How Much Weight Can You Lose on Mounjaro in 3 Months?

If you’re considering starting medication to support your weight loss journey, it’s likely that you’ve already heard of Mounjaro and the impact it can have. However, weight loss injections are a big step, and you’ll inevitably have lots of questions about the medication to determine whether it’s right for you.

The efficacy of weight loss treatments is probably one of the most common queries people will have, both in the short and long term. After all, you’ll want to know whether the medication actually does what it’s supposed to.

So, with this in mind, just how much weight can you lose on Mounjaro in 3 months and beyond? Join us as we delve deep into the kind of results you could expect, so you can make an informed decision.  

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How Much Weight Can You Lose With Mounjaro?

Mounjaro is a dual agonist of both glucagon-like peptide-1 (GLP-1) and gastric inhibitory peptide (GIP) receptors, which means it mimics the actions of both hormones to promote effective weight loss. It is this dual action that can support users to lose, on average, 22.5% of their starting body weight after 68 weeks on the highest 15 mg per week dose.

Mounjaro is widely regarded as the most effective weight loss injection currently available. To illustrate this, a study comparing Mounjaro vs Wegovy found that the average weight loss after 3 months with Mounjaro was almost 6% compared to 3.6% with semaglutide (Wegovy). In further research, 98.5% of participants achieved at least a 5% reduction in weight with tirzepatide over 88 weeks, while 72% achieved at least a 20% weight loss within the same time frame.  

How Long Until Mounjaro Works?

Mounjaro starts to work almost straight away after your first injection, with some people noticing a reduction in their appetite within a week. However, the rate at which Mounjaro works will vary from person to person. Some people have lost around 2.5 kg in the first five weeks of taking the highest dose of tirzepatide, Mounjaro’s active ingredient.

Remember, though, that you will not reach your highest strength until at least week 21 of treatment. Therefore, it is essential to recognise that safe and sustainable weight loss is a gradual process that also requires healthier lifestyle habits alongside the use of Mounjaro. 

How Much Weight Can You Lose on Mounjaro in 3 Months?

How much weight you can lose on Mounjaro in 3 months will depend on several factors, including your lifestyle, the dosage, and how well your body responds to the treatment. One study found that after 12 weeks on 5, 10, or 15 mg of tirzepatide, the average weight loss was approximately 8%. The results of this trial are summarised in the table below:

A further study comparing the effects of tirzepatide and semaglutide found that those on Mounjaro achieved a greater weight loss within 3 months (2.3%) compared to those on Wegovy.

However, this is just an average, so you may lose more or less than this in the first 3 months of Mounjaro treatment. Generally, if you have not lost at least 5% of your starting body weight after 6 months with Mounjaro, a clinician may recommend trying an alternative weight loss medication. 

Now that we've provided a brief glimpse of potential results, let's look deeper into the question “how much weight can you lose on Mounjaro in 3 months”. 

Mounjaro Results After 1 Month

Studies show that the average weight loss on Mounjaro after one month is around 4%. However, this can vary from person to person, and at this time, you will have only been on the lowest 2.5 mg dose of Mounjaro. So, even if you haven’t noticed significant changes to your weight, look out for signs like a reduced appetite and fewer cravings.

There is no set amount of weight you should lose week by week on Mounjaro, but continuing to make healthy lifestyle changes, such as reducing your calorie intake and increasing your exercise output, will enhance Mounjaro’s effectiveness.

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• Approved Weight Loss Treatment
• Suitable for adults with a BMI of +30kg/m²
• Pre-filled injection pen

• Discreet delivery next working day
• Online prescription - No doctor visit

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How Much Weight Can I Lose on Mounjaro in Two Months? 

After two months on Mounjaro, your dose will increase to 5mg, which may help you lose up to 6% of your starting body weight, provided you follow the recommended lifestyle changes, such as a reduced-calorie diet and regular physical activity.

The amount you will lose during this time depends on factors including your starting BMI, age, sex, any underlying health conditions, and how well you adhere to the healthy lifestyle changes recommended for you. Recognising that these factors will make your journey unique and different from others', it will be easier to focus on your journey and stick to your new, healthy habits. 

Mounjaro Results: 3 Months In

After 12 weeks, if you have followed the Mounjaro dosage schedule, you should be taking 7.5mg per week, which can lead to an average weight loss of 8%. At this point, sticking to your new healthy habits should become easier, making the weight loss process less of a struggle and more of a lifestyle.

Don’t worry if your results are different from those reported in clinical trials. Often, these results are based on averages, and each person will react differently to Mounjaro. Your weight loss journey is unique to you. So, it is essential to be patient with yourself and your body, because stress can also negatively impact your progress.

It’s also important to note that after three months, you will still not have reached the maximum maintenance dose of 15mg per week, which is the most effective strength. Therefore, it’s crucial to stick to the dosage schedule as closely as possible and allow Mounjaro time to take its full effect.   

