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 Free on NHS in the UK?
Mounjaro (tirzepatide) is available on the NHS in England, Scotland, Wales, and Northern Ireland, but access is not automatic or free for everyone. NICE has approved tirzepatide for use within NHS specialist weight management services, meaning the medication itself is free if prescribed through the NHS. However, NHS availability is limited — you must be referred to a tier 3 or tier 4 specialist weight management service, waiting lists can be lengthy, and regional availability varies significantly. Many people opt for private prescriptions instead to avoid delays.
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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 vs Private Access to Mounjaro in the UK
NHS route: If approved through an NHS specialist weight management service, Mounjaro is provided free — you pay only your standard prescription charge (£9.90 per item in England, or free if exempt). However, access is restricted. You must be referred by your GP to a tier 3 specialist service, which assesses your eligibility based on BMI and comorbidities. Waiting times for NHS specialist services range from several months to over a year in many regions. NICE guidance approves tirzepatide (Mounjaro's active ingredient) for adults with BMI ≥30, or BMI 27–29.9 with weight-related health conditions including type 2 diabetes, hypertension, or cardiovascular disease.
Private route: Private prescriptions are available without NHS referral through GPhC-registered online prescribing services. Following an online clinical assessment with a UK-licensed prescriber, you receive a private prescription. Private Mounjaro costs typically range from £150–£300+ per month depending on your dose (higher doses cost more). The 2.5 mg starter dose is usually cheaper; the maximum 15 mg dose is most expensive. Costs vary between providers, so it's worth comparing.
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.
How to Get Mounjaro on the NHS or Private Prescription
NHS route: Speak to your GP about weight management support. If your BMI and health profile meet criteria, request referral to your local tier 3 weight management service. This is not automatic — your GP must refer you. Once referred, you'll be assessed by the specialist team, who will discuss whether Mounjaro is suitable and manage your dose titration. Waiting times are variable and can be substantial.
Private route: Access an online consultation with a GPhC-registered prescriber through a private service. You'll answer health questions, provide your weight and height (use our free weight converter if needed), and be assessed for suitability. If approved, a UK-licensed prescriber issues your prescription. You collect it from a UK pharmacy. The whole process typically takes 24–48 hours. Try our GLP-1 weight loss calculator to explore potential results at different Mounjaro doses before deciding.
- 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 completely free on the NHS?
If prescribed through an NHS specialist weight management service, Mounjaro is free except for your standard prescription charge (£9.90 in England, or free if you're exempt). However, NHS access is limited by availability and referral pathways, with long waiting lists in many regions.
How much does Mounjaro cost on private prescription in the UK?
Private Mounjaro typically costs £150–£300+ per month depending on your dose. Starting doses (2.5 mg) are cheaper; maximum doses (15 mg) are more expensive. Costs vary between providers, so compare options.
Do I need a GP referral to get Mounjaro privately?
No. Private prescriptions are available without NHS referral. You can access an online consultation directly with a UK-licensed prescriber through a private service, bypassing GP referral entirely.
How long is the NHS waiting list for Mounjaro?
Waiting times vary significantly by region and NHS trust. Some specialist services have waiting lists of 6–12 months or longer. Private routes avoid NHS waiting times entirely, typically delivering a prescription within 24–48 hours.
Is tirzepatide the same as Mounjaro, and does the cost differ?
Tirzepatide is the active ingredient in Mounjaro — they're the same medication. "Mounjaro" is the brand name. Costs are identical whether you refer to it as Mounjaro or tirzepatide; price depends on dose and provider, not the name used.
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.