Unlike some familiar medications, Mounjaro is a little different when it comes to dosing. 

Mounjaro is designed to help you lose weight as part of a healthy lifestyle. It’s prescribed at a low starting dose, which you increase over time under your prescriber’s supervision, to make it safe for long-term use. 

Prescribers do this to help minimise side effects and maximise the weight loss benefits so you can enjoy continued weight loss success as your health journey continues. 

Let’s break down each phase of the Mounjaro weight loss treatment timeline and what you can expect along the way. 

Three key takeaways:  

• Mounjaro starts at a low dose which you gradually increase over time to reduce side effects and maximise weight loss. 

• Everyone’s timeline for weight loss on Mounjaro can be different. How quickly you increase your dose will depend on how well you tolerate the medication and your weight loss results. 

• Regularly checking in with your prescriber to monitor your results and side effects is key to long-term success on Mounjaro. 

Your Mounjaro timeline

If you’re taking Mounjaro to help you on your weight loss journey, your prescriber will start you on the lowest dose, with the aim of increasing the dose over time. This process is called ‘titration’.  

Starting at a lower dose and gradually strengthening the dose over time gives your body time to adjust to the medication’s effects, so you tolerate it better.  

This reduces your chances of experiencing side effects and makes any side effects that you do experience easier to manage. 

If you find that a lower dose suppresses your appetite enough for you to see weight loss results, you may not need to increase your Mounjaro dose each month. 

But if you do choose to increase your dose, and if you’re tolerating the medication well, a typical Mounjaro timeline looks like this: 

• Weeks 1-4: starting dose, 2.5mg 

• Weeks 5-8: increase to 5mg dose (if tolerated well) 

• Weeks 9-12: increase to 7.5mg dose, (if tolerated well) 

• Weeks 13-16: increase to 10mg dose, (if tolerated well) 

• Weeks 17-20: increase to 12.5mg dose, (if tolerated well) 

• Week 21 onwards: Maintenance dose of 15mg 

It’s important to note that your prescriber will only increase your dose if you’re tolerating Mounjaro well.  

Dose increases are based on your individual response to the medicine, as there’s no one-size-fits-all approach to titration. 

It’s crucial to make sure your side effects are manageable, and your body is responding well to the medication, so only increase your dose of Mounjaro under medical supervision. 

What affects your dosing schedule?

The dosing schedule for Mounjaro looks different for everyone and is based on several factors. 

Your dosing schedule will depend on: 

• how well you’re tolerating side effects 

• how much weight you’ve lost 

• any other medications you’re taking 

• whether you have any other health conditions  

Always listen to your doctor’s advice on dosing, they can advise you on when you’re ready to move up to a higher dose. 

Important safety considerations

It’s important to take Mounjaro under medical supervision. You should only increase the dose when your doctor agrees you’re ready to move up to a higher dose. 

Your doctor can monitor your side effects and how well you’re tolerating the medication. 

Some side effects may require medical attention, including: 

• severe pain in the stomach or back  

• gastrointestinal (digestive) issues  

• dehydration 

If you have a history of pancreatitis, or currently have gallstones, our pharmacists will not be able to prescribe you Mounjaro. If you develop either of these conditions while taking Mounjaro, we will not be able to continue prescribing it. 

Why can’t you start at the highest dose? 

Prescribers don’t start people on the highest dose due to the risk of severe side effects.

Starting at the lowest dose, rather than diving in at the deep end, gives you the chance to see how the medication affects you and lowers your risk of having severe side effects.

As a GLP-1 and GIP dual-action medication, Mounjaro also affects the way your body digests food, by slowing how quickly food leaves your stomach.

If you take too high a dose too quickly, your digestive system doesn’t have time to get used to this slower digestive transit.

This can make digestive side effects worse and lead to nausea and stomach discomfort, which can make it harder to tolerate the treatment and interfere with your weight loss journey.

Building up your Mounjaro dose slowly is both safer and more effective. 

Managing side effects during titration 

The titration process is designed to help make side effects more manageable. But you may find that side effects begin, return, or get worse when you titrate up to a higher dose. 

Just like on the lower doses, these side effects will reduce on their own over time as you get used to the higher dose of the medication.  

But there are steps you can take to make them more manageable in the meantime:  

1. Get ready for changing dose 

Since we know that increasing dose can potentially trigger or worsen side effects, it helps to be prepared for this possibility.  

Making sure you’re well-hydrated, sticking to your meal plan, and staying physically active will help you stay energized and feel your best as you move up to the next dose. 

2. Stay on the lookout for side effects coming back or starting 

When you change dose, side effects may start, or they may return.  

Be mindful of any changes you’re feeling, listen to your body, and make sure you have any medications handy that you’d usually use to manage side effects like diarrhoea and constipation. 

3. Go easy on yourself 

Titrating dose is a transition, and it can put a bit more stress on your body than usual as you get used to your new dose. 

So, if you need to take some downtime, give yourself permission to rest. Your body is adjusting, and it’s perfectly natural to need some you time to help you keep your energy levels up along your weight loss journey.  

If you’re still experiencing some side effects despite habit changes, you can also try familiar over-the-counter medicines like laxatives, pain relief medications, and antacids. 

Maintenance planning 

The maintenance phase of treatment is when the results of all your hard work are visible and the healthy habits you’ve been building as you’ve increased your dose are now locked in. This phase is all about keeping your success going! 

Remember, Mounjaro works best as part of a balanced, healthy lifestyle that focuses on diet, exercise, and a stable routine. Without these, you may end up regaining some of the weight you’ve lost. 

Maintenance dose 

The maintenance dose is the dose your prescriber will place you on once you’ve moved up through the lower doses, if you’re tolerating the medication well. 

This is to support long term weight loss and help prevent you regaining lost weight.  

The Mounjaro maintenance dose is whatever strength of Mounjaro helps you maintain your current weight. This will be decided between you and your prescriber.  

Frequently asked questions

How long does it take to reach maintenance dose on Mounjaro?  

If you’ve tolerated the lower doses well, prescribers typically recommend the 15mg maintenance dose from week 21 onwards.  

Can I lower my dose if side effects are too strong?  

Yes, your prescriber will review your current dose strength with you to assess how well you’re tolerating it. If side effects are an issue, you can always go back down to a loser dose until they resolve. 

How do I know if my dose is working?  

You’ll know your Mounjaro dose is working if you feel your appetite reduce and you’re seeing weight loss results. Typically, around 20% of your starting weight over 72 weeks. 

Will I stay on the same dose forever?  

Most people stay on each dose for at least 4 weeks as they build up to the 15mg maintenance dose. You can stay on this 15mg maintenance dose indefinitely if you’re tolerating the medication well. 

Sources:

• Mounjaro – Uses, How it Works and Side Effects (2025) Diabetes UK (Accessed 6 October 2025) 

• Tirzepatide (2025) NICE (Accessed 6 October 2025) 

• Tirzepatide for managing overweight and obesity (2025) NICE (Accessed 6 October 2025) 

• Tirzepatide as Compared with Semaglutide for the Treatment of Obesity  (2025) New England Journal of Medicine (Accessed 6 October 2025)