Taken once a week
Mounjaro is usually taken using a once-weekly injection pen. Follow the instructions and advice given by the prescribing service.
Mounjaro
What Mounjaro is
Mounjaro is the brand name for tirzepatide, a prescription-only injectable medicine licensed in the UK for chronic weight management. It is administered as a once-weekly subcutaneous injection using a pre-filled pen. Tirzepatide is classified as a dual GLP-1 and GIP receptor agonist — a different mechanism from earlier single-receptor GLP-1 medicines such as semaglutide (Wegovy).
The Medicines and Healthcare products Regulatory Agency (MHRA) approved tirzepatide for weight management in the UK in November 2023. It is available via private prescription from licensed providers. NHS access via specialist weight management services was approved by NICE in March 2025 (TA1026), but availability depends on local commissioning decisions and waiting lists exist in most areas.
Mounjaro is available in six doses: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg and 15mg. Treatment typically starts at the lowest dose and titrates upward over several months based on tolerability and clinical response. The 2.5mg dose is a starting dose only and is not a maintenance level.
How Mounjaro works
Tirzepatide acts on two hormone receptors: glucagon-like peptide-1 (GLP-1) receptors and glucose-dependent insulinotropic polypeptide (GIP) receptors. Earlier injectable weight-loss medicines such as semaglutide act on GLP-1 receptors only.
GLP-1 receptor activation slows gastric emptying — the rate at which food leaves the stomach — and signals reduced appetite in the brain. This contributes to reduced food intake and a greater feeling of fullness after smaller meals. GIP receptor activation appears to complement these effects and may improve fat metabolism, though the precise interaction between the two pathways continues to be studied.
The combined dual-receptor effect is associated with greater average weight loss in clinical trials than single-receptor GLP-1 medicines at equivalent timepoints. Individual responses vary considerably — starting weight, diet, activity level and metabolic health all influence how much weight a person loses.
Tirzepatide also affects blood glucose regulation. It is separately licensed under the same Mounjaro brand name for type 2 diabetes management in the UK, typically at lower doses.
Who Mounjaro may suit
The licensed criteria for Mounjaro for weight management in the UK are based on BMI and the presence of weight-related health conditions. The general criteria used in private prescribing are:
- Adults with a BMI of 30 kg/m² or above (classified as obese)
- Adults with a BMI of 27 kg/m² or above with at least one weight-related health condition, such as type 2 diabetes, high blood pressure, raised cholesterol, or obstructive sleep apnoea
- People who have made sustained efforts at lifestyle change without achieving sufficient weight loss
- Those who can commit to the follow-up checks and monitoring that responsible prescribers require
Eligibility is always confirmed through a clinical assessment, not by BMI alone. Prescribers review medical history, current medicines, contraindications and individual circumstances before prescribing. This list describes the general licensed population — it is not a guarantee of eligibility for any individual.
Who Mounjaro may not suit
Mounjaro is not appropriate for everyone. Prescribers will typically assess for the following contraindications and cautions:
- Personal or family history of medullary thyroid carcinoma (MTC)
- Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)
- Known hypersensitivity to tirzepatide or any component of the formulation
- Pregnancy, breastfeeding, or planning to become pregnant during the treatment period
- Type 1 diabetes (Mounjaro is not licensed for type 1 diabetes management)
- Severe gastrointestinal disease, including gastroparesis
- Severe renal impairment (prescribing decisions vary; individual clinical review required)
- People using certain other medicines, including some insulins, where interaction review is required
This is not an exhaustive list. A prescribing clinician reviews individual circumstances and may identify additional reasons that Mounjaro is not suitable for a specific person. The patient information leaflet and a qualified healthcare professional are the appropriate sources of complete contraindication information.
Benefits reported in clinical studies
The primary evidence for Mounjaro’s effectiveness in weight management comes from the SURMOUNT clinical trial programme. The figures below are from the published peer-reviewed literature.
22.5%
Mean weight loss at 15mg
SURMOUNT-1, 72 weeks, adults without diabetes. Placebo: 2.4%.
89%
Achieved ≥5% weight loss
SURMOUNT-1, 15mg arm. Placebo: 29%.
57%
Achieved ≥20% weight loss
SURMOUNT-1, 15mg arm. Placebo: 3%.
SURMOUNT-1 (Jastreboff et al., NEJM, 2022) enrolled adults with obesity or overweight with weight-related health conditions, without type 2 diabetes. At the 15mg dose, mean body weight reduction was 22.5% at 72 weeks. All participants followed a reduced-calorie diet and increased physical activity programme alongside medication.
SURMOUNT-2 (Garvey et al., Lancet, 2023) enrolled adults with type 2 diabetes. Mean weight loss was 15.7% at 15mg and 14.7% at 10mg at 72 weeks, with additional improvements in HbA1c, blood pressure, waist circumference and lipid profiles across trial arms.
SURMOUNT-5 (2025) was a direct head-to-head comparison of tirzepatide against semaglutide 2.4mg (Wegovy) in adults without type 2 diabetes. At 72 weeks, tirzepatide produced 20.2% mean weight loss versus 13.7% for semaglutide. This is the only published randomised trial directly comparing the two medicines.
