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 To Apply For Mounjaro In The UK
If you're looking to apply for Mounjaro (tirzepatide) in the UK, you have two main routes: the NHS specialist services or private prescribing through a licensed online provider. Both require a clinical assessment to confirm you're eligible based on your weight, BMI, and health profile. This guide explains the application process for both, and how it compares to applying for Wegovy (semaglutide). The choice between them depends on your circumstances, timeline, and individual health factors — a prescriber will assess which is suitable for you.
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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 Routes To Get Mounjaro
NHS Route: You'll need a referral from your GP to a tier 3 specialist weight management service. Your GP will assess your weight, BMI, and any weight-related health conditions (such as type 2 diabetes, high blood pressure, or sleep apnoea) against NHS eligibility criteria. If you meet the threshold — typically BMI 30 or above, or BMI 27–29.9 with comorbidities — you'll be referred to your local weight management service. However, NHS availability varies significantly by region, and waiting lists can be lengthy. Once assessed by the specialist team, they'll decide whether Mounjaro, Wegovy, or another treatment is appropriate and manage your dose titration over several months.
Private Route: You can apply directly through a GPhC-registered online pharmacy or prescribing service without an NHS referral. You'll complete an online health questionnaire and have a consultation with a UK-licensed prescriber. If approved, you receive a prescription and the medication is dispensed by a registered pharmacy. This route is faster (often within days) but involves payment, typically £129–£320 per month depending on dose.
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 vs Wegovy: Application And Suitability
Both Mounjaro and Wegovy require the same NHS eligibility criteria and both must be prescribed following a clinical assessment — neither is available over-the-counter. The key differences relate to mechanism and trial data: Mounjaro is a dual GIP + GLP-1 receptor agonist, while Wegovy is a GLP-1 agonist only. In clinical trials (SURMOUNT vs STEP), Mounjaro showed slightly higher average weight loss (~15–21% body weight vs ~15% for Wegovy), though individual results vary significantly. Your prescriber will assess which suits you based on your health profile, other medications, and personal circumstances. Use our GLP-1 weight loss calculator to estimate potential outcomes at different doses with either medication, and our BMI calculator to confirm your current BMI and eligibility threshold.
- 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's the fastest way to apply for Mounjaro in the UK?
The private route is fastest — typically 3–7 days from consultation to prescription. NHS specialist services vary by region but often involve waiting lists of weeks to months. The private route requires payment, while NHS is free but may involve a longer wait.
Do I need to be referred by my GP to get Mounjaro privately?
No. For private prescribing, you can apply directly through an online provider without a GP referral. You'll complete a health questionnaire and have an online consultation with a licensed UK prescriber, who will assess your suitability.
What BMI do I need to apply for Mounjaro on the NHS?
Generally BMI 30 or above, or BMI 27–29.9 if you have weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds apply.
Can I switch from Wegovy to Mounjaro after applying?
Yes, but only following a prescriber's assessment. Both medications require separate applications and clinical evaluations. Your prescriber will advise whether switching is appropriate and manage any transition safely.
How long does Mounjaro take to show results?
Most people notice reduced appetite within the first 1–2 weeks. Noticeable weight loss typically occurs over 8–12 weeks. Track your progress using our free progress tracker alongside dose titration over several months.
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.