The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
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Mounjaro 15mg in the UK — Cost, Access & Eligibility
Mounjaro (tirzepatide) 15mg is the maximum prescribed dose for weight management in the UK, though most people reach it gradually through dose titration rather than starting at this level. Understanding how to access it, what it costs, and the different routes available—NHS or private—is essential if you're considering this prescription medication. This guide covers UK-specific access routes, pricing context, and what to expect from the consultation process.
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Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
Private Prescription Costs for Mounjaro 15mg in the UK
The cost of Mounjaro 15mg through private online prescription services in the UK typically ranges from £180 to £320 per month, depending on the provider and service model. Each KwikPen contains four weeks of injections, making this a monthly supply. Private costs may also include the consultation fee (usually £20–£50) and delivery charges. Unlike Ozempic (which uses the same active ingredient semaglutide but at lower doses), Mounjaro works via a dual GIP and GLP-1 mechanism, which can affect both pricing and clinical outcomes. It's important to note that private prescribing requires a clinical assessment from a UK-licensed prescriber—it's not available without professional evaluation, regardless of cost. Many private services offer repeat prescription arrangements once you've been assessed, allowing you to reorder at subsequent doses as your treatment progresses through the titration schedule.
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How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
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NHS vs Private Routes — What's Different
NHS access: Available through tier 3 specialist weight management services following GP referral. NICE has approved tirzepatide (Mounjaro) for NHS use, but availability varies significantly by region and waiting times can be lengthy—sometimes 6 months to over a year in some ICBs. NHS prescribing is free once approved.
Private access: Available immediately following an online clinical assessment with a UK-licensed prescriber. No GP referral needed. You pay per dose but can start within days. Both routes require eligibility assessment (BMI ≥30, or BMI ≥27 with weight-related health conditions). Use our GLP-1 weight loss calculator to explore projected outcomes at the 15mg dose.
- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
How much does Mounjaro 15mg cost privately in the UK?
Private Mounjaro 15mg costs typically range from £180–£320 per month through UK online pharmacies. This covers a four-week supply (one KwikPen with four weekly injections). Consultation fees (£20–£50) and delivery charges may apply separately. Prices vary by provider and whether you're on a subscription or pay-as-you-go service.
Can I get Mounjaro on the NHS in the UK?
Yes, NICE has approved tirzepatide for NHS specialist weight management services. Access is through tier 3 services following a GP referral. Availability and waiting times vary significantly by region (ICB). Once approved, it's free on the NHS, but the referral and assessment process can take many months.
What's the difference between Mounjaro and Wegovy in terms of access?
Both are prescription-only and require clinical assessment. Mounjaro is a dual GIP/GLP-1 agonist; Wegovy is GLP-1-only. Both are available privately through online consultations. NHS access for both depends on regional specialist services. Mounjaro dose titration and Wegovy dose titration follow different schedules, so costs may differ over time.
Do I need a GP referral to get Mounjaro privately?
No, private online prescribing doesn't require a GP referral. You'll complete an online clinical assessment with a UK-licensed prescriber, who decides if Mounjaro is suitable based on your BMI, health conditions, and medications. Your GP doesn't need to be involved, though it's recommended to inform them of any prescription medication you start.
What happens after my initial Mounjaro 15mg prescription—do I need reassessment?
After your initial prescription, most private providers offer repeat prescriptions at your current dose without needing a full reassessment each time. However, if you have new symptoms, side effects, or changes in health, your prescriber may recommend a review. You'll also need a new assessment if switching between providers or changing dose significantly.
Ready to take control of your weight loss journey?
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