Why Am I Not Losing Weight on Mounjaro® (Tirzepatide)?
Key takeaways:
Mounjaro® (tirzepatide) can support significant weight loss, but results vary.
Progress may stall due to your dose, eating habits, lifestyle, or medical conditions.
A calorie deficit, a balanced diet, and regular exercise (including strength training) are essential to weight loss with Mounjaro®.
If you’re not losing weight, your GP or private provider can adjust your treatment plan or suggest alternatives.
If you’ve been taking Mounjaro® (tirzepatide) and aren’t seeing the weight loss results you want, you probably have questions. You may wonder if it’s the particular medication or dose you’re on, if you’re taking it correctly, or if you’re making the right lifestyle changes to support weight loss.
Why am I not losing weight on Mounjaro®? There are several reasonable explanations as to why you aren’t losing the weight you’d hoped. And there are plenty of solutions that can help support your weight loss journey.
Keep reading for insight.
Why Am I Not Losing Weight on Mounjaro®?
If you’ve been prescribed Mounjaro® for weight management but the scales aren’t shifting the way you expected, you’re not alone. Many people ask the same question: Why am I not losing weight on Mounjaro®?
There are several possible reasons, from your current dose to your eating habits and lifestyle changes. And there are just as many solutions to help get you back on track with weight loss.
We’ll explore some of the common reasons why you might not be losing weight on Mounjaro®.
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How Mounjaro® Works
Before discussing why Mounjaro® might not work for you, it’s important to understand how the medication is meant to work.
Mounjaro® is a weekly weight loss injection. In the United Kingdom, the Medicines and Healthcare products Regulatory Agency (MHRA) has authorised Mounjaro® for the treatment of obesity and type 2 diabetes.
This medication contains the active ingredient tirzepatide. Tirzepatide acts on two brain receptors involved in appetite control, GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide). As a result, the medication:
Slows how quickly your stomach empties
Reduces your appetite
Increases feelings of fullness
Regulates blood sugar levels
This typically helps you eat fewer calories, leading to weight loss.
Research shows that tirzepatide can promote weight loss in people with or without type 2 diabetes.
Why Am I Not Losing Weight on Mounjaro®? 6 Possible Reasons
Here are six possible explanations for why you’re not losing weight on Mounjaro®.
Reason 1: Mounjaro® Isn’t Right for You
If you aren’t losing weight on Mounjaro®, you may have better results using different weight loss medicines. For instance, there’s Wegovy® (semaglutide), a weekly GLP-1 injection, and Saxenda® (liraglutide), a daily GLP-1 injection.
Some research suggests that Mounjaro® may be more effective than Ozempic® when it comes to weight loss in patients with type 2 diabetes.
But everyone’s body is different. If you’re not losing weight, it’s possible a different GLP-1 will work better for you.
Reason 2: You Need a Different Dose
Medical providers usually start patients on lower doses to minimise side effects like constipation or nausea. Over time, the side effects of Mounjaro® generally improve. At that point, your provider will recommend gradually increasing your dose.
Studies show that higher doses of tirzepatide can lead to more significant weight loss, particularly for those with type 2 diabetes.
Here’s how it went in one clinical trial:
Participants who took 5 mg (milligrams) of tirzepatide weekly lost an average of 15 percent of their starting body weight over 72 weeks.
In the same amount of time, those on a 10-mg dose lost about 19.5 percent of their starting weight.
Study participants who took 15 mg of tirzepatide lost 21 percent of their starting weight.
A 2025 review of trials also concluded that higher doses of tirzepatide led to more weight loss. Higher doses were also associated with worse side effects, though.
If you’re not losing weight on Mounjaro®, your general practitioner (GP) or private healthcare provider might suggest a higher dose. But it’s crucial not to increase your dose too quickly. Switching to a higher dose before your body adjusts to the medicine could result in worse side effects. A slow, gradual increase is best.
Never increase your dosage without your provider’s say-so.
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Reason 3: You Need to Change Your Diet
Mounjaro® and other weight loss injections can be highly effective. But they’re not a silver bullet, and they don’t replace a healthy diet.
One reason Mounjaro® helps promote weight loss is that it helps you eat less. By reducing cravings and appetite, it helps you stick to a low-calorie diet. When you eat fewer calories than you burn each day, you’re in a calorie deficit. This makes it possible to lose weight.
Your healthcare provider can help you figure out how many daily calories to eat to lose weight. Generally, the National Health Service (NHS) recommends reducing your daily calorie intake by about 600 calories to lose weight.
This means a daily allowance of about 1,900 calories for men and 1,400 for women.
