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 Switch to Wegovy in the UK
Switching to Wegovy (semaglutide) in the UK involves understanding two main routes: NHS specialist services or private prescription. Wegovy is a once-weekly GLP-1 receptor agonist injection licensed for weight management in UK adults. Eligibility depends on your BMI and health profile, and costs vary significantly between the NHS and private prescribing. This guide explains how to access Wegovy, what to expect, and the financial implications of each route so you can make an informed decision.
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.
Wegovy Cost and Access Routes in the UK
In the UK, Wegovy is available through two distinct pathways, each with different costs and timelines.
Private prescription route: Most commonly accessed through online consultations with UK-licensed prescribers registered with the General Pharmaceutical Council (GPhC). Private costs typically range from £129 to £320 per month depending on your dose, with most patients stabilising on the maintenance dose of 2.4mg weekly. Private prescriptions are dispensed by GPhC-registered pharmacies and can be initiated without NHS referral.
NHS route: Available through specialist tier 3 weight management services following GP referral. NHS provision is free at point of use but involves significant regional variation in availability and waiting times that can extend from several months to over a year in many areas. NICE has approved semaglutide for use within NHS services, but not all ICBs (Integrated Care Boards) currently fund it or have capacity to prescribe.
Your eligibility is assessed based on BMI thresholds: BMI 30 or above, or BMI 27–29.9 with weight-related health conditions such as type 2 diabetes, cardiovascular disease, or obstructive sleep apnoea. For South Asian, Chinese, Black African, or Black Caribbean adults, eligibility may start at BMI 27.5 or above due to higher health risks at lower BMI levels.
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.
Switching Routes: NHS vs Private Prescribing
Choosing between NHS and private Wegovy depends on your priorities: waiting time, cost, and convenience.
NHS advantages: Free treatment, medical oversight within the NHS system, integration with your GP records. NHS disadvantages: Significant waiting lists in many regions, limited availability, less flexibility in dose timing.
Private advantages: Faster access (often within 1–2 weeks), no waiting list, flexible scheduling, choice of provider. Private disadvantages: Ongoing monthly costs, no NHS integration.
If switching from another weight loss medication like Mounjaro, your prescriber will manage the transition based on your individual response. Use our free GLP-1 weight loss calculator to explore potential outcomes with Wegovy at different doses, and our BMI calculator to understand your current health context. An online consultation with a licensed prescriber will assess whether Wegovy is suitable for you and determine the appropriate starting dose.
- 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 Wegovy cost per month in the UK?
Private Wegovy costs typically range from £129 to £320 monthly depending on your dose. Lower doses (0.25–1mg) cost less; the maintenance dose of 2.4mg is usually at the higher end. NHS provision is free, but availability varies by region and involves waiting lists.
Can I get Wegovy on the NHS in the UK?
Yes, Wegovy is NICE-approved for NHS use within specialist tier 3 weight management services. Access requires GP referral and assessment by a specialist team. However, availability varies significantly by region, and waiting times can be lengthy—many areas have multi-month queues.
What's the difference between Wegovy and Mounjaro?
Wegovy (semaglutide) is a single GLP-1 receptor agonist; Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist. Wegovy reaches 2.4mg weekly maximum; Mounjaro reaches 15mg. Clinical trials showed Mounjaro had slightly higher average weight loss (~21% vs ~15%), but individual results vary. Both require prescription and clinical assessment.
How long does it take to get Wegovy on the NHS?
NHS waiting times vary by region and ICB. In many areas, specialist weight management referrals can take 3–12 months or longer. Private online prescriptions are typically faster—often assessed and prescribed within 1–2 weeks if eligible.
Do I need a GP referral to get Wegovy privately?
No. Private Wegovy prescriptions are accessed through online consultations with UK-licensed prescribers without requiring a GP referral. Your prescriber will conduct a clinical assessment to confirm eligibility. However, informing your GP is advisable so they're aware you're using weight loss medication.
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.