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 — What Clinical Trials Show
Clinical trials show that Wegovy (semaglutide) helps adults lose an average of around 15% of their body weight over 68 weeks. However, individual results vary significantly — some people lose more, some less. This guide explains the clinical data, how it translates to real kilograms and stone, and how Wegovy weight loss compares to NHS healthy weight ranges. Understanding realistic expectations is crucial before starting any weight loss treatment.
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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.
Clinical Trial Data — Average Weight Loss with Wegovy
The STEP-1 clinical trial, which tested Wegovy's effectiveness in adults without type 2 diabetes, found that participants taking the 2.4 mg dose lost an average of 14.9% of their body weight over 68 weeks (approximately 15 months). This translates to roughly 10–15 kg (1st 6lbs to 2st 5lbs) for many UK adults, depending on their starting weight.
In the same trial, participants taking lower doses saw different results:
- 0.5 mg dose: approximately clinically studied weight loss
- 1 mg dose: approximately clinically studied weight loss
- 1.7 mg dose: approximately clinically studied weight loss
- 2.4 mg dose: approximately clinically studied weight loss
Importantly, these results were achieved alongside a reduced-calorie diet and increased physical activity — Wegovy is not a standalone treatment. Weight loss plateaus were common after 6–12 months on the medication.
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.
Factors That Affect Individual Weight Loss Results
Individual results with Wegovy vary widely for several reasons. Starting weight significantly impacts absolute kilograms lost — heavier individuals often lose more weight in raw numbers. Adherence to diet and exercise is critical; Wegovy works best alongside consistent lifestyle changes. Age, metabolism, genetics, and existing health conditions (such as type 2 diabetes or PCOS) all influence how much weight someone loses.
Some people experience rapid initial loss (first 3–4 months) then plateau, whilst others see more gradual but sustained loss. Dose escalation tolerance matters too — if you experience side effects that limit dose increases, you may not reach the 2.4 mg maximum, which could affect total weight loss.
Calculate your healthy weight range using our free BMI calculator above, then track your progress with our progress tracker to monitor realistic, sustainable results over time.
- 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 will I lose on Wegovy?
Clinical trials show an average of clinically studied weight loss on the 2.4 mg dose — roughly 10–15 kg for most UK adults. However, individual results vary significantly based on starting weight, diet adherence, exercise, genetics, and other health factors. Your GP or prescriber can discuss realistic expectations for your personal situation.
Is clinically studied weight loss enough to reach a healthy BMI?
It depends on your starting weight and height. For some people, 15% loss reaches a healthy BMI (under 25); for others, it may reduce BMI but not reach the healthy range. Use our free BMI calculator to check your current BMI and healthy weight range for your height — your GP can discuss whether Wegovy might help you reach it.
How does Wegovy weight loss compare to other methods?
Wegovy's 15% average loss is similar to other GLP-1 medications like semaglutide used off-label for diabetes. Mounjaro (tirzepatide), a dual GIP/GLP-1 medication, shows slightly higher average loss (~20%). Lifestyle changes alone typically achieve 5–10% loss; Wegovy enhances this when combined with diet and exercise.
Why do some people lose more or less weight on Wegovy?
Factors include starting weight, muscle mass, age, metabolism, adherence to calorie deficit, physical activity level, genetics, concurrent medications, and how well you tolerate the medication. Side effects may limit dose escalation, and weight loss often slows after initial months as your body adapts.
When should I expect to see weight loss results?
Most people see noticeable weight loss after 4–8 weeks on Wegovy, with the most significant loss typically in months 3–6. Weight loss tends to plateau after 6–12 months. Our progress tracker helps you log and visualise your journey week by week to stay motivated.
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.