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 Average Weight Loss and Your Healthy Weight Range
Clinical trials show that Wegovy (semaglutide) helped participants lose an average of around 15% of their body weight over 68 weeks — though individual results vary significantly. This page explains what that average weight loss means for your BMI and ideal body weight according to NHS guidelines. Your actual results will depend on your starting weight, dose, diet, and physical activity. Use our free BMI calculator above to understand where you currently sit and what a healthy weight range looks like for your height.
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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.
Understanding Wegovy Weight Loss in BMI Terms
The STEP-1 clinical trial showed that participants on Wegovy 2.4 mg (the maximum dose) lost approximately 14.9% of their body weight over 68 weeks alongside reduced-calorie diet and increased physical activity. To put this in perspective:
- A person weighing 100 kg might lose around 15 kg on average (100 kg − 15% = 85 kg)
- A person weighing 80 kg might lose around 12 kg on average (80 kg − 15% = 68 kg)
- A person weighing 120 kg might lose around 18 kg on average (120 kg − 15% = 102 kg)
However, clinical trial averages mask individual variation — some participants lost 5%, others lost 20% or more. Your prescriber will monitor your progress and adjust your dose or approach based on your individual response. Weight loss with Wegovy typically plateaus after 12–16 weeks on the maintenance dose. Try our GLP-1 weight loss calculator to estimate potential weight loss at different doses based on your starting weight.
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 Wegovy Weight Loss Affects Your BMI and Healthy Weight Range
According to NHS guidelines, a healthy weight range has a BMI between 18.5 and 24.9. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends a lower threshold (18.5–22.9) due to increased health risk at higher BMI levels.
If you lose 15% of your body weight with Wegovy, your BMI will improve proportionally. For example, if your current BMI is 32 (obese range), a clinically studied weight loss could bring you to approximately BMI 27 (overweight range). To calculate your personal ideal body weight and healthy weight range for your height, use the BMI calculator on this page — enter your height and it will show you the weight range that corresponds to a healthy BMI. This gives you a concrete target to work towards alongside Wegovy treatment.
- 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.
What's the average weight loss on Wegovy in the UK?
Clinical trials showed an average loss of around 15% of body weight over 68 weeks on Wegovy 2.4 mg. This means someone weighing 100 kg might lose approximately 15 kg. However, individual results vary significantly — some lose 5%, others lose 20% or more. Always combine Wegovy with a reduced-calorie diet and physical activity.
How does Wegovy weight loss translate to BMI improvement?
BMI improves proportionally with weight loss. If you lose 15% of body weight, your BMI will drop by approximately the same percentage. A person with a starting BMI of 32 losing 15% of weight would fall to around BMI 27. Use the BMI calculator on this page to see your target healthy weight range for your height.
Is Wegovy weight loss permanent after you stop taking it?
Weight loss achieved with Wegovy is not automatically maintained if you stop treatment. Most people regain weight gradually after stopping, particularly if dietary and lifestyle changes aren't sustained long-term. Wegovy is typically used as part of a comprehensive weight management plan, not as a standalone solution.
How quickly does weight loss happen on Wegovy?
Weight loss on Wegovy typically begins within 2–4 weeks and accelerates over the first 12–16 weeks. Participants in trials lost the most weight between weeks 8 and 20. After week 20, weight loss typically plateaus. Your individual timeline depends on your dose, metabolism, diet, and activity level.
What is the average UK healthy weight for my height?
Healthy weight depends on your height and body composition. The NHS defines healthy weight as a BMI between 18.5 and 24.9. For a person 5ft 8in (173 cm) tall, this corresponds to roughly 55–74 kg (8st 9lbs–11st 9lbs). Use the healthy weight calculator above to find the exact range for your height.
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.