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 2.5mg Cost vs Wegovy — UK Comparison
Mounjaro 2.5mg is the starting dose when you begin tirzepatide treatment for weight management in the UK. If you're comparing costs with Wegovy, it's important to understand that both are prescription-only medications with different pricing structures and availability routes. This guide compares the cost and access routes for both medications, helping you understand what to expect when discussing weight loss options with your GP or a licensed prescriber. Our free GLP-1 weight loss calculator can help you explore projected weight loss at different doses of either medication.
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Calculate Your BMI Instantly
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.
Mounjaro 2.5mg and Wegovy Costs in the UK
Mounjaro 2.5mg starting dose cost: Private prescriptions for Mounjaro typically range from £130–£180 per KwikPen (4-week supply at starting dose) through GPhC-registered pharmacies. The 2.5mg dose is used for weeks 1–4 only, then escalated to 5mg for weeks 5–8, so this is not a long-term cost.
Wegovy starting dose cost: The 0.25mg starting dose of Wegovy typically costs £120–£160 per pen (4-week supply) from private providers. Like Mounjaro, this is escalated weekly over 4 weeks, making it a temporary dose.
Key difference: Mounjaro is a dual GIP and GLP-1 receptor agonist, whilst Wegovy (semaglutide) is a GLP-1 agonist only. Clinical trials showed Mounjaro achieved an average of clinically studied weight loss at the maximum 15mg dose, compared to approximately 14.9% for Wegovy at 2.4mg. However, individual results vary significantly, and suitability depends on your personal health profile and prescriber assessment.
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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.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
Long-Term Costs and NHS Access
The 2.5mg dose itself is temporary — you'll escalate to 5mg, then potentially higher doses based on your response. Total monthly costs depend on your maintenance dose. At maximum dose (15mg Mounjaro or 2.4mg Wegovy), private prescriptions typically cost £200–£320 per month through UK providers.
NHS access: Both Mounjaro and Wegovy may be available through NHS specialist weight management services (tier 3), but availability is limited and varies significantly by region (Integrated Care Board). Waiting lists can be months or longer. Your GP can assess whether you meet eligibility criteria and discuss referral options. Eligibility generally requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions like type 2 diabetes or hypertension.
- 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.
Is Mounjaro 2.5mg a full dose or just a starting dose?
The 2.5mg dose is purely a starting/adjustment dose used for weeks 1–4 only. After 4 weeks, you escalate to 5mg, and increases continue weekly until you reach your optimal maintenance dose (typically 10mg–15mg). You will not remain on 2.5mg long-term.
How does Mounjaro 2.5mg cost compare to other Mounjaro doses?
All doses of Mounjaro in a KwikPen cost roughly the same per pen (approximately £130–£180), regardless of whether it's 2.5mg, 5mg, or 15mg. You pay for the pen, not the dose amount. Each pen lasts 4 weeks.
Can I get Mounjaro on the NHS instead of paying privately?
Mounjaro may be available through NHS specialist tier 3 weight management services, but availability is very limited and varies by region. Your GP can assess your eligibility (BMI 30+, or 27–29.9 with health conditions) and discuss referral options. NHS waiting lists are often lengthy.
What's the difference between Mounjaro and Wegovy in terms of effectiveness?
Clinical trials showed different results: Mounjaro (tirzepatide) achieved an average clinically studied weight loss at maximum dose, whilst Wegovy (semaglutide) showed approximately 14.9%. However, individual results vary widely. Both work alongside diet and exercise. Your prescriber will advise which is suitable for you based on your health profile.
How do I know if I'm eligible for Mounjaro 2.5mg?
Eligibility requires a BMI of 30 kg/m² or above, or 27–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea, etc.). South Asian, Chinese, Black African, and Black Caribbean adults may have lower BMI thresholds. A GP or licensed prescriber will assess your suitability during a clinical consultation. Use our free BMI calculator to check your current BMI.
Ready to take control of your weight loss journey?
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