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
What Is The Mounjaro Diet And How Do You Access It In The UK?
The "Mounjaro diet" isn't a specific meal plan — it's the lifestyle and eating approach you follow while taking Mounjaro (tirzepatide), a prescription weight management injection. Mounjaro works by reducing appetite and helping you feel fuller, but it's designed to work alongside reduced-calorie eating and increased physical activity, not replace them. Access in the UK is available through NHS specialist weight management services or private online prescribing following a clinical assessment. Understanding both routes, costs, and what to expect can help you make an informed decision about whether Mounjaro is right for you.
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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.
Private Prescription Costs And Access Routes In The UK
In the UK, accessing Mounjaro privately through a GPhC-registered online pharmacy typically costs between £129 and £320 per month, depending on your dose and provider. The variation reflects different starting doses and escalation schedules. At 5 mg per week (common maintenance dose), expect to pay around £150–£200 monthly. At 15 mg per week (maximum dose), costs reach £280–£320 per month. These prices include the clinical assessment and prescription — you don't need an NHS referral. The process is straightforward: complete an online health questionnaire, a UK-licensed prescriber reviews your details and medical history, and if approved, your prescription is sent to a pharmacy for dispensing. Most people receive their first pen within 3–5 working days. Use our free GLP-1 weight loss calculator to explore potential outcomes across different doses, then discuss cost options with a prescriber during your online consultation.
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 Vs Private: Access Routes And What To Expect
NHS Route: Mounjaro is available through tier 3 specialist weight management services following a GP referral. There is no prescription cost (covered by the NHS), but waiting times vary significantly by region — some areas have waits of 6–18 months. Availability depends on your local Integrated Care Board (ICB) funding and capacity.
Private Route: No waiting list; you can start within days of approval. Requires a private prescription fee and ongoing costs per dose. Ideal if you want faster access and can fund treatment privately. Online consultations are confidential and typically take 10–15 minutes. A prescriber will assess your BMI, medical history, and eligibility — use our free BMI calculator above to check your starting point before your consultation. Both routes require the same clinical criteria: BMI ≥30, or BMI 27–29.9 with weight-related health conditions like high blood pressure or type 2 diabetes.
- 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 available on the NHS in the UK?
Yes, Mounjaro (tirzepatide) is available through NHS tier 3 specialist weight management services. You'll need a GP referral and must meet NICE eligibility criteria (BMI ≥30, or 27–29.9 with comorbidities). However, waiting times vary widely by region — some areas have 12–18 month waits. Private access is faster but requires payment.
How much does Mounjaro cost privately in the UK?
Private Mounjaro costs typically range from £129–£320 per month depending on dose. Starting doses (2.5–5 mg) cost around £150–£180; higher maintenance or maximum doses (10–15 mg) cost £250–£320. Prices include the online clinical assessment and prescription.
What is the "Mounjaro diet" exactly?
The Mounjaro diet isn't a branded meal plan. It's the reduced-calorie, balanced diet you follow while taking Mounjaro. The injection reduces your appetite, making it easier to eat less. You'll need to combine Mounjaro with a healthy diet (typically 500–750 kcal deficit per day) and physical activity for best results. Your prescriber or a dietitian can advise on specific nutrition.
Do I need a GP referral for private Mounjaro in the UK?
No. Private prescription Mounjaro is accessed directly through an online consultation with a UK-licensed prescriber — no GP referral needed. You complete a health questionnaire, the prescriber assesses your eligibility, and if approved, you receive a prescription. The entire process takes 1–2 days.
How does Mounjaro (tirzepatide) compare to Wegovy for cost in the UK?
Both are similar in private cost (£129–£320/month depending on dose). Mounjaro uses a dual GIP+GLP-1 mechanism and may produce slightly higher average weight loss in trials (~20% vs ~15%). Wegovy uses GLP-1 only. Cost is similar; choice depends on prescriber recommendation, individual response, and clinical assessment.
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.