Mounjaro Weight Loss Injections

Diet UK treatment fees include the medication, all follow-up consultations, medical advice and ongoing support throughout your programme.

First consultation: £50. Adolescent patients: £100.

You may be suitable for Mounjaro if you are an adult with:

• A BMI of 30 or above (clinically classified as obesity), or
• A BMI of 27 or above with at least one weight-related health condition such as high blood pressure, raised cholesterol, type 2 diabetes, prediabetes or obstructive sleep apnoea

Mounjaro is not suitable if you:

• Are pregnant, breastfeeding or planning a pregnancy
• Have a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)
• Have a history of pancreatitis or severe gastrointestinal disease
• Are allergic to tirzepatide or any of the inactive ingredients

Final suitability is confirmed by a qualified Diet UK doctor after your consultation. Mounjaro is also available on the NHS under NICE TA1026, but access is being introduced in phases and is currently limited to higher-risk patients (typically a BMI of 35 or above, lower for some ethnic backgrounds, with weight-related health conditions) via a specialist weight management service or an opted-in GP practice. Waiting lists are often long.

Mounjaro contains tirzepatide, which acts on two natural gut hormone receptors at once: GLP-1 and GIP. This dual action is what sets it apart from single-hormone GLP-1 injections such as Wegovy. Once weekly, Mounjaro:

• Reduces hunger and food cravings
• Helps you feel fuller sooner and stay full for longer
• Slows how quickly your stomach empties
• Improves the way your body responds to insulin and helps regulate blood sugar

Mounjaro works best alongside a reduced-calorie diet and regular physical activity.

Mounjaro is one of the most effective weight loss medications licensed in the UK. In the landmark SURMOUNT-1 trial, published in the New England Journal of Medicine in 2022, adults with obesity or overweight who took tirzepatide alongside lifestyle support achieved the following average weight loss over 72 weeks (measured across all participants, regardless of how closely they stuck to treatment):

• 15.0% average weight loss on the 5 mg weekly dose
• 19.5% average weight loss on the 10 mg weekly dose
• 20.9% average weight loss on the 15 mg weekly dose

A separate head-to-head trial, SURMOUNT-5 (New England Journal of Medicine, 2025), directly compared the two medicines and found tirzepatide produced greater average weight loss than semaglutide over 72 weeks.

Individual results vary based on adherence, lifestyle changes and starting weight. The medical supervision at Diet UK is part of what helps patients achieve outcomes closer to clinical trial averages.

Mounjaro starts low and increases gradually to reduce the chance of gastrointestinal side effects. Dose increases are only made when clinically appropriate:

• Weeks 1 to 4: 2.5 mg weekly (starting dose)
• From week 5: increase to 5 mg weekly
• Further increases of 2.5 mg are possible after a minimum of four weeks at the current dose, if needed and tolerated
• Recommended maintenance doses are 5 mg, 10 mg or 15 mg weekly

Your Diet UK clinician decides the right dose and pace for you. Not everyone needs the highest dose; the goal is the lowest dose that keeps you progressing with manageable side effects.

Mounjaro comes as a pre-filled KwikPen. Inject once a week, on the same day, at any time of day:

• Inject under the skin into your abdomen, thigh or upper arm
• Rotate injection sites each week
• Store unopened pens in the fridge. Once in use, pens can be kept at room temperature in line with the patient leaflet
• If you miss a dose, take it as soon as possible within four days. If more than four days have passed, skip it and take your next dose on the usual day

Your Diet UK clinician will demonstrate pen use at your first consultation.

Most common side effects are gastrointestinal and usually settle as your body adjusts:

• Nausea
• Vomiting
• Diarrhoea
• Constipation
• Abdominal pain
• Reduced appetite

Less common but serious side effects include pancreatitis, gallbladder problems, low blood sugar (mainly if combined with other diabetes medicines) and kidney problems linked to dehydration. Contact your Diet UK doctor promptly if you experience persistent severe abdominal pain, or any unusual symptoms. Regular medical reviews throughout treatment are included in your programme.

Mounjaro and Wegovy are the two main weight loss injections licensed in the UK.

Mounjaro targets two appetite-regulating pathways instead of one, which is why its peak weight loss outcomes in trials are slightly higher. Wegovy has a longer track record and dedicated cardiovascular outcome data. Both are licensed by the MHRA. Your Diet UK doctor will help you choose the option that fits your health and goals.

Mounjaro is a prescription-only medicine, so it cannot be bought without a prescription, and it should never be sourced from an unregulated seller. At Diet UK, Mounjaro is prescribed only after a full medical consultation and assessment by a qualified doctor, with monitoring and support included throughout your treatment.

Diet UK is a medically led weight loss clinic in Preston, Lancashire, serving patients across the UK by online video consultation. Every Mounjaro plan is overseen by a qualified doctor, with ongoing support throughout your programme.

How much does Mounjaro cost in the UK?

At Diet UK, treatment fees start from £190 for your first pen at the 2.5 mg starting dose, rising with the dose. The fee includes medication, follow-up consultations and ongoing support. First consultation is £50. Confirm current prices with the clinic before starting.

How quickly does Mounjaro work?

Most patients notice reduced appetite within the first few weeks. Meaningful weight loss usually becomes visible after eight to twelve weeks, with the full clinical effect building over six to twelve months.

Is Mounjaro available on the NHS?

Yes, but access is restricted and being introduced in phases under NICE TA1026. It is currently prioritised for higher-risk adults, typically with a BMI of 35 or above (lower for some ethnic backgrounds) and weight-related health conditions, via a specialist weight management service or an opted-in GP practice. Waiting lists are often long.

Is Mounjaro the same as Wegovy?

No. Mounjaro contains tirzepatide and works on two hormone receptors (GLP-1 and GIP). Wegovy contains semaglutide and works on one (GLP-1). They are different medicines and are not interchangeable.

How long will I need to take Mounjaro?

Mounjaro is licensed for long-term weight management. Many patients stay on it to maintain results, although the decision is reviewed regularly with your clinician. Stopping treatment often leads to some weight regain.