Clinical trial participants receive structured monitoring by specialist teams and follow controlled dietary and activity programmes. Outcomes in real-world private prescribing settings may differ materially. No trial result should be read as a guaranteed individual outcome.
Sources: Jastreboff AM et al. NEJM 2022; Garvey WT et al. Lancet 2023; Aronne LJ et al. NEJM Evidence 2025 (SURMOUNT-5). Full trial data available through the SURMOUNT programme publications.
Potential limitations
- Weight regain after stopping. Most evidence shows that significant weight is regained when Mounjaro is discontinued. SURMOUNT-4 withdrawal data found people who stopped after 36 weeks of active treatment regained a mean of 14.8 percentage points of their weight loss over the following year. The implications of long-term or indefinite treatment should be discussed with a prescriber before starting.
- Cost over time. Starting doses are available from around £110 per month via private providers. Later doses at 10mg to 15mg typically cost £229 to £375 per month. The sustained financial commitment is significant and worth planning for before beginning treatment.
- Variable prescribing quality. Online private prescribing quality varies considerably across providers. Clinical assessment depth, follow-up practices, dosing guidance and side-effect support differ. Price alone is not a reliable indicator of clinical quality.
- Gastrointestinal side effects. Most people experience some gastrointestinal symptoms, particularly in early treatment stages and after dose increases. These are generally dose-dependent and often improve over time, but they affect adherence for a portion of users.
- Supply availability. UK supply of Mounjaro injection pens has been subject to intermittent constraints. Availability can vary by dose and provider. Confirming current stock with a provider before committing is worth doing.
- NHS access remains limited. NICE approval (TA1026, March 2025) covers specialist weight management services only. Referral eligibility, waiting lists and local commissioning decisions mean NHS access is not available to most people in the near term.
Side effects overview
The following summarises side effects reported in clinical trials and post-marketing experience. It is not a complete list. The patient information leaflet provided with Mounjaro contains the full prescribing information and should be read before starting treatment.
Common — affects more than 1 in 10
- Nausea — most frequent in early weeks and after dose increases; usually improves over time
- Diarrhoea
- Vomiting
- Constipation
- Decreased appetite
- Injection site reactions (redness, swelling or bruising at the injection site)
Less common — affects between 1 in 10 and 1 in 100
- Fatigue
- Dyspepsia (indigestion and reflux)
- Abdominal discomfort or pain
- Dizziness
- Hair thinning (telogen effluvium) — usually temporary and related to rapid weight loss rather than the medicine directly
- Increased heart rate
Rare — seek urgent medical attention
- Pancreatitis — seek urgent medical attention if you experience severe, persistent abdominal pain, particularly if it radiates to the back
- Gallbladder problems, including gallstones (cholelithiasis)
- Serious allergic reactions (anaphylaxis) — seek emergency help immediately if symptoms of a severe allergic reaction occur
- Diabetic retinopathy complications (in people with type 2 diabetes)
Any side effects should be discussed promptly with the prescribing provider. Before starting treatment, confirm that the provider has a clear and accessible clinical support process for reporting and managing side effects during treatment.
What people often ask before starting
Does Mounjaro work without changing diet and exercise?
The SURMOUNT trials combined tirzepatide with a structured reduced-calorie diet and increased physical activity. Mounjaro is licensed as an adjunct to lifestyle changes, not as a standalone treatment. In practice, the appetite-suppression effect tends to support dietary changes, but the medicine is intended to be used within a structured programme rather than in place of one.
How long does treatment last?
Mounjaro is not approved as a short-course treatment. The published trial evidence covers 72 weeks and beyond, with weight regain observed after stopping. For most people who respond well, current clinical guidance treats this as an ongoing intervention rather than a time-limited course. The long-term plan — including how any eventual discontinuation would be managed — should be discussed with a prescriber before starting.
Can I get Mounjaro on the NHS?
NICE approved Mounjaro for use in specialist NHS weight management services in March 2025 (TA1026). Access depends on local commissioning decisions, referral eligibility and waiting lists. Most people currently access Mounjaro via private providers. NHS routes and timelines vary considerably by area; your GP can advise on local availability.
What happens if I stop treatment?
Weight regain is common after stopping. The SURMOUNT-4 withdrawal study (2023) found that people who stopped tirzepatide after 36 weeks of active treatment regained a mean of 14.8 percentage points of their weight loss over the following 52 weeks, compared to continued modest weight reduction in those who remained on treatment. Weight regain is a well-documented characteristic of this drug class and should be understood before starting.
How does Mounjaro compare to Wegovy?
Both are once-weekly injections for weight management. Wegovy (semaglutide) acts on GLP-1 receptors only; Mounjaro (tirzepatide) acts on both GLP-1 and GIP receptors. The SURMOUNT-5 trial (2025) directly compared the two: tirzepatide produced 20.2% mean weight loss versus 13.7% for semaglutide at 72 weeks in adults without type 2 diabetes. Individual response varies, and tolerability, cost and availability also affect the decision. A full comparison is available on this site.
