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
Free tracker included with every download this week
How Much Will Mounjaro and Wegovy Cost in September?
Mounjaro and Wegovy costs in the UK vary depending on your dose, where you access treatment, and whether you're using NHS or private services. As of September, private prescription prices typically range from £129 to £320 per month across UK online pharmacies, though exact costs depend on your starting dose and how quickly you escalate. NHS access remains limited to specialist weight management services in most regions, with significant waiting lists. Understanding the cost difference between these two GLP-1 medications — and how pricing aligns with your clinical needs — helps you make an informed decision with your prescriber.
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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 KwikPen Costs vs Wegovy Pricing in September
Mounjaro (tirzepatide) through private online prescribing typically costs £129–£320 per month depending on your dose. You start on a 2.5 mg Mounjaro KwikPen and escalate weekly — so your early costs may be lower than the maximum dose price. Each KwikPen contains 4 weeks of injections.
Wegovy (semaglutide) pricing generally ranges from £130–£290 per month through private UK prescribing. Like Mounjaro, Wegovy escalates over weeks (starting at 0.25 mg), so initial doses cost less than the 2.4 mg maintenance price.
- Both require a GPhC-registered UK pharmacy and a UK-licensed prescriber assessment
- Neither is typically available on NHS prescription outside specialist tier 3 weight management services
- Monthly costs assume you continue at each dose for 4 weeks before escalating
- Prices fluctuate and vary between providers — always confirm current costs with your chosen pharmacy
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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.
Clinical Effectiveness: SURMOUNT vs STEP Trial Data
Mounjaro (dual GIP+GLP-1 agonist) showed average weight loss of 15–21% of body weight across the SURMOUNT trial at various doses. The 15 mg dose demonstrated approximately clinically studied weight loss at 72 weeks when combined with diet and activity changes.
Wegovy (GLP-1 only) demonstrated average weight loss of approximately 14.9% of body weight in the STEP-1 trial at the maximum 2.4 mg dose over 68 weeks, also alongside lifestyle modifications.
Individual results vary significantly. Your GP or prescriber will assess which mechanism suits your health profile best. Cost alone should not guide the decision — clinical suitability, side effect tolerance, and your personal health context matter more. Use our GLP-1 weight loss calculator to explore potential outcomes at different doses.
- 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.
Will Mounjaro cost less than Wegovy in September?
Not necessarily. Both medications typically cost £129–£320 per month privately in the UK, depending on dose. Mounjaro may cost slightly more at higher doses (up to 15 mg) because you're paying for more active drug. Early doses of either medication cost less. Exact September pricing varies by pharmacy — contact your provider for current quotes.
Can I get Mounjaro on the NHS in September?
NHS access to Mounjaro remains limited to specialist tier 3 weight management services in most regions. Eligibility and availability vary significantly by local ICB (Integrated Care Board). Waiting lists are often months to years long. Your GP can refer you, but private prescription may be quicker if you meet clinical eligibility criteria.
What's the difference between Mounjaro dose titration and Wegovy escalation?
Both medications start at a low dose and increase weekly. Mounjaro starts at 2.5 mg and increases to a maximum of 15 mg. Wegovy starts at 0.25 mg, reaching a maximum of 2.4 mg. Mounjaro's higher maximum dose reflects its dual mechanism (GIP+GLP-1). Each step-up usually requires 4 weeks at the current dose before moving higher.
Why might Mounjaro cost more than Wegovy at September checkout?
Mounjaro's maximum dose (15 mg) is significantly higher than Wegovy (2.4 mg). If you're escalating to a high Mounjaro dose, you're receiving more active medication per injection. Additionally, Mounjaro's dual GIP+GLP-1 mechanism may command a slightly higher price. However, both medications vary in cost depending on your specific dose and provider.
Should I choose Mounjaro or Wegovy based purely on September cost?
No. A prescriber will assess your medical history, weight-related health conditions, and personal tolerance to recommend the most suitable option. Clinical effectiveness and side effects matter more than a £20–30 monthly difference. Use our BMI calculator to check your eligibility, then discuss both options with your healthcare provider based on clinical fit, not cost alone.
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.