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
Is Mounjaro Available On The NHS In The UK?
Yes, Mounjaro (tirzepatide) is available on the NHS for weight management in the UK, but access is more complex than asking your GP for a prescription. NICE has approved tirzepatide for use within specialist NHS weight management services — meaning you'll need a referral to tier 3 or tier 4 services rather than standard GP prescription. Availability and waiting times vary significantly by region. Many NHS areas have substantial waiting lists, while others have limited capacity. This is why many people in the UK are also exploring private prescription routes to access Mounjaro more quickly, often comparing it with Wegovy, the other main weight loss injection option available.
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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.
How Do Mounjaro And Wegovy Differ On The NHS?
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are licensed for weight management in the UK, but they work differently and have different approval status on the NHS. Mounjaro is a dual GIP and GLP-1 receptor agonist — meaning it works through two separate hormone pathways — while Wegovy is a GLP-1 receptor agonist only. In clinical trials, the mechanisms showed different results: SURMOUNT trial data showed Mounjaro helped participants lose an average of 15–21% of body weight at maximum dose, whilst STEP trial data showed Wegovy achieved approximately 15% average weight loss. Both are prescription-only and require a clinical assessment. The choice between them — when both are available through NHS specialist services — is made by your prescriber based on individual health factors, medical history, and what they believe is most suitable for you.
- Mounjaro (tirzepatide): Once-weekly injection, dual GIP+GLP-1 mechanism, doses 2.5–15 mg
- Wegovy (semaglutide): Once-weekly injection, GLP-1 mechanism only, doses 0.25–2.4 mg
- Both: Require NHS specialist referral, varying regional availability, prescription-only
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 Access Routes And Private Options
To access Mounjaro or Wegovy through the NHS, you'll need to be referred by your GP to a tier 3 specialist weight management service — not a standard GP prescription. Eligibility depends on BMI and weight-related health conditions (type 2 diabetes, hypertension, cardiovascular disease, or sleep apnoea). However, NHS waiting lists can be lengthy in many areas, sometimes taking months or years. Many UK adults seeking faster access turn to private prescription routes through GPhC-registered online pharmacies, which offer both Mounjaro and Wegovy following an online clinical assessment with a UK-licensed prescriber. Use our free BMI calculator and GLP-1 weight loss calculator to understand your current position and explore potential options with a prescriber — whether NHS or private.
- 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.
Can I get Mounjaro free on the NHS?
Mounjaro is approved for NHS use through specialist tier 3 weight management services, but availability varies by region and waiting lists can be very long. Your GP can refer you to your local specialist service if you meet eligibility criteria (BMI 30+ or 27+ with weight-related conditions). Access is not assured and depends on your local NHS area's capacity.
What's the difference between Mounjaro and Wegovy?
Mounjaro (tirzepatide) is a dual GIP+GLP-1 receptor agonist, whilst Wegovy (semaglutide) is a GLP-1 agonist only. SURMOUNT trials showed Mounjaro achieved 15–21% average weight loss, whilst STEP trials showed Wegovy achieved approximately 15%. Both are once-weekly injections. The choice between them is made by your prescriber based on your individual circumstances.
How long is the NHS waiting list for Mounjaro?
Waiting times vary significantly by NHS region and local specialist service capacity. Some areas have waiting lists of several months to over a year, whilst others have more immediate access. Ask your GP about waiting times in your local NHS area when requesting a referral to tier 3 weight management services.
Can I buy Mounjaro privately in the UK?
Yes, Mounjaro is available through private prescription from UK-licensed prescribers via GPhC-registered online pharmacies. You'll need to complete an online clinical assessment, and costs typically range from £129–£320 per month depending on dose. Private access does not require NHS referral or waiting lists.
Is Mounjaro or Wegovy better for weight loss?
Both are effective for weight management, but individual results vary. Clinical trial data shows Mounjaro achieved slightly higher average weight loss than Wegovy, but suitability depends on your personal health factors, medical history, and how you respond. Your prescriber will assess which is most appropriate for you.
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.