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
Why Is Mounjaro Price Going Up in the UK?
Mounjaro prices have increased significantly in the UK private market over recent months. This is driven by several factors including supply constraints, increased demand, and manufacturing costs. Understanding why Mounjaro KwikPen prices are rising—and how this compares to Wegovy—can help you make informed decisions about weight loss medication options. Both are prescription-only medicines requiring clinical assessment, and costs vary depending on whether you access treatment privately or through NHS specialist services.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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 vs Wegovy — Clinical Differences and Pricing Context
Mounjaro (tirzepatide) and Wegovy (semaglutide) are both prescription-only GLP-1 weight loss injections licensed in the UK, but they work differently and have distinct cost implications. Mounjaro uses a dual GIP and GLP-1 mechanism—activating two hormone pathways—while Wegovy is a GLP-1-only agonist. Clinical trials show different weight loss outcomes: SURMOUNT data showed Mounjaro participants lost approximately 15–21% body weight at maximum dose, while STEP trial data showed Wegovy participants achieved around 15% average weight loss. Pricing differences reflect manufacturing complexity, patent status, and supply availability. Mounjaro dose titration requires a slower escalation (starting 2.5 mg, reaching maximum 15 mg), while Wegovy escalates faster (0.25 mg to 2.4 mg). Both require a UK prescription following clinical assessment by a licensed prescriber, either through NHS tier 3 weight management services or private online prescribing.
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.
Factors Behind Rising Mounjaro Costs and Your Options
Mounjaro price increases reflect global supply chain pressures, manufacturing capacity constraints, and exceptionally high demand for tirzepatide since its approval. Eli Lilly, the manufacturer, has prioritised UK supply but pricing remains higher than Wegovy at equivalent doses. NHS access through NICE-approved specialist weight management services may avoid private costs entirely, though waiting lists vary significantly by region. Private prescribing costs range broadly depending on dose and provider. Your GP or prescriber can assess whether Mounjaro eligibility aligns with your BMI and health needs using our free BMI calculator above, and discuss whether Wegovy—typically priced lower—might be suitable for your individual circumstances. Individual results vary significantly between both medications.
- 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.
Why has Mounjaro become more expensive than Wegovy in the UK?
Supply constraints and exceptional demand for tirzepatide have driven private sector prices higher. Mounjaro's dual mechanism requires more complex manufacturing than Wegovy's single GLP-1 action. Pricing also reflects patent status and Eli Lilly's capacity to meet global demand. Wegovy (semaglutide) has been available longer and benefits from established supply chains through Novo Nordisk.
Is Mounjaro available on the NHS, and does it cost the same?
Yes, NICE has approved tirzepatide (Mounjaro) for NHS specialist weight management services. NHS access is free at point of care, but availability varies by region and waiting times can be lengthy. NHS eligibility requires referral to tier 3 specialist services and assessment of your BMI and weight-related health conditions.
How do SURMOUNT and STEP trial results compare between these medications?
SURMOUNT-1 (Mounjaro) showed average weight loss of 15–21% body weight at maximum 15 mg dose over 72 weeks. STEP-1 (Wegovy) showed approximately 15% average weight loss at maximum 2.4 mg dose over 68 weeks. Both results were alongside reduced-calorie diet and increased physical activity. Individual outcomes vary significantly.
Which medication is more suitable—Mounjaro or Wegovy?
Suitability depends on your individual health profile, BMI, and prescriber assessment. Both require a prescription following clinical evaluation. Use our GLP-1 weight loss calculator to explore potential outcomes at different doses, then discuss with your prescriber which mechanism and dosing schedule suits you best.
Will Mounjaro prices fall in the UK, or is this the new standard?
Pricing depends on future supply improvements and competition. If tirzepatide supply increases and demand stabilises, private sector prices may moderate. However, any price changes take months to reflect in the market. NHS pricing remains stable regardless of private sector fluctuations.
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.