2 minute read

What to expect when taking Mounjaro for weight loss

By Nick Harland | Medically reviewed by Ruth Pointon
woman injecting weight loss medication mounjaro

Mounjaro is the latest weight loss medication to hit the UK market - and the evidence suggests it’s the most effective yet. The weekly injection works by regulating your appetite and reducing your food cravings to support healthy weight loss.

But sustainable weight loss that lasts - really lasts - takes time, and the changes you make to your lifestyle are just as important as the medication itself.

Here’s what you can expect from the Mounjaro treatment plan with Numan.

Eligibility and pre-consultation

Mounjaro is only prescribed to patients who are overweight or obese. A clinician will carry out an assessment and determine whether it’s a safe and effective treatment for you. They’ll ask you about your lifestyle, any medications you’re taking, and your treatment preferences.

If you’re prescribed Mounjaro through a Numan treatment plan then you’ll receive a monthly delivery containing a KwikPen, which is the device you’ll use to inject it. You’ll also receive alcohol wipes to clean the injection site and a sharps bin to dispose of needles.

Taking Mounjaro for the first time

Though some weight loss medication comes in the form of a tablet, Mounjaro is an injectable medication similar to Ozempic or Wegovy. You inject it yourself once a week, on the same day every week. Don’t worry if you forget - just make sure you take your dose within four days of your normal day. If it has been more than four days, skip this dose and wait until your next scheduled one.

Using the KwikPen, you either inject it into your stomach (at least 2 inches from your belly button) or in your upper legs on the front of your thighs. If someone else is helping you, they can inject it into your upper arm for you. You can inject Mounjaro in the same part of your body every week, although you should make sure it isn’t the exact same spot as before. 

You’ll receive full instructions on how to use Mounjaro when you receive your first delivery. Our clinical team will also be on-hand to support you through the treatment if you have any questions or queries.

Here’s what you can expect from Mounjaro month-by-month.

Month 1

  • Starting dose: 2.5mg

You’ll start your Mounjaro treatment plan on the lowest dose (2.5mg). If you’re responding well to the treatment, your clinician will gradually increase the strength of the dose over time. This is so that your body can get accustomed to the new medication and also reduce the chances of any side effects occurring.

The first month of your treatment is the time to get into the routine of taking Mounjaro, but also to start incorporating healthier habits into your lifestyle such as a more balanced diet and more active lifestyle. At Numan one of our health coaches will work with you to suggest lifestyle changes and ensure you’re working towards healthy, sustainable, long-term weight loss.

Although you may notice some changes to your appetite in the first month, you’re unlikely to experience much weight loss. This is a normal and healthy way to lose weight.

Month 2

  • Dose: 5mg

  • Expected weight loss: 6% body weight*

By the second month of treatment the eating habits of many patients should be noticeably different. You should be experiencing fewer food cravings, feel fuller for longer after meals and generally have a reduced appetite - particularly for sweet and high-fat foods.

If you don’t notice any changes to your appetite at this point then don’t worry - the medication affects everyone differently. It may just take a little longer to work for you.

You should also be starting to incorporate healthier habits into your lifestyle such as regular exercise, plenty of sleep, a balanced diet, and well-managed stress levels. As the treatment progresses these habits should become as natural to you as breathing in air.

Patients typically experience around 6% weight loss by the end of month two. 

Months 3-6

  • Dose: 7.5mg - 15mg

  • Expected weight loss: 9-11% body weight*

Between months 3 and 6 your dose will continue to increase as your body gets used to the medication.

Your dose will remain at 15mg from month six onwards. By now, you should see and feel visible changes in your weight. You should be following a balanced diet, living an active lifestyle, and in better control of your appetite.

After using Mounjaro for 18 months, patients can expect to lose around 21% of their starting body weight.*

*Based on tirzepatide 15mg over 72 weeks. Jastreboff, A. M., Aronne, L. J., Ahmad, N. N., Wharton, S., Connery, L., Alves, B., Kiyosue, A., Zhang, S., Liu, B., Bunck, M. C., Stefanski, A., & the SURMOUNT-1 Investigators. Tirzepatide once weekly for the treatment of obesity. The New England Journal of Medicine (2022)

Other things to bear in mind

Side effects

You may experience some side effects on Mounjaro, particularly when you first start taking it and when you increase your dose. The most common side effects are nausea, diarrhoea, and constipation. The Patient Information Leaflet included with your medication will contain a full list of reported side effects as well as how common each one is.


Ideally you should store the KwikPen in a fridge after its first use. However, as long as it’s stored at a temperature of less than 30°C then it’ll be perfectly safe to use.

Dispose of your pen six weeks after its first use or after it was first taken out of the fridge. You’ll receive a replacement in your monthly delivery.

Going on holiday

You don’t need to pause your treatment if you’re going away. Just make sure your Mounjaro pen is stored at a temperature of less than 30°C. If you’re worried it might go above that then you can store it in a coolbox instead. Remember to bring a copy of your prescription if you’re travelling abroad - airport staff may ask to see it.

The numan take

Get set for a weight transformation - but be patient. It may take some time to see results from Mounjaro as your body gets used to the medication. But you can expect to lose 21% of your body weight after 18 months. Combine the medication with positive changes to your lifestyle for weight loss that really lasts.