What matters before you judge the price
Later doses can cost differently
Provider tables often show several strengths. The lowest starter price may not reflect the cost of later doses.
Assessment comes first
Suitability depends on a clinical assessment, medical history, current medicines and the provider’s prescribing process.
Support matters after the first order
Follow-up, side-effect guidance, delivery handling and restart rules can become more important once treatment is underway.
How to read the provider table
Dose shown
Compare the same dose first. A 2.5mg starter price should not be treated as the same thing as a later higher-dose price.
Price and delivery
Check whether delivery is included, whether a discount affects the price, and whether checkout fees could change the total.
Checks and support
Look beyond the price row: online assessment, pharmacy review, repeat-order rules and restart guidance can all affect the decision.
Why later doses change the total
Mounjaro provider pages usually show multiple strengths. The starting dose is not a permanent price promise, and later dose stages can change both the monthly cost and the amount of support someone wants. Look beyond the first visible number and check the full dose range shown.
Starter stage
Check first-month cost, assessment clarity and how the provider explains getting started.
Dose changes
Check whether the provider explains dose reviews, side-effect support and how questions are handled.
Longer-term use
Check support, maintenance details, repeat checks and what happens if treatment pauses.
NHS and private routes are different
NHS access, private prescribing and online provider comparison are related, but they are not the same question. NHS access is usually about eligibility and local pathway. Private provider comparison is more about assessment quality, price visibility, delivery, support and whether the service explains its limits clearly.
NHS access
Check eligibility, local pathway and whether specialist weight-management support is involved.
Private providers
Check clinical assessment, price transparency, provider registration, delivery handling and support.
More detail
Use WLC for the broad overview and Jaro Compare when you want deeper Mounjaro provider detail.
What to check before you choose a provider
| Area | Why it matters | What to look for |
|---|---|---|
| Suitability | Mounjaro is not suitable for everyone. | Health questions, current medicines, BMI information and clinical review before treatment is considered. |
| Side effects | People often need practical guidance once treatment starts. | Plain-English information on common side effects, warning signs and how to contact the provider. |
| Delivery | Injection pens need appropriate handling. | Clear delivery timing, packaging information and what to do if a parcel is delayed, damaged or warm. |
| Continuation | The first order is only one part of treatment. | Repeat checks, dose-review details, support access and what happens after a pause or provider switch. |
For deeper Mounjaro provider detail
WeightLossComparison keeps this page focused on the main treatment and provider questions. For deeper Mounjaro-specific pricing, maintenance, restart, support and delivery detail, use the specialist Jaro Compare pages.
Jaro provider table
Compare Mounjaro providers with specialist filters and more detailed provider pages.
Delivery checklist
Review clinical review time, dispatch, courier and temperature-handling questions.
Provider types
Understand price-first, support-focused, maintenance and restart-style services.
Maintenance shortlist
Look at ongoing-care information once treatment is established.
Related guides
Wegovy guide
Compare another weekly injection before focusing too quickly on provider pages.
Mounjaro vs Wegovy
Use a side-by-side comparison if you are weighing up the two weekly injections.
NHS vs private
Compare access options if your real question is where care should begin.
Provider checks
Use a practical checklist before relying on any online treatment service.
Confirm current details with the provider
Prices, dose availability, delivery terms, eligibility details and support policies can change. Check the current information directly with the provider or a qualified healthcare professional before you decide.
Treatment next step
Move from treatment research into the provider shortlist
Treatment pages attract strong intent, but the useful next step is usually the clinic comparison, provider evidence and a broader look at how treatments differ in practice.
Related comparison guides
Related comparison guides
Use these links when you want a nearby treatment, provider or safety question explained in more detail.Wegovy provider contextDeeper Wegovy provider and dose-price context.Wego CompareMounjaro provider contextDeeper Mounjaro provider and dose-price context.Jaro CompareTablet and capsule contextOral treatment route, pack, price and provider-check context.Tablet route
These links are optional comparison guides, not treatment recommendations. Suitability and provider details should be checked directly with the relevant provider.
Provider pricing by dose
| Dose | Lowest price found | Highest price found | Providers |
|---|---|---|---|
| 2.5mg | £109.95 | £229.00 | 68 |
| 5mg | £139.95 | £259.00 | 68 |
| 7.5mg | £199.95 | £299.50 | 68 |
| 10mg | £229.00 | £339.50 | 68 |
| 12.5mg | £246.00 | £349.50 | 68 |
| 15mg | £265.96 | £374.50 | 68 |
Common questions
Can this site tell me which treatment is suitable?
No. The site can help you compare routes and questions to ask, but suitability depends on clinical assessment by a regulated provider.
Why does the parent site link to Wego and Jaro?
The parent site covers broad route decisions. Wego and Jaro remain the specialist sites for deeper Wegovy and Mounjaro provider detail.
Are prices fixed?
No. Prices, delivery costs, offer terms, eligibility and availability can change. Always confirm current information directly with the provider.
Does the site sell medicines?
No. It is informational and comparison-led. It does not sell, prescribe or supply prescription-only medicines.