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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How Much Does Mounjaro Cost in the UK?
Mounjaro (tirzepatide) and Wegovy (semaglutide) are both prescription-only weight loss injections available in the UK, but costs differ significantly depending on whether you access them through the NHS or privately. Understanding the pricing and what affects cost — including your specific dose — is essential when comparing your options. This guide covers both medications side-by-side so you can make an informed decision alongside your GP or 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 and Wegovy Pricing in the UK
Mounjaro pricing (private): Typically costs between £129 and £320 per month depending on your dose. As a tirzepatide dual GIP and GLP-1 agonist, the KwikPen is delivered for 4 weeks at a time.
Wegovy pricing (private): Usually ranges from £160 to £300 per month depending on dose. Semaglutide's GLP-1 mechanism involves five dose escalations from 0.25 mg to 2.4 mg.
NHS access: Both medications are available through NHS specialist weight management services, but only for eligible adults following clinical assessment. Regional variation exists — some areas have longer waiting lists or stricter criteria. Cost to you on the NHS is zero, but availability depends on your local Integrated Care Board (ICB) and referral pathway.
- Private prescriptions require an online clinical assessment with a UK-licensed prescriber
- Prices vary by provider and dose level
- Monthly subscriptions often include your clinical assessment and prescription
- Stopping treatment usually means costs stop immediately (no long-term contracts)
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 Trials and Individual Suitability
Clinical trial data shows both medications deliver meaningful weight loss. The SURMOUNT-1 trial demonstrated Mounjaro (tirzepatide) delivered average weight loss of 15–21% of body weight at the maximum 15 mg dose. The STEP-1 trial for Wegovy (semaglutide) showed average weight loss of approximately 15% at the maximum 2.4 mg dose. Both results were achieved alongside reduced-calorie diet and increased physical activity.
Which medication is right for you depends on individual factors — not cost alone. Your GP or prescriber will assess your medical history, current medications, and health goals. Some people respond better to one mechanism than the other. Try our free GLP-1 weight loss calculator to understand potential outcomes at different doses, then discuss your options with a licensed prescriber.
Eligibility is the same for both: Adults with a BMI of 30 kg/m² or above, or BMI 27–29.9 with weight-related health conditions (type 2 diabetes, high blood pressure, cardiovascular disease, or sleep apnoea). South Asian, Chinese, Black African, and Black Caribbean adults may be eligible from BMI 27.5 or above due to higher health risks at lower weights.
Both require a clinical assessment before prescription. Neither medication is suitable during pregnancy or whilst breastfeeding. Your prescriber will determine which is appropriate based on your individual circumstances, not cost. Use our free BMI calculator above to check your current BMI and understand where you sit relative to eligibility thresholds.
- 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 cheaper than Wegovy in the UK?
Pricing varies by provider and dose, but generally both fall in similar ranges (£129–£320/month). Mounjaro may be slightly cheaper at lower doses, whilst Wegovy at maximum dose (2.4 mg) can exceed Mounjaro costs. Always compare current prices from accredited providers, as they change regularly.
Can I get Mounjaro or Wegovy free on the NHS?
Yes, both are available through NHS specialist tier 3 weight management services if you meet eligibility criteria and are referred by your GP. Access is free but availability varies by region and waiting lists can be long. Private access bypasses the NHS queue but involves monthly costs.
What's the difference between Mounjaro and Wegovy mechanisms?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist — it activates two natural hormone pathways. Wegovy (semaglutide) is a GLP-1 agonist only — single mechanism. Both reduce appetite and support feeling fuller, but tirzepatide's dual action may offer slightly different effects for some people.
Does dose affect Mounjaro cost?
Yes, Mounjaro costs typically increase with dose. Starting doses (2.5–5 mg) are usually cheapest; mid-range doses (7.5–10 mg) moderate; and maximum dose (15 mg) most expensive. Titration (gradually increasing dose) means initial costs are lower.
What if Mounjaro doesn't work for me — can I switch to Wegovy?
Yes, you can switch between medications with prescriber guidance. There's no official conversion chart, but approximate equivalences exist (Mounjaro 10 mg ≈ Wegovy 1.7 mg; Mounjaro 15 mg ≈ Wegovy 2.4 mg). Any switch should be managed by your prescriber, not self-initiated.
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.