It’s not just how much you eat that matters but also what you eat. To ensure you get all your nutrients without eating too many calories, eat a balanced diet consisting of:
Whole foods, such as vegetables, fruit, beans, and whole grains
Healthy fats like olive oil, nuts, and seeds
Lean proteins to preserve muscle mass
Complex carbohydrates, in moderation
You might find a calorie tracker or food diary helpful to monitor your food intake. This can help you stick to healthy eating habits while staying in a calorie deficit.
Reason 4: You Need More Exercise
When it comes to fat loss, regular exercise is another vital component you shouldn’t overlook.
Regular physical activity helps support weight loss by:
Burning more calories. Exercise burns calories, making it easier to stay in a calorie deficit.
Reducing stress. Stress hormones can interfere with gut hormones and appetite control, making weight loss harder.
Promoting sleep quality. Poor sleep can interfere with hunger hormones, which makes it harder to eat a healthy diet.
Building muscle. If you’re on tirzepatide, you likely want to lose fat, not muscle. When you gain muscle, you’ll look slimmer and feel stronger. Plus, it benefits your metabolism.
For best results, do a mixture of cardio and strength training. This will help you preserve muscle mass while losing weight.
If you find it hard to stick to an exercise plan, consider activities you enjoy, like walking, swimming, or group classes. Pairing up with a friend can help keep you accountable and make workouts feel less like a chore.
The NHS has a number of free resources to help you get more active.
Reason 5: You Need More Time
Like any other weight loss medication, Mounjaro® doesn’t work overnight.
We get it — you’re probably excited to lose weight. But if you expect to reach your weight loss goal within a few months, you might need to adjust your expectations.
Some people take longer to respond to tirzepatide. Others experience weight loss plateaus, when weight loss stalls after you initially lose weight.
Although this can be frustrating, patience is key. Keep consistently taking your medication, exercising regularly, and eating well, and you’ll likely break through the plateau.
Many studies on tirzepatide show that people lose 15 to 20 percent of their starting weight if they take the medication for over a year. While everybody is different, this highlights that Mounjaro® isn’t a quick fix but rather a medication that works gradually.
Reason 6: You’re Gaining Muscle
If you started strength training when you started Mounjaro®, cheers to you. Strength training is a great way to take care of your physical and mental health.
However, if you’re gaining muscle, the scale might not move as quickly. If you lose fat and gain muscle, you’ll look more trim, but your weight might not change that much.
That’s why the number on the scales shouldn’t be your only measure of success. Pay attention to how your clothes fit, track your energy levels, and celebrate improvements in your overall fitness and strength.
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Why Am I Not Losing Weight on Mounjaro®? The Bottom Line
Mounjaro® can be a powerful tool in weight loss treatments, but it’s not a cure-all or an overnight fix. Here’s what to bear in mind if you’re not losing weight on tirzepatide:
A number of factors might be at play. You might need a different dose, a different GLP-1 medication, or more time to reach your weight loss goals.
Mounjaro® works best when paired with a healthy lifestyle. To aid weight loss, eat a healthy diet low in calories, and exercise regularly.
Speak with an expert. If your weight loss stalls, your GP or private healthcare provider might adjust your treatment plan, review your diet and exercise routine, or consider alternatives.
As with all prescription medications, if you are unsatisfied with how Mounjaro® is working, speak with your healthcare provider. They can offer you support and assistance.
Ready to begin your weight loss journey? Hers U.K. can connect you with a U.K.-licensed medical professional so you can access the help you need.
FAQs
See answer to common questions about not losing weight on Mounjaro®.
Why am I not losing weight on Mounjaro® 5 mg?
It may be that you’re on the wrong dosage and that you’ll lose weight when your dose increases. Or it could be that Mounjaro® simply isn’t right for you. You may also need to adjust your exercise routine or diet plan.
Does Mounjaro® work for everyone?
Clinical trials show that Mounjaro® is effective for most people — but not all. If it doesn’t work for you, alternatives like Wegovy® or Saxenda® may help.
What if I have side effects on Mounjaro®?
Common side effects of Mounjaro® include nausea, constipation, and upset stomach. These issues usually go away after the first few weeks. Speak with your provider if the side effects affect your weight loss efforts or daily activities.
How can I improve my weight loss on Mounjaro®?
Engage in healthy habits. Exercise frequently, eat a healthy diet, and stay hydrated. Maintaining a calorie deficit is important for weight loss, so aim for smaller portion sizes and avoid high-calorie processed foods.
This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your GP about the risks and benefits of any treatment.