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 Can You Get Mounjaro in the UK?
Getting Mounjaro (tirzepatide) in the UK involves two main routes: through NHS specialist weight management services or via private prescribing. Your eligibility depends on your BMI, health conditions, and the assessment made by a qualified prescriber. This guide explains both pathways, what to expect, and how Mounjaro compares to other weight loss options like Wegovy. Understanding your options helps you make an informed decision about weight management that's right for your situation.
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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.
NHS vs Private Access Routes
NHS Route: Mounjaro is available through NHS tier 3 specialist weight management services following referral from your GP. You'll need to be assessed by a multidisciplinary team, and access varies significantly by region. Some areas have shorter waiting lists than others. Once approved, the NHS covers the full cost of the medication and ongoing support. However, waiting times can be substantial in many regions, sometimes extending several months.
Private Route: Private prescribing allows you to access Mounjaro without NHS referral. You complete an online consultation with a UK-licensed prescriber who assesses your eligibility based on your BMI, health history, and current medications. If approved, your prescription is dispensed by a GPhC-registered pharmacy. Private costs typically range from £129–£320 monthly depending on your dose. This route is faster but not covered by the NHS. Both routes require a clinical assessment—you cannot obtain Mounjaro without a valid prescription from a licensed prescriber.
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.
Mounjaro and Wegovy: How They Compare
Both Mounjaro and Wegovy are prescription-only weight loss injections available in the UK, but they work differently. Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, activating two natural hormone pathways. Wegovy (semaglutide) is a GLP-1 agonist only. In clinical trials, Mounjaro helped participants lose an average of 15–21% of body weight, while Wegovy showed approximately 15% average loss—though individual results vary significantly. Both are once-weekly injections. Your prescriber will assess which medication may be more suitable based on your health profile, dose escalation preferences, and individual circumstances. Neither is assured to work the same way for everyone.
- 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.
What is the BMI requirement to get Mounjaro in the UK?
You generally need a BMI of 30 kg/m² or above, or 27–29.9 with at least one weight-related health condition (like type 2 diabetes, high blood pressure, or sleep apnoea). South Asian, Chinese, Black African, and Black Caribbean adults may qualify at lower BMI thresholds. Your prescriber assesses individual eligibility.
How long is the NHS waiting list for Mounjaro?
NHS waiting times vary by region and ICB. Some areas have waiting lists of several months; others are longer. Demand currently exceeds capacity in many regions. Check with your local NHS weight management service or GP for current waiting times in your area.
Can I get Mounjaro on the NHS even if I've never tried diet and exercise?
Most NHS services require evidence of previous weight loss attempts through lifestyle changes. However, each referral is assessed individually. Your GP can discuss your specific situation and refer you to the appropriate tier of care. Private prescribing doesn't have this requirement—clinical assessment is based on current health.
What happens after I'm prescribed Mounjaro—do I need ongoing appointments?
Yes. Both NHS and private routes require follow-up appointments. You'll need dose reviews (every 4 weeks minimum), monitoring for side effects, and ongoing clinical assessment. NHS provides this through specialist services; private patients arrange follow-ups with their prescriber or supporting clinic.
Is private Mounjaro more expensive than private Wegovy?
Costs are comparable—typically £129–£320 per month depending on dose and provider. Mounjaro's maximum dose (15 mg) may cost slightly more than Wegovy's maximum (2.4 mg), but individual pricing varies. Use our GLP-1 weight loss calculator to explore dose options and discuss costs with your prescriber. ```
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.