Mounjaro is a type of medication you might need to take if you have type 2 diabetes.
- What is Mounjaro used for?
- How does Mounjaro work?
- Is Mounjaro available across the UK?
- Who can take Mounjaro?
- How is Mounjaro taken?
- Your Mounjaro prescription
- Mounjaro side effects
- More information and support with Mounjaro
What is Mounjaro used for?
Mounjaro, the brand name for tirzepatide, is a treatment for type 2 diabetes. It can also be prescribed to support people with weight loss.
How does Mounjaro work?
This medication works by activating two receptors called GLP-1 and GIP to increase the level of incretins – hormones - in the body.
It works by helping your body to produce more insulin when needed. It also reduces the amount of glucose, or sugar, produced by the liver, and slows down how quickly food is digested. This all helps to lower blood sugar levels and HbA1c.
Mounjaro can also lead to weight loss. This is because it slows down how quickly food is digested. This means it can help you stay full for longer, which can lead to weight loss.
Is Mounjaro available across the UK?
Yes, for treating type 2 diabetes and for treating obesity.
Mounjaro was approved by the National Institute for Health and Care Excellence, or NICE for short, for treating obesity on the NHS in December 2024 and is now available within specialist weight management services in England and for some people via their GPs.
As of June 2025, people with the greatest clinical need for treatment should be able to access Mounjaro for obesity via their GP services in England. This prioritisation is based on an individual’s BMI and the number of weight-related health conditions (including type 2 diabetes) they have.
The Scottish Medicines Consortium, or SMC for short, has also approved the use of Mounjaro to treat type 2 diabetes and for treating obesity, though the criteria are slightly different in Scotland.
Who can take Mounjaro?
Treatment for type 2 diabetes
Adults aged 18 and over with type 2 diabetes can take Mounjaro.
New guidelines from the National Institute for Health and Care Excellence, or NICE for short, recommend earlier use of GLP-1 medications for some groups of people. You’re more likely to be offered a GLP-1 such as Mounjaro if you’re an adult with type 2 diabetes and:
- You were diagnosed before the age of 40
- Are living with obesity.
Your healthcare team will discuss your options to decide if this treatment is right for you based on your individual needs and circumstances. If you think that you would benefit from taking Mounjaro to manage your type 2 diabetes speak with your healthcare team so that you can make an informed decision together about your treatment.
NICE guidelines are used in England and Wales and tend to be endorsed and adopted in Northern Ireland. If you live in Scotland, care may be based on SIGN guidelines. Please speak to your healthcare team if you have any questions or concerns about your treatment.
Treatment for weight loss
In December 2024, NICE recommended Mounjaro for use as a medication for weight loss on the NHS in England and Wales when someone has a BMI of at least 35kg/m², and they have additional medical conditions that are related to obesity, including type 2 diabetes and other weight-related conditions.
Mounjaro is also available as a medication for weight loss within the NHS in Scotland, where it was approved by the SMC for people with a BMI of at least 30kg/m², and one additional medical condition that is related to obesity.
Under the NICE and SMC recommendations, a lower BMI applies to people from Black African, African-Caribbean, Asian, South Asian, Chinese, and Middle Eastern backgrounds who have additional medical conditions that are related to obesity.
Normally in England, NHS England has three months after a NICE decision to make a new drug available to those who are eligible, but due to the associated high costs and current lack of support services, they are gradually rolling it out over a 12-year period for the eligible population in England.
As of June 2025, people with the greatest clinical need for treatment will be able to access Mounjaro for obesity via their GP services in England. This prioritisation is based on an individual’s BMI and the number of weight-related health conditions (including type 2 diabetes) they have.
This means that you are currently unlikely to be prescribed Mounjaro for weight loss on the NHS unless your BMI is over 40 and you have four weight-related conditions. The implementation plan will mean that 220,000 people living with obesity will be taking Mounjaro within a three-year period.
In Scotland, weight loss medications are being phased in based on clinical need, starting with people who have a BMI over 38kg/m² and one related health condition.
Who can’t take Mounjaro?
Some medications might not be suitable for some people, which might be because of medical conditions or other reasons. The list below shows some of the reasons why Mounjaro might not be a suitable treatment for you:
- You might not be able to take Mounjaro if you have severe problems with your digestion. You might also need to temporarily stop taking Mounjaro if you’re going to have an operation;
- If you’ve had pancreatitis before, Mounjaro might not be suitable for you. Your doctor will tell you to stop taking this medication if you have pancreatitis;
- You should not take this medication if you are pregnant. Speak to your healthcare professional for advice before taking Mounjaro if you are breastfeeding or planning a pregnancy.
The patient information leaflet that comes with the medication will have an up to date list of warnings and precautions. When you start a new medication, always check with your healthcare team that it’s suitable for you to take. You can discuss any other medical conditions you have and any other medications you are taking.
