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 to Access Mounjaro: NHS vs Private Prescription in the UK
Getting Mounjaro in the UK depends on whether you access it through the NHS or via a private prescription. Your GP can refer you to specialist weight management services for NHS access, but availability varies significantly by region and waiting times can be lengthy. Alternatively, private prescription routes offer faster access through online clinical assessments. Understanding both pathways, their costs, eligibility requirements, and what to expect helps you make an informed decision about weight management options available to you. MyWeightCheck's free GLP-1 weight loss calculator can help you explore potential outcomes at different doses.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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 in the UK
Private Mounjaro prescriptions are typically the faster route, with costs ranging from approximately £129 to £320 per month depending on dose and provider. A private clinical assessment through a GPhC-registered online pharmacy involves completing a medical questionnaire reviewed by a UK-licensed prescriber. If approved, your prescription is dispensed directly to you—no NHS referral needed. The Mounjaro KwikPen contains four weekly doses, so each pen typically covers one month of treatment. Costs vary between providers, so comparing options is worthwhile. Private access means you can start treatment within days rather than months, though you bear the full cost yourself. Many people choose private access when NHS waiting lists are long or unavailable in their area.
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: Referral, Eligibility, and Waiting Times
NHS access to Mounjaro is through specialist tier 3 weight management services, typically following a referral from your GP. NICE has approved tirzepatide for use within these specialist services, but availability depends on your region's integrated care board (ICB) funding and capacity. Eligibility criteria include a BMI of 30 kg/m² or above, or BMI of 27–29.9 with weight-related health conditions such as type 2 diabetes, hypertension, or cardiovascular disease. South Asian, Chinese, Black African, and Black Caribbean adults may have lower BMI thresholds. NHS treatment is free once prescribed, but waiting times can range from several months to over a year in some areas. Your GP can advise on local availability and the referral process.
- 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 much does Mounjaro cost on private prescription in the UK?
Private Mounjaro prescriptions typically cost £129–£320 per month depending on your dose and the provider. Each KwikPen contains four weekly doses, so costs cover approximately one month. Compare providers before starting, as prices vary. This is the full cost you pay yourself—private insurance rarely covers weight management medication.
Can I get Mounjaro free through my NHS GP?
Your GP can refer you to specialist NHS weight management services where Mounjaro may be prescribed free. However, NHS access depends on your region's funding and availability. Many areas have long waiting lists. Your GP will assess your eligibility (BMI ≥30, or ≥27 with health conditions) and explain your local options.
How long does a private prescription assessment take?
Private clinical assessments typically take 24–48 hours. You complete a medical questionnaire online, a UK-licensed prescriber reviews it, and if approved, your prescription is sent to a GPhC-registered pharmacy for dispensing. Most people receive their first KwikPen within 3–7 days.
Is Mounjaro cheaper than Wegovy in the UK?
Pricing varies between providers and doses. Both Mounjaro (tirzepatide) and Wegovy (semaglutide) typically cost in similar ranges on private prescription—roughly £129–£320 per month. Exact costs depend on your dose, the provider, and any package deals. Compare specific providers for accurate pricing.
What eligibility criteria does my GP use for NHS Mounjaro?
NHS eligibility typically requires a BMI of 30 kg/m² or above, or BMI of 27–29.9 with weight-related health conditions like type 2 diabetes, hypertension, or cardiovascular disease. Lower thresholds apply to South Asian, Chinese, Black African, and Black Caribbean adults. Use our free BMI calculator to check your BMI and discuss eligibility with your GP.
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.