Mounjaro Frequently Asked Questions

What is Mounjaro?

Mounjaro is a prescription medicine containing tirzepatide. [1,2,4]
It is licensed for weight loss and weight maintenance in eligible adults.
It is also used to treat type 2 diabetes. [1,2]

How does Mounjaro work for weight loss?

Mounjaro acts on two natural hormone systems called GIP and GLP-1. [1]
It helps you feel fuller.
It reduces hunger and food cravings.
This can help you eat less and lose weight. [1,2]

Does Mounjaro burn fat or increase metabolism?

It is not simply a “fat-burning” medicine.
It mainly helps by reducing appetite and food intake.
It also affects how the body uses fat.
Studies found that most of the weight lost was body fat, including fat around the internal organs. [1]

Does Mounjaro suppress appetite and reduce food cravings?

Yes.

It can make you feel fuller.
It can reduce hunger.
It can reduce food cravings.
These effects can help reduce how much you eat. [1,2]

Does Mounjaro shrink your stomach?

No.

Mounjaro does not physically make your stomach smaller.
It slows how quickly food leaves your stomach and helps you feel fuller for longer. [1]

What BMI do I need for Mounjaro for weight loss?

For the licensed use in adults:

BMI 30 kg/m² or above, or
BMI 27 to below 30 kg/m² with at least one weight-related health problem. [1,2]
Suitability still requires an individual clinical assessment.

These are the medicine's licensed criteria and are different from NHS funding/access criteria

What is the age limit for Mounjaro for weight loss?

Mounjaro is licensed for weight management in adults aged 18 years and over. [1,2]
Its safety and effectiveness for weight management have not been established in people under 18. [1]
There is no specific upper age limit in the licence, although information in people aged 85 and over is very limited. [1]

What doses of Mounjaro are available?

Mounjaro KwikPens are available as:

2.5 mg
5 mg
7.5 mg
10 mg
12.5 mg
15 mg [1,2]

What is the starting dose of Mounjaro?

The usual adult schedule starts:

2.5 mg once weekly for 4 weeks
Then 5 mg once weekly
If needed, the dose can then be increased by 2.5 mg at a time.
You should normally stay on each dose for at least 4 weeks before increasing. [1,2]

Do not change your dose unless your prescriber tells you to. [2]

What is the maintenance dose and maximum dose of Mounjaro?

Recommended maintenance doses are 5 mg, 10 mg or 15 mg once weekly.
The maximum adult dose is 15 mg once weekly. [1]
7.5 mg and 12.5 mg are normally steps used when increasing the dose. [1,2]

Do I have to increase my Mounjaro dose every 4 weeks?

No.

After the initial increase from 2.5 mg to 5 mg, further increases are made only if needed. [1,2]
Each dose should normally be used for at least 4 weeks before considering an increase.
Do not increase the dose yourself. [1,2]

Do you lose more weight on a higher dose of Mounjaro?

On average, higher doses produced greater weight loss in a major study. [1]

However:

A higher dose does not guarantee more weight loss for an individual.
Higher doses may also cause more side effects.
Your dose should be based on your response and how well you tolerate the medicine. [1]

Why am I not losing weight on Mounjaro?

People respond differently to Mounjaro.
Weight loss may vary between doses and between individuals.
Treatment should be used alongside a reduced-calorie diet and increased physical activity. [1,2]
If you have not lost at least 5% of your starting weight 6 months after reaching your highest tolerated dose, your prescriber should review whether treatment should continue. [1]

How much weight can I lose with Mounjaro?

Results vary considerably.

In a 72-week study, average weight loss was approximately:

16.0% with 5 mg
21.4% with 10 mg
22.5% with 15 mg
2.4% with inactive treatment. [1]
These are study averages, not a prediction of how much an individual will lose.

How long can you stay on Mounjaro?

Mounjaro is licensed for both weight loss and weight maintenance. [1]
The product information does not set a fixed maximum treatment duration.
Whether treatment continues should depend on your individual benefits, risks and response. [1]

What happens when you stop Mounjaro?

Do not stop Mounjaro without discussing it with your prescriber. [2]
Weight regain can occur after treatment is stopped.
In a study, people who continued Mounjaro maintained their weight loss better than people who stopped treatment. [1]
If you have type 2 diabetes, stopping Mounjaro may also cause your blood sugar to rise. [2]

What is the best time to take Mounjaro?

Mounjaro can be injected at any time of day.
It can be taken with or without food.
Try to use it on the same day each week. [1,2]

Where do I inject Mounjaro?

