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 Do You Get Mounjaro On The NHS?
Getting Mounjaro on the NHS in the UK is possible but involves navigating specialist weight management services rather than requesting it from your GP. NICE has approved tirzepatide (Mounjaro's active ingredient) for NHS use, but access is limited to tier 3 and tier 4 specialist weight management services. This guide explains the NHS pathway, eligibility criteria, realistic timescales, and what private alternatives look like if NHS waiting lists are too long in your area.
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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 Access Pathway For Mounjaro
Accessing Mounjaro through the NHS involves a structured referral pathway. Your GP cannot simply prescribe Mounjaro — it must be prescribed by a specialist weight management service. Here's how the process works:
- Step 1: Discuss with your GP. Your GP assesses your weight, BMI, and weight-related health conditions (type 2 diabetes, high blood pressure, sleep apnoea, cardiovascular disease). They determine whether you meet NHS tier 3 referral criteria.
- Step 2: Referral to specialist service. If eligible, your GP refers you to your local NHS integrated care board (ICB) weight management service — this is tier 3 (specialist outpatient) or tier 4 (specialist inpatient) depending on your needs and local availability.
- Step 3: Specialist assessment. The weight management team reviews your medical history, lifestyle, previous weight loss attempts, and comorbidities. They may arrange blood tests and other investigations.
- Step 4: Prescription and titration. If approved, you receive a Mounjaro KwikPen prescription and begin dose titration — starting at 2.5 mg weekly and escalating gradually. The service monitors your progress regularly.
This process takes time. Many NHS regions have waiting lists of 6–18 months for specialist weight management services, depending on local capacity and demand.
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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 Eligibility And Private Alternatives
NHS eligibility: You typically qualify for NHS weight management referral if you have a BMI of 30 or above, or BMI of 27–29.9 with a weight-related health condition. South Asian, Chinese, Black African, and Black Caribbean adults may qualify at BMI 27.5 or above due to higher cardiovascular risk at lower weights.
Private route: If NHS waiting lists are unacceptable, Mounjaro is available privately through UK-licensed online prescribers following an online clinical assessment. Costs typically range from £130–£320 per month depending on dose. This route bypasses waiting lists but requires direct payment. Private prescriptions are dispensed by GPhC-registered pharmacies. Both NHS and private routes use the same medication — the difference is access speed and cost responsibility.
Try our free BMI calculator above to check your starting BMI, and our GLP-1 weight loss calculator to estimate potential outcomes at different Mounjaro doses.
- 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 average NHS waiting time for Mounjaro?
Waiting times vary significantly by region (ICB). Some areas have waiting lists of 6–12 months; others may be 18+ months. Many NHS trusts have suspended new referrals due to capacity issues. Contact your local ICB directly for current waiting times in your area.
Can my GP prescribe Mounjaro directly?
No. GPs cannot prescribe Mounjaro for weight management. Only NHS specialist weight management services (tier 3 or tier 4) can prescribe it. Your GP can refer you to the service, but the prescription itself comes from the specialist team.
What's the difference between NHS and private Mounjaro?
The medication is identical — both use the same Mounjaro KwikPen. The difference is access speed (NHS: months-long wait; private: 1–2 weeks) and who pays (NHS: free; private: £130–£320/month). Private prescriptions require clinical assessment through an online consultation with a UK-licensed prescriber.
Do I need to lose weight before NHS Mounjaro referral?
No, there's no weight loss requirement. However, some NHS services may ask about previous weight loss attempts to show you've tried other approaches first. NICE guidance recommends offering Mounjaro as part of a comprehensive weight management programme, not in isolation.
What happens after Mounjaro is prescribed — how often do I see the service?
You'll typically have regular follow-ups — usually every 4 weeks during dose titration (weeks 1–20), then every 8–12 weeks once stable. Appointments monitor weight loss, side effects, adherence, and overall health. Your GP may also be involved in ongoing monitoring once you're established on the medication.
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.