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
What Is Mounjaro Used For in the UK?
Mounjaro (tirzepatide) is a prescription-only weight management injection licensed in the UK for adults living with excess weight. It's a once-weekly injectable medicine that may help reduce appetite and support sustainable weight loss when used alongside a reduced-calorie diet and increased physical activity. Access to Mounjaro varies depending on whether you pursue NHS or private prescription routes, and costs differ significantly between the two pathways. Understanding your options, eligibility, and what to expect can help you make an informed decision about whether this medication is right for you.
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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.
How Much Does Mounjaro Cost in the UK?
Private prescription costs for Mounjaro in the UK typically range from £130–£280 per month, depending on the dose prescribed and the provider. Starting doses (2.5 mg) are usually at the lower end of this range, while higher maintenance doses (10–15 mg) cost more. Costs may also vary if you're prescribed multiple pens per month or if additional services (such as repeat consultations or lifestyle support) are included.
NHS access is available but significantly limited. Mounjaro is approved for use within NHS specialist weight management services (tier 3), meaning you cannot simply request it from your GP. You must be referred to a specialist service, assessed for eligibility, and have capacity availability — many areas have waiting lists of several months or longer. If prescribed through the NHS, there is no prescription charge beyond the standard £9.90 (or free if eligible).
- Private costs reflect the medication price, consultation fees, and pharmacy dispensing margins
- NHS prescriptions are heavily subsidised but access is restricted to specialist services with limited capacity
- Private online consultations typically cost £20–£50 and are required before prescription
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.
NHS vs Private: Which Route Is Right for You?
NHS route: Requires referral from your GP to a tier 3 specialist weight management service. Eligibility is assessed based on BMI, health conditions, and readiness for treatment. The advantage is lower cost, but waiting times can be substantial and availability varies dramatically by region (ICB area). You'll typically receive support including dietitian consultations and lifestyle advice.
Private route: No waiting lists. You complete an online consultation with a UK-licensed prescriber, and if approved, your prescription is dispensed by a GPhC-registered pharmacy. Faster access but higher personal cost. The process typically takes 2–5 days from consultation to first delivery. Use our GLP-1 weight loss calculator to explore potential outcomes at different doses, and our BMI calculator to confirm your starting point before consultation.
- 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 available on the NHS in my area?
NHS availability varies significantly by region. Some ICBs (Integrated Care Boards) have established tiered services and prescribe Mounjaro; others have restricted access or waiting lists of 6–12+ months. Contact your GP to ask whether your local NHS weight management service offers Mounjaro. They can check your area's current capacity and eligibility criteria.
What happens during a private online consultation for Mounjaro?
A UK-licensed prescriber will review a health questionnaire, ask about your medical history, weight loss goals, and previous attempts. They'll check your BMI, any weight-related health conditions, and contraindications. If approved, they'll issue a prescription and explain storage, injection technique, and what to expect. The entire consultation takes 15–30 minutes and costs between £20–£50.
Can I get Mounjaro on private prescription without seeing my GP first?
Yes. Private online prescribers can issue Mounjaro prescriptions independently of your GP. However, it's always sensible to inform your GP that you're starting the medication, especially if you take other medications or have underlying health conditions. Your GP should be aware of all treatments you're using.
How quickly can I start Mounjaro on a private prescription?
Once your online consultation is approved, your prescription is typically dispensed within 1–3 business days. Delivery to your home usually takes 2–5 working days depending on location and courier. Most people receive their first Mounjaro KwikPen within 5–10 days of their consultation date.
What's the difference between private Mounjaro costs and Wegovy costs?
Costs are broadly similar across UK private providers, typically £130–£280/month. Mounjaro and Wegovy pricing depends on dose and provider rather than the medication itself. Compare providers for your specific dose. Tirzepatide (Mounjaro) is a dual GIP/GLP-1 agonist, whilst semaglutide (Wegovy) is a GLP-1 agonist only — clinical outcomes differ individually, and prescribers choose based on your health profile.
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.