Mounjaro is injected under the skin of the:

Stomach
Upper leg
Back of the upper arm [1,2]
Use a different injection spot each time. [1,2]

How many doses are in a Mounjaro KwikPen?

Each Mounjaro KwikPen contains 4 full doses. [1,2]
Needles are not included with the pen. [1]
A new needle should be used according to the official pen instructions

Is there a fifth dose in a Mounjaro pen?

No official fifth dose is provided.
Each KwikPen is designed to provide 4 doses.
A small amount of medicine may remain after the fourth dose.
The official instructions specifically say not to use the remaining medicine.
The pen should then be discarded. [1,2]

Can I use a Mounjaro click chart to take a different dose?

Do not use unofficial click charts to alter your prescribed dose.
Mounjaro KwikPens are supplied in specific strengths.
The official instructions say not to change your dose unless your doctor has told you to. [2]
Dose changes should be agreed with your prescriber.

How should Mounjaro be stored?

Before use:

Store it in a refrigerator at 2°C to 8°C.
Do not freeze it. [1,2]

After first use:

It can be kept outside the refrigerator for up to 30 days, provided the temperature stays at or below 30°C.
It must then be discarded. [1,2]
If the pen has frozen, do not use it. [1,2]

What are the most common side effects of Mounjaro?

Common side effects include:

Feeling sick
Diarrhoea
Being sick
Constipation
Stomach pain
Indigestion
Bloating
Heartburn
Feeling tired [1,2]

Stomach-related side effects are often worse when starting or increasing the dose and commonly improve with time. [1,2]

Which Mounjaro side effects need urgent medical attention?

Seek urgent medical help if you develop:

Severe and persistent stomach pain, especially if it spreads to your back.
Difficulty breathing.
Rapid swelling of your lips, tongue or throat. [1,2]

These may indicate a serious problem such as inflammation of the pancreas or a severe allergic reaction. [1,2]

Can Mounjaro affect the kidneys or liver?

Most people with kidney or liver problems do not automatically need a different dose. [1]
Extra caution is needed in severe kidney or liver problems because experience is limited.
Vomiting or diarrhoea can cause dehydration, which may worsen kidney function. [1,2]
Suitability should therefore be assessed individually.

Does Mounjaro lower blood sugar and treat diabetes?

Yes.

Mounjaro is licensed to treat type 2 diabetes. [1,2]
It can reduce high blood sugar levels.
It can be used alone in some people or alongside other diabetes medicines. [1,2]

Mounjaro is not licensed as a treatment for type 1 diabetes. [1]

Can Mounjaro be taken with other medicines?

Often yes, but your prescriber needs to know what medicines you take.

Mounjaro slows how quickly the stomach empties and can affect how quickly some tablets are absorbed. [1]
Extra monitoring may be needed with medicines such as warfarin or digoxin.
If used with insulin or certain diabetes tablets, the risk of low blood sugar can increase and their doses may need adjusting. [1,2]

Is Mounjaro available as tablets, pills or patches in the UK?

Currently, the UK eMC lists Mounjaro as KwikPen injections in six strengths. [1,3]

No Mounjaro tablet is currently listed.
No Mounjaro pill is currently listed.
No Mounjaro patch is currently listed. [3]

What should I eat while taking Mounjaro?

Mounjaro should be used alongside a reduced-calorie diet. [1,2]
There is no single Mounjaro diet that everyone must follow.
Your eating plan should be appropriate for your individual nutritional and weight-management needs.

How many calories should I eat while taking Mounjaro?

The official Mounjaro information does not give one calorie target for everyone.
It states that treatment should be combined with a reduced-calorie diet and increased physical activity. [1,2]
Your calorie requirements depend on factors such as your body size, age and activity level.

How much water should I drink while taking Mounjaro?

The Mounjaro product information does not give one fixed daily amount of water for everyone.
It is important to avoid dehydration.
Drink plenty of fluids if you develop sickness or diarrhoea. [1,2]

Do I need vitamins or supplements while taking Mounjaro?

The official Mounjaro product information does not recommend a specific vitamin supplement for everyone. [1,2]
Your nutritional requirements should be assessed individually, particularly if you are eating substantially less food.

Do I need to exercise while taking Mounjaro?

Mounjaro is intended to be used alongside increased physical activity. [1,2]
Physical activity remains part of weight management while using Mounjaro.
The product information does not specify one exercise programme that everyone must follow.

Do I need to follow keto or intermittent fasting while taking Mounjaro?

No specific keto or fasting diet is required.

