exercise typically experience gradual results over months, not weeks. Studies found weight reductions of approximately 15% to 20% over 72 weeks (about a year and a half), though individual results vary significantly.

Joffe, RD says, “Work with your healthcare provider to set realistic expectations based on your specific situation and health goals. A healthy rate of weight loss is generally 1-2 pounds per week, creating a more sustainable approach to long-term success.”

How to speed up weight loss on Mounjaro?

While it's natural to want faster results, steady, sustainable changes work best.

Research shows the power of combining Mounjaro with healthy habits. A study found that people who added lifestyle changes to their medication lost an additional 21% of their body weight in just 12 weeks. Over about a year and a half, participants had lost approximately 27% of their starting weight.

To help your body respond better to Mounjaro:

Focus on eating a diabetes-friendly diet. Build your meals around whole foods—colorful vegetables, lean proteins, fiber-rich whole grains, and heart-healthy fats. Skip the processed foods and sugary drinks that can derail your progress.

Stay active in ways you enjoy. This doesn't mean intense workouts—even regular walks or activities you like can make a difference. Consistency matters more than intensity.

Maintain daily habits. Take your medication as prescribed, eat regular meals, and follow a routine. Small, steady changes often lead to better long-term results than rushing the process.

Mounjaro vs. Zepbound: What's the difference?

Mounjaro and Zepbound contain the same active ingredient, tirzepatide—they're simply different brand names for the same medication. The key difference is what the FDA has officially approved each brand to treat.

Mounjaro was approved first specifically to help manage type 2 diabetes. Though some doctors prescribe it "off-label" for weight loss, that's not its FDA-approved purpose.

Zepbound came later with FDA approval specifically for weight management in adults with obesity or who are overweight with certain health conditions. Recently, it received additional FDA approval for people with obstructive sleep apnea.

Both medications:

• Have the same active ingredient, tirzepatide
• Come from the same company (Eli Lilly)
• Require one injection weekly
• Work by controlling appetite and slowing digestion

Start losing weight today. Find a weight loss dietitian who accepts your insurance.

The views expressed by authors and contributors of such content are not endorsed or approved by Fay and are intended for informational purposes only. The content is reviewed by Fay only to confirm educational value and audience interest. You are encouraged to discuss any questions that you may have about your health with a healthcare provider.