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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Wegovy Weight Loss Chart: NHS UK Guide
Wegovy (semaglutide) is a prescription-only weekly weight loss injection available in the UK through NHS specialist services and private prescribing. Clinical trials show an average weight loss of around 15% body weight over 68 weeks, though individual results vary significantly. This guide explains realistic weekly weight loss expectations, NHS eligibility criteria, and how Wegovy's dosing schedule affects weight loss progression using UK health data.
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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 Eligibility and Wegovy Weight Loss Expectations
In the UK, Wegovy is prescribed through NHS tier 3 specialist weight management services for adults with a BMI of 30 kg/m² or above, or 27 kg/m² with weight-related health conditions such as type 2 diabetes, high blood pressure, or cardiovascular disease. NICE has approved semaglutide for use within NHS specialist services, though regional availability and waiting times vary significantly across ICBs.
The STEP-1 clinical trial, the primary evidence for Wegovy's weight loss efficacy in the UK, showed participants on the maximum 2.4 mg dose lost an average of 14.9% of their body weight (approximately 15 kg for a 100 kg person) over 68 weeks when combined with a reduced-calorie diet and increased physical activity. Weight loss typically accelerates during dose escalation and continues steadily at maintenance dose. Most weight loss occurs during the first 12–16 weeks as the body adjusts to the medication.
- Starting dose: 0.25 mg weekly — primarily for tolerability, minimal weight loss expected
- Escalation phase (weeks 5–16): doses increase to 0.5 mg, 1 mg, and 1.7 mg — weight loss accelerates
- Maintenance phase (week 17 onwards): 2.4 mg weekly — steady, continued weight loss
- Average weekly weight loss: approximately 0.3–0.5 kg per week at maintenance dose
It is important to understand that weight loss varies considerably between individuals. Some people lose significantly more, others less. Age, starting weight, diet adherence, physical activity level, and individual metabolism all influence outcomes. Use our free GLP-1 weight loss calculator above to estimate potential weight loss at different doses based on your starting weight.
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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 Routes for Wegovy Access in the UK
NHS access: Available through tier 3 specialist weight management services following GP referral. NICE guidance supports NHS prescribing, but availability is inconsistent across regions. Many areas have substantial waiting lists (sometimes 6–24 months), and access depends on commissioning decisions by local Integrated Care Boards. Once prescribed, the NHS covers the cost.
Private access: Available through GPhC-registered online pharmacies following an online clinical assessment with a UK-licensed prescriber. Private Wegovy is accessible without NHS waiting times and does not require GP referral. Costs typically range from £129–£250 per month depending on dose. Both routes are legitimate; private access allows faster initiation alongside a healthcare professional's assessment. Calculate your realistic weight loss using our weight loss calculator above, then discuss your options with your GP or a licensed prescriber to determine the best route for your circumstances.
- 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 weight can I expect to lose with Wegovy in the UK?
Clinical trials showed an average weight loss of around 15% body weight over 68 weeks. For example, someone weighing 100 kg might lose approximately 15 kg. However, individual results vary significantly — some people lose more, others less. Age, diet adherence, activity level, and metabolism all affect outcomes. Always discuss realistic expectations with your prescriber.
Is Wegovy available on the NHS in the UK?
Yes, NICE has approved semaglutide (Wegovy) for NHS specialist weight management services. Access is through tier 3 services following GP referral. Regional availability varies significantly — some areas have long waiting lists. Private prescribing offers faster access if NHS waiting times are lengthy in your area.
What is the Wegovy dosing schedule and how does it affect weight loss?
Wegovy starts at 0.25 mg weekly and escalates every 4 weeks to 0.5 mg, 1 mg, 1.7 mg, and finally 2.4 mg. Weight loss accelerates during escalation (weeks 5–16) as doses increase. The maximum dose of 2.4 mg is maintained long-term. Most weight loss occurs during the first 12–16 weeks. Steady loss continues at maintenance dose.
How does Wegovy compare to Mounjaro for weight loss in UK trials?
Wegovy is a GLP-1 agonist; Mounjaro is a dual GIP/GLP-1 agonist. STEP trial data shows Wegovy averages clinically studied weight loss. SURMOUNT trial data shows Mounjaro averages 15–clinically studied weight loss at higher doses. Both are prescription-only in the UK. Direct comparisons require individual prescriber assessment based on your medical history.
Can I use a weekly weight loss injection if I'm overweight but not obese in the UK?
Yes, if you have a BMI of 27–29.9 kg/m² and at least one weight-related health condition (type 2 diabetes, high blood pressure, cardiovascular disease, sleep apnoea), you may be eligible for a weekly weight loss injection through NHS tier 3 services or private prescribing. Your GP or prescriber will assess your eligibility based on your individual circumstances.
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.