The official Mounjaro information recommends a reduced-calorie diet and increased physical activity. [1,2]
It does not require a ketogenic diet.
It does not require intermittent fasting

Does Mounjaro reduce belly fat and visceral fat?

Studies show that Mounjaro can reduce body fat.

Most of the weight lost in one body-composition study came from fat tissue.
Fat around the internal organs, known as visceral fat, was also reduced. [1]
Mounjaro does not specifically target only belly fat.

Can Mounjaro lower blood pressure and cholesterol?

Studies found improvements in:

Blood pressure
Total cholesterol
LDL cholesterol
Triglycerides [1]

However, Mounjaro should not be considered a replacement for medicines prescribed specifically to treat high blood pressure or cholesterol.

Does Mounjaro cause cancer?

Mounjaro has not been shown to cause cancer in humans in the product information. [1]
Thyroid tumours occurred in studies involving rats.
The product information states that the relevance of this finding to humans is unknown. [1]

Is Mounjaro better than Wegovy for weight loss?

A direct 72-week study compared tirzepatide with semaglutide.

Average weight loss was 21.6% with tirzepatide.
Average weight loss was 15.4% with semaglutide. [1]
This does not mean Mounjaro is automatically the best treatment for every person.
The choice should be based on individual suitability, safety, response and preference.

Can Mounjaro help with sleep apnoea?

Sleep apnoea is listed as one of the weight-related conditions relevant to Mounjaro's weight-management criteria. [1,2]
Studies reported improvements in sleep apnoea in adults with obesity who received tirzepatide. [1]
Mounjaro's UK SmPC does not list sleep apnoea as a separate standalone licensed indication. [1]

Can Mounjaro be used specifically for PCOS or binge eating?

Mounjaro is not specifically licensed to treat PCOS or binge-eating disorder. [1]
Its licensed uses are type 2 diabetes and weight management in people who meet the relevant criteria. [1]
Someone with another condition may still potentially meet the weight-management criteria, but this requires an individual clinical assessment.

Who makes Mounjaro and what is the active ingredient?

The active ingredient is tirzepatide. [1,2]
Mounjaro is an Eli Lilly medicine.
Eli Lilly and Company Limited is the UK company listed on eMC. [1,2]

How long has Mounjaro been available in the UK?

The current UK Mounjaro SmPC records its first UK authorisation as 25 January 2024. [1]
The medicine and its approved information have continued to be updated since then

Can I get Mounjaro on the NHS for weight loss?

Yes, but NHS access is currently restricted and being introduced gradually.
NICE recommends Mounjaro for certain adults with obesity and weight-related health problems. [5]
NHS England is introducing access in stages, starting with people with the greatest clinical need. [6]
NHS eligibility is therefore more restrictive than the general licence for Mounjaro. [5,6]
Local NHS pathways can also affect how treatment is accessed. [6]

Can my GP prescribe Mounjaro for weight loss?

Yes, but not everyone who meets the medicine's licence will qualify for NHS treatment.
Mounjaro can be prescribed through NHS primary care where the appropriate local pathway is available. [6]
NHS England is currently using phased eligibility criteria.
Your GP or local weight-management service can advise whether you meet the current NHS criteria. [6]

References

[1] Eli Lilly and Company Limited. Mounjaro KwikPen 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg and 15 mg solution for injection in pre-filled pen – Summary of Product Characteristics (SmPC). electronic Medicines Compendium (eMC). Last updated 16 April 2026; text revised 9 April 2026.
[2] Eli Lilly and Company Limited. Mounjaro KwikPen 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg and 15 mg solution for injection in pre-filled pen – Patient Information Leaflet (PIL). electronic Medicines Compendium (eMC). Last updated 15 April 2026; leaflet revised April 2026.
[3] electronic Medicines Compendium (eMC). Medicines containing the active ingredient tirzepatide. Current UK product listing. Accessed 26 August 2026.
[4] NICE. British National Formulary (BNF): Tirzepatide. British National Formulary. Accessed 26 August 2026.
[5] National Institute for Health and Care Excellence (NICE). TA1026: Tirzepatide for managing overweight and obesity. Published December 2024.
[6] NHS England. Interim commissioning guidance: implementation of NICE TA1026 and the funding variation for tirzepatide (Mounjaro) for obesity. Updated April 2026.

Disclaimer:

This content was prepared with the assistance of AI and has been reviewed, edited and approved by Hassan Bhatti (Pharmacist Independent Prescriber), before publication. It is intended for general information only and does not replace individual medical advice

Reviewed: 01-Sep-2026