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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Is Mounjaro Available on the NHS?
Yes, Mounjaro (tirzepatide) is available on the NHS in the UK for weight management — but access is limited to specialist weight management services and not available through standard GP prescription. NICE has approved tirzepatide for use within NHS tier 3 and tier 4 specialist services. However, availability varies significantly by region, with considerable waiting lists in many areas. Many people seeking Mounjaro turn to private prescribing as an alternative. This guide explains both routes and what you need to know about NHS eligibility and how to access this dual GIP and GLP-1 receptor agonist treatment.
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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 to Access Mounjaro Through the NHS
NHS access to Mounjaro requires referral to a specialist tier 3 or tier 4 weight management service — you cannot obtain it directly from your GP. You must be referred by your GP to your local Integrated Care Board (ICB) weight management service. Once referred, a specialist multidisciplinary team will assess your eligibility, which includes:
- BMI of 30 kg/m² or above, or BMI of 27–29.9 kg/m² with weight-related health conditions
- Previous engagement with tier 2 services (NHS weight loss programmes)
- Medical assessment and blood tests
- Confirmation that you're suitable for tirzepatide dose titration
If approved, the specialist team will manage your entire treatment pathway, including regular monitoring and dose escalation from the starting 2.5 mg through to the maximum 15 mg weekly injection. However, NHS waiting lists are significant in many regions — some areas report waiting times of 6–18 months or longer. Regional variation in availability is substantial; some ICBs have limited or no Mounjaro provision.
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.
Private Access to Mounjaro in the UK
If you don't want to wait for NHS specialist services, Mounjaro is available privately through GPhC-registered online prescribing services. Private access involves an online consultation with a UK-licensed prescriber who will assess your suitability based on your medical history, current medications, and BMI. If approved, your prescription is dispensed by a registered pharmacy. Private costs typically range from £129–£320 per month depending on your dose (you usually start at 2.5 mg and progress through dose titration as tolerated). Private access is faster than NHS routes — many people receive their first prescription within days. Use our free GLP-1 weight loss calculator to explore potential outcomes at different doses, and our BMI calculator to check your current BMI against NHS eligibility thresholds.
- 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's the difference between NHS and private Mounjaro in the UK?
NHS access is free but requires GP referral to specialist services with significant waiting lists and regional variation. Private access is faster (days vs months) and doesn't require NHS referral, but costs £129–£320/month. Both routes require clinical assessment and prescription — neither is available over-the-counter.
Do I need to try NHS tier 2 weight loss programmes before accessing Mounjaro?
Yes, NHS tirzepatide is typically only prescribed after engagement with tier 2 services (NHS Weight Loss Plan or community programmes). This is part of the staged approach. Private routes may not have this requirement, though clinical assessment still applies.
Is Mounjaro the same as Wegovy or Ozempic?
No. Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist. Wegovy (semaglutide) is a GLP-1 agonist only — both are licensed for weight management in the UK. Ozempic is also semaglutide but is licensed only for type 2 diabetes, not weight loss. All three are prescription-only.
What are the main Mounjaro side effects I should know about?
Common side effects include nausea, diarrhoea, vomiting, and constipation — these often improve as your body adjusts. Serious side effects are rare but can include severe stomach pain (possible pancreatitis) or gallbladder problems. Your prescriber will monitor you for these throughout your treatment.
How does Mounjaro dose titration work?
You start at 2.5 mg once weekly for 4 weeks, then increase to 5 mg for the next 4 weeks. Further increases (7.5 mg, 10 mg, 12.5 mg, 15 mg) happen every 4 weeks as tolerated. Your prescriber may slow titration if side effects are significant. The KwikPen contains 4 doses (4 weeks' supply).
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.