It is important that the healthcare professional prescribing Mounjaro is aware of your full medical history, including your type of diabetes, and accurate body weight.
How is Mounjaro taken?
Mounjaro is an injection that you take once a week. Your healthcare team will give you more information about how to take it and how to inject. Make sure you are rotating your injection site to avoid skin problems.
There are different types of injections that you can use to take Mounjaro. You can take it through a one-dose pen or a multi-dose pen called the Mounjaro Kwikpen. Although Mounjaro is given via injection, it is a different medication to insulin.
The Mounjaro Kwikpen comes as a four-dose pre-filled injection pen, which you take at a starting dose of 2.5mg once a week for four weeks.
After taking the starting dose for the first four weeks, the dosage will increase every four weeks until you are taking the dose that is effective for you, up to the maximum dose of 15mg. Mounjaro KwikPens, containing four doses per pen, are now available in each different strength from 2.5mg up to 15mg.
This means your prescription will change every four weeks until you are on the right dose for you, but you’ll still only have to take 1 injection per week – so it’s important to check you have been given the right strength pen for your current dose. Always take this medication exactly as your healthcare team has told you. The Patient Information Leaflet inside the box will tell you how to take it but always check with a doctor or pharmacist if you are not sure.
Your Mounjaro prescription
You may choose to access Mounjaro for weight loss via private prescription. It is important that your prescriber completes the same assessment that an NHS healthcare team would carry out. This includes checking your medical history and body weight. This is to ensure Mounjaro is the right medication for you and that it is safe.
You should only be given a prescription for Mounjaro following an assessment by your healthcare team to make sure that you meet the criteria and that you’ll benefit from its use.
You should only be given a prescription for Mounjaro following an assessment by your healthcare team to make sure that you meet the criteria and that you’ll benefit from its use.
This should be an individual assessment that includes how Mounjaro will fit into your current treatment plan and considers any diet or activity programme that you are following, as well as the risk of side effects, the dose you’ll need, and your personal choices.
Your healthcare team should explain your prescription to you but it's important to make sure you ask if you don't feel you know enough.
And make sure you talk to your GP or your diabetes team if you struggle to take Mounjaro. They might be able to help by giving you a different dose.
In England, if you need to take any medication to manage your diabetes, your prescriptions will be free. Ask your healthcare team about a prescription exemption certificate if you don't have one, to make sure you don't get charged for your medication. Prescriptions are already free for everybody in the rest of the UK, so you shouldn't pay for your medication.
Mounjaro side effects
Common side effects of Mounjaro can include:
- feeling sick (nausea)
- being sick (vomiting)
- diarrhoea
- stomach pain
- constipation
- risk of low blood sugar
Risk of low blood sugar
When taken on its own, Mounjaro does not usually cause blood sugar levels to become too low, also called hypoglycaemia or hypos. However, hypos are more likely to happen when you take it with other diabetes medications such as insulin or a sulphonylurea.
Your healthcare team may advise reducing the dose of your sulphonylurea or insulin medicine when you start taking Mounjaro to reduce the risk of hypos.
Risk of high blood sugar
If you take Mounjaro with insulin, and your insulin is reduced too quickly, it can cause high blood sugar levels; this is called hyperglycaemia, and there is an increased risk of diabetic ketoacidosis, also called DKA. Your healthcare team should discuss with you the signs and symptoms of DKA.
And you should have a plan for when you are unwell, which is also known as sick day rules.
Risk of worsening retinopathy
If you have diabetic eye disease, known as diabetic retinopathy, and you're using insulin, then your retinopathy could get worse when you start Mounjaro, and this might need treatment.
Tell your doctor if you have diabetic eye disease or if you experience eye problems during treatment with Mounjaro.
These are not all the side effects. You will find a full list of known side effects in the Patient Information Leaflet. This comes in the medication box.
Like all medications, Mounjaro can cause side effects. But when side effects are listed as common in the Patient Information Leaflet, it doesn’t mean that everyone who takes the medication will get them. Read more about GLP-1 agonist side effects.
The information about side effects is based on the likelihood of people having them. For example, if a side effect is very common, then it can affect more than one in ten people, and if a side effect is very rare, then it affects fewer than one in 10,000 people.
Because medicines can affect people differently, your healthcare team will speak to you about what’s best for you and discuss any side effects.
It’s also important that you take individual advice from your healthcare team before starting treatment and report any side effects to your healthcare professionals if you experience any.
You can also report these side effects to the Yellow Card Scheme, which is the government system used for recording side effects with medicines in the UK.
More information and support with Mounjaro
If you're worried about your medication, struggling with side effects, or want to know if it's right for you, speak with your healthcare team.
Still have more questions? Or is there anything you're not sure about Mounjaro after reading this page? Contact our helpline on 0345 123 2399.
You can visit the NHS website for more information.
