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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Mounjaro and NICE Guidelines for Weight Loss in the UK
Mounjaro (tirzepatide) has been approved by NICE for use within NHS weight management services in the UK. This means eligible adults can potentially access this weekly weight loss injection through specialist NHS tier 3 weight management services, alongside a reduced-calorie diet and increased physical activity. However, NHS access varies significantly by region, and waiting times can be substantial. Understanding the NICE guidance, eligibility criteria, and how the NHS pathway works is essential for anyone considering this treatment option.
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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 Eligibility and NICE Approval for Mounjaro
NICE approved Mounjaro for NHS use in 2024 as part of the tirzepatide technology appraisal. The approval means tirzepatide is recommended for adults with obesity (BMI ≥30) or overweight (BMI 27–29.9) with weight-related health conditions, when used alongside a reduced-calorie diet and increased physical activity.
Eligibility for NHS Mounjaro includes:
- BMI of 30 kg/m² or above, or BMI of 27–29.9 with conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease
- Lower thresholds for South Asian, Chinese, Black African, or Black Caribbean adults (BMI 27.5 or above)
- Age 18 or over
- Not pregnant, planning pregnancy, or breastfeeding
- No contraindications (e.g. history of medullary thyroid cancer)
Access is through NHS tier 3 specialist weight management services, typically following a GP referral. Regional availability varies significantly — some areas have lengthy waiting lists, whilst others may have more limited access. Your GP can advise whether your local ICB (Integrated Care Board) funds Mounjaro through tier 3 services.
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 Access to Mounjaro in the UK
There are two main routes to access Mounjaro in the UK. NHS access is provided through tier 3 specialist weight management services following a GP referral and assessment. This is typically free at the point of use but involves waiting times and regional variation. Private access is available through GPhC-registered online prescribing services, which offer faster access without NHS referral but require payment (typically £150–£350 per month depending on dose).
Both routes require a clinical assessment from a UK-licensed prescriber to ensure Mounjaro is appropriate. You can use our free BMI calculator to check your starting point, and our GLP-1 weight loss calculator to see projected results at different Mounjaro doses. If you decide to pursue NHS access, speak with your GP about referral to your local tier 3 service.
- 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 does NICE approval mean for Mounjaro on the NHS?
NICE approval means Mounjaro is recommended as an effective treatment for weight management within NHS specialist services. It's based on clinical evidence that Mounjaro can help eligible adults lose weight alongside lifestyle changes. However, NICE approval doesn't assures automatic access — funding and availability depend on your local NHS region.
How long are NHS waiting times for Mounjaro?
Waiting times vary significantly by region. Some tier 3 services have waiting lists of several months to over a year. You can contact your local weight management service through your GP for current waiting times. Some people choose private access to avoid waiting lists, though this involves a cost.
Can I get Mounjaro on the NHS if my BMI is between 27 and 29.9?
Yes, you may be eligible if your BMI is 27–29.9 and you have a weight-related health condition such as type 2 diabetes, high blood pressure, or cardiovascular disease. Lower thresholds apply for people of South Asian, Chinese, Black African, or Black Caribbean heritage. Your GP or specialist will assess your individual eligibility.
What's the difference between NHS and private Mounjaro access?
NHS access is free at point of use but involves referral, assessment, and potential waiting times. Private access is faster and doesn't require NHS referral, but you pay per injection (typically £150–£350 monthly). Both require a clinical assessment and prescription from a licensed prescriber.
Can I switch from private Mounjaro to NHS Mounjaro?
Yes, you can request a referral to your GP for NHS specialist services at any time. Your GP can refer you to your local tier 3 weight management service. However, you may need to re-enter the referral process, and you may not be able to continue your current private prescription whilst waiting for NHS assessment.
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.