How to Make Mounjaro More Effective

Mounjaro can be made more effective through several lifestyle modifications, including a balanced diet, regular exercise, adequate sleep, and effective stress management. Here are some of our top Mounjaro tips and tricks to help you get the most out of this weight loss medication and yield success:

• Diet: Weight loss medications are most effective when combined with a modified diet that promotes healthier and more balanced eating habits. Use our 7-day diet plan guide to help you create suitable meals that support your weight loss goals.  
  Exercise – Mounjaro and exercise go hand in hand. By increasing your physical activity, your body will burn more calories, thereby increasing your calorie deficit and helping you shed pounds. Research also shows that exercise can help you sustain weight loss even after your treatment has ended. 
• Sleep and stress management: Poor sleep and stress can lead to hormone imbalances, which can contribute to weight gain and make it harder to lose weight. Therefore, it is crucial to promote good sleep by establishing routines and practising good sleep hygiene, as well as utilising mindfulness, meditation, and breathing exercises to counteract stress. 
• Hydration: Aim to drink 6 to 8 glasses of water per day to help curb cravings and prevent side effects, like constipation. 
• Follow the dosage schedule: Where possible, adhere to the dosage schedule for optimal results. It has been designed to help you titrate up gradually, limiting side effects and supporting gradual and consistent weight loss. However, if you are satisfied with your progress on a specific dose or are experiencing side effects, discuss with your clinician the option of sticking to a lower strength for a longer period.

Mounjaro

Rated 0 out of 5 based on 0 reviews

Rated 0 out of 5 based on 0 reviews

• Approved Weight Loss Treatment
• Suitable for adults with a BMI of +30kg/m²
• Pre-filled injection pen

• Discreet delivery next working day
• Online prescription - No doctor visit

Prices from £159.99 Review More Prices

Start Order More Info

Get Started

Start Order More info

How Long Can I Stay on Mounjaro?

Mounjaro is approved for long-term use and can be taken indefinitely, or until you reach your weight loss goals. Our clinician will regularly review your progress and adjust or stop treatment if needed. Always follow the advice of our clinicians for ongoing use. If you have any concerns, speak with them for further guidance.

Frequently Asked Questions

Considering Mounjaro for weight loss? If you're wondering how much weight you can lose on Mounjaro in 3 months, you're not alone. Starting any weight loss injection is a big decision, and it’s important to understand what to expect. Below, we’ve answered common questions to help you make an informed choice.

How Does Mounjaro Dosage Work?

Mounjaro is started at a low dose to help your body adjust and reduce side effects. The starting dose is 2.5 mg once weekly, with gradual increases every four weeks based on your tolerance and treatment goals. The maximum dose is 15 mg weekly, typically achieved after 21 weeks of treatment if the Mounjaro dosage schedule is followed correctly.

Our clinicians will guide you through this step-by-step titration schedule, adjusting the dose as needed to balance results with tolerability. This gradual increase helps improve effectiveness while minimising side effects such as nausea or digestive upset. For more information on how Mounjaro dosage works, refer to our comprehensive guide. 

Is Mounjaro or Wegovy More Effective?

Clinical trial results indicate that Mounjaro is more effective than Wegovy in promoting weight loss. The SURMOUNT-5 trial found that the average weight loss with Mounjaro was 20.2% compared to 13.7% with Wegovy. However, that does not mean it will be the best option for you, and it’s also essential to compare Mounjaro vs Wegovy for yourself.

Our clinician can help you switch from Wegovy to Mounjaro, or vice versa, if you feel it would be a more suitable option for you.  

Does Mounjaro Have Side Effects?

Yes, common Mounjaro side effects include feeling sick (nausea), being sick (vomiting), diarrhoea, and constipation. How long Mounjaro side effects last depends on several factors, but they are usually mild and should improve as your body becomes accustomed to the medication. However, in rare cases, Mounjaro can cause more serious side effects, such as severe allergic reactions and pancreatitis.

If you experience severe stomach and back pain that does not go away, you should see a doctor straight away. If you are struggling to breathe, your face, lips, tongue, or throat swells, or you have a rapid heartbeat, this is a medical emergency and you should call 999 or go to A&E.

Prescription Doctor: Your Reliable Weight Loss Partner

Making the decision to start Mounjaro, or any other medication, and change your lifestyle to lose weight can be daunting, and one that you won’t want to make alone. At Prescription Doctor, our clinicians are available to help you choose the right weight loss medication for you. As well as answering the question “how much weight can you lose on Mounjaro in 3 months”, we can also help with managing side effects, advising on the correct dosage, and everything else you need to support your weight loss journey. 

Our online weight loss consultation service allows you to access medication from the comfort of your own home. There are no lengthy waiting lists, and you can be assured that our General Pharmaceutical Council (GPhC) registered service will safely supply genuine medication. So, choose Prescription Doctor for a seamless and speedy weight loss service and start your Mounjaro consultation today.  

Authored By

Leanne Edermaniger

Medical Content Writer

Leanne is a science and health content writer focusing on human health and biology while utilising her solid academic background.

Published on: 06/08/2024 Re-Published on: 21/07/2025

Reviewed By

Mohamed Imran Lakhi

MPharm - Lead Pharmacist

Imran Lakhi is the superintendent pharmacist and founder at Prescription Doctor. He has been at the core of our team.

Reviewed on: 21/07/2025