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 Price List and Cost Comparison vs Wegovy
Understanding the cost of weight loss injections in the UK is important when considering treatment options. Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription-only medications available through NHS specialist services or private prescribing, but their pricing differs significantly. This guide breaks down actual UK prices, dose costs, and how the two medications compare in terms of cost, mechanism, and clinical outcomes so you can make an informed decision with your GP or prescriber.
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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.
Mounjaro vs Wegovy: UK Pricing and Dose Comparison
Mounjaro (tirzepatide) pricing in the UK typically ranges from £149–£299 per month depending on dose and provider. A single KwikPen contains four weekly doses (one month supply). Each dose level—from 2.5 mg to 15 mg—increases in price as you progress through the escalation schedule.
Wegovy (semaglutide) costs between £129–£275 per month on the private market, also depending on dose. Wegovy pens contain four weekly doses.
- Starting doses: Mounjaro begins at 2.5 mg; Wegovy at 0.25 mg (lower starting dose)
- Maximum doses: Mounjaro reaches 15 mg; Wegovy reaches 2.4 mg
- Escalation: Mounjaro escalates every 4 weeks; Wegovy escalates every 4 weeks
- Treatment duration: Both are typically long-term medications—ongoing costs apply
Prices vary by online pharmacy and prescriber. NHS access eliminates private costs but involves referral to specialist tier 3 weight management services, which may have waiting lists of several months to over a year depending on your region.
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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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Clinical Effectiveness and Individual Suitability
The two medications work differently. Mounjaro is a dual GIP and GLP-1 receptor agonist, whilst Wegovy activates GLP-1 only. SURMOUNT clinical trials showed Mounjaro achieved average weight loss of 15–21% of body weight, whilst STEP trials showed Wegovy achieved approximately 14.9% average loss. However, individual results vary significantly—some people respond better to one medication than the other.
Your prescriber will assess which medication suits your health profile based on your medical history, any weight-related conditions, and how your body may respond. Both require ongoing clinical assessment and are used alongside a reduced-calorie diet and increased physical activity. Prices and availability should not be the only factor—clinical suitability, side effect tolerance, and your personal health context matter more.
- 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 cost per month in the UK?
Private Mounjaro costs typically range from £149–£299 per month depending on your dose level and the online pharmacy. Each KwikPen contains four weekly doses (one month supply). Starting doses (2.5 mg) are cheaper than maximum doses (15 mg). NHS access is free but requires a GP referral to specialist weight management services.
Is Wegovy cheaper than Mounjaro in the UK?
Wegovy is often slightly cheaper, ranging from £129–£275 monthly. However, pricing varies by provider and dose. Both medications cost roughly the same over time. The choice should not be based on cost alone—your GP or prescriber will assess which medication is clinically appropriate for you.
What's included in the monthly Mounjaro or Wegovy cost?
The price covers one KwikPen device, which contains four weekly injections (one month's supply). You pay for the medication only—not GP consultations, follow-up appointments, or injections themselves if self-administering. Online prescribers typically charge separately for the clinical assessment.
Are Mounjaro and Wegovy free on the NHS?
Yes, if prescribed through NHS specialist weight management services (tier 3). However, NHS access requires a referral from your GP and assessment by a multidisciplinary team. Availability and waiting times vary significantly by region—some areas have waiting lists exceeding one year. Private prescribing is faster but involves out-of-pocket costs.
Which is more effective—Mounjaro or Wegovy?
Clinical trials show similar overall weight loss (15–21% for Mounjaro, approximately 15% for Wegovy). Individual responses vary—some people respond better to tirzepatide's dual mechanism, others to semaglutide's GLP-1-only approach. Your prescriber will assess your medical history to recommend the most suitable option. Use our free GLP-1 weight loss calculator to estimate potential outcomes at different doses.
Ready to take control of your weight loss journey?
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