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
When Will Mounjaro Be Available On The NHS?
Mounjaro (tirzepatide) has already been approved by NICE for use within NHS specialist weight management services in the UK. However, availability varies significantly by region due to funding and demand. Access is typically through tier 3 or tier 4 specialist services, not standard GP prescription. Unlike Wegovy, which has been available longer, Mounjaro is still rolling out across different NHS trusts. Your local GP can check availability in your area and refer you to the appropriate specialist service if you meet eligibility criteria.
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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.
Mounjaro vs Wegovy — NHS Availability and Trial Data
Mounjaro (tirzepatide) received NICE approval for NHS weight management in 2024, making it available through specialist tier 3 services. It uses a dual GIP and GLP-1 mechanism, which differs from Wegovy's single GLP-1 approach. In the SURMOUNT-1 clinical trial, Mounjaro achieved average weight loss of approximately 15–21% body weight at the maximum 15 mg KwikPen dose, depending on the cohort studied. Wegovy (semaglutide) has been available on the NHS for longer and is more widely distributed across regions. STEP trial data showed average weight loss of around 15% body weight on the maximum 2.4 mg dose. Both medications require prescription and clinical assessment. Availability remains limited by NHS capacity, with waiting lists varying from weeks to many months depending on your local NHS trust and integrated care board (ICB).
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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.
How To Access Mounjaro On The NHS — Eligibility and Next Steps
To access Mounjaro through the NHS, you'll typically need a referral from your GP to a specialist tier 3 weight management service in your area. Eligibility criteria include a BMI of 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower BMI thresholds may apply. Your GP will assess whether specialist referral is appropriate and can advise on your local service's current waiting time. Some regions have limited capacity, so you may be offered alternative treatments first. Use our free BMI calculator to check your starting point, then speak with your GP about your options and regional availability.
- 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 definitely available on the NHS now?
Yes, Mounjaro has been approved by NICE for NHS use in weight management services. However, it is not yet available everywhere. Availability depends on your local NHS trust and integrated care board. Some regions have it available now; others are still implementing rollout. Contact your GP or local weight management service to check if it's currently available in your area.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist, while Wegovy (semaglutide) is a GLP-1 agonist only. In trials, Mounjaro showed slightly higher average weight loss (15–21% vs 15%), though individual results vary significantly. Both are once-weekly injections, require prescription, and are available through NHS specialist services, though Wegovy has been available longer.
How long are NHS waiting lists for Mounjaro?
Waiting times vary by region. Some NHS services have waiting lists of several months; others may have shorter waits depending on local demand and funding. Your GP can tell you the current waiting time for your local tier 3 weight management service. Private prescribing options are also available if NHS waiting times are lengthy.
What's the eligibility criteria for Mounjaro on the NHS?
You typically need a BMI of 30 or above, or 25–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. For adults of South Asian, Chinese, Black African, or Black Caribbean backgrounds, lower BMI thresholds apply. Your GP or specialist service will assess your individual eligibility.
Can I get Mounjaro faster if I pay privately?
Yes, private prescribing is available without NHS waiting lists. You'll need an online consultation with a UK-licensed prescriber to assess suitability. Private costs vary by dose and provider, typically ranging from £129–£320 per month. However, NHS prescription is free once prescribed. Your GP can advise on both options.
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.