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
How Do I Get Mounjaro On The NHS?
Getting Mounjaro (tirzepatide) on the NHS involves a referral to specialist weight management services in your area, though access varies significantly by region. The NHS has approved tirzepatide through NICE, but it's not routinely prescribed in general practice — you'll need to be referred to a tier 3 or tier 4 weight management service by your GP. Waiting times can be substantial in many areas. Alternatively, Mounjaro is available privately through UK-registered online prescribers following a clinical assessment. Understanding both pathways can help you decide which route suits your circumstances best.
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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 vs Private Access — Key Differences
NHS pathway: Your GP must refer you to a specialist tier 3 or tier 4 weight management service. These are multidisciplinary teams offering dietary support, behaviour change coaching, and prescription medications including tirzepatide. However, availability is heavily dependent on your local integrated care board (ICB). Some regions have comprehensive services with shorter waiting lists; others have significant delays of 6–18 months or longer. Once referred, a specialist clinician will assess your eligibility based on BMI (≥30 kg/m², or ≥27 with weight-related health conditions), medical history, and previous weight loss attempts.
Private pathway: You can access Mounjaro through a GPhC-registered online pharmacy following an online consultation with a UK-licensed prescriber. This typically takes 24–48 hours from assessment to prescription. Private costs range from approximately £130–£300 per month depending on your dose. You bypass NHS waiting lists but pay out of pocket. Both pathways require a prescription and clinical assessment — neither is available without prescriber evaluation.
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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.
Mounjaro vs Wegovy — Which Medication & How They're Accessed
Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are licensed for weight management in the UK and available through NHS specialist services or private prescribing. The key difference: Mounjaro is a dual GIP and GLP-1 receptor agonist, while Wegovy is a GLP-1 agonist only. In clinical trials, Mounjaro showed average weight loss of approximately 15–21% of body weight, whereas Wegovy showed around 15%. However, individual results vary significantly — suitability depends on your health profile, other medications, and how you respond. Your prescriber (whether NHS or private) will assess which is appropriate for you. Both require dose titration over 16–20 weeks, starting at lower doses and increasing gradually. Neither is suitable if you're pregnant, breastfeeding, or under 18.
- 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.
How long is the NHS waiting list for Mounjaro?
Waiting times vary by region. Some areas have tier 3 weight management services with waiting lists of 3–6 months; others have waits of 12–18 months or longer. Contact your local integrated care board or ask your GP about typical waiting times in your area. Private access is available within 1–2 days if you prefer not to wait.
Do I need a GP referral to get Mounjaro privately?
No. Private online prescribers do not require a GP referral. You can access Mounjaro through a private online consultation directly. However, it's good practice to inform your GP you're starting weight management treatment, especially if you take other medications. Your GP should monitor your progress.
What's the difference between GIP and GLP-1, and why does it matter?
GLP-1 is a natural hormone that reduces appetite and helps you feel fuller. GIP is another hormone that also affects appetite and metabolism. Mounjaro activates both (dual action), which is why it showed slightly higher average weight loss in clinical trials than single GLP-1 medications like Wegovy. However, both are effective, and individual response varies.
Can I switch from Wegovy to Mounjaro on the NHS?
Possibly, but it depends on your NHS weight management service and clinical circumstances. If Wegovy isn't working well or you experience side effects, your specialist may recommend switching. There's no official NHS conversion chart between the two — any switch must be managed by your prescriber with appropriate washout periods.
What happens if I don't meet NHS BMI thresholds?
If your BMI is below the NHS eligibility threshold (usually 30, or 27 with health conditions), you won't qualify for NHS-funded medication. However, you may still be eligible for private prescribing if a UK-licensed prescriber deems it appropriate following clinical assessment. Eligibility criteria differ between NHS